In vitro antiprotozoal and cytotoxic activity of 33 ethonopharmacologically selected medicinal plants from Democratic Republic of Congo

Self-Medication in Humans (Homo sapiens) and Bonobos (Pan paniscus) in the Democratic Republic of the Congo

In this article I engage with the complex interplay of primates, plants and parasites. We learn about the ethnobotanical records of an indigenous population and their medicinal plants, and get a glimpse into the interplay of man and ape in a jointly used ecosystem. I combine my long-term research on free-living bonobos, a species endemic to the Democratic Republic of the Congo, with historical work. I show the surprising and extraordinary ingestion of Manniophyton fulvum, a wild Euphorbiaceae plant widely used across Africa, bearing specific chemical and mechanical properties that make it suitable for gastro-intestinal self-care.

Ethnobotany, phytochemistry, and biological activities of Psidium guajava in the treatment of diarrhea: a review

Psidium guajava: is a tropical tree that is widely used in traditional medicine, especially for treating diarrhea. While P. guajava has been the subject of numerous reviews, none have specifically examined its ethnobotany, pharmacology, and phytochemistry in relation to its antidiarrheal activity. This review aims to summarize the evidence of effectiveness and safety of P. guajava in the treatment of diarrhea. Literature searches were conducted through Web of Science, PubMed, and ScienceDirect by using keywords "Psidium guajava" and "diarrhea" in October 2022. A total of 189 studies were included in this review. P. guajava is widely used in traditional medicine in 44 countries. Decoction and oral were the most represented method of preparation and administration, respectively, while leaves represented the most frequently cited part of the plant. Around 27 antidiarrheal or antibacterial compounds have been isolated and identified, including benzophenone glycosides, terpenes, polysaccharides, phenols, and flavonoids. This article presents ethnobotanical and pharmacological evidence for the efficacy of P. guajava leaves in the treatment of diarrhea and provides reference information for further investigation of this plant. However, despite the large number of publications on the topic, there are still some questions to answer: are quercetin and its glycosides the only ones to act as antidiarrheal agents? What is the mechanism of action of P. guajava antidiarrheal compounds? are the use of guava leaves safe in all types of populations including children, and at what dosage? To answer these questions, more complete phytochemical studies and systematic clinical trials are needed.

Phytochemical screening, antioxidant analyses, and in vitro and in vivo antimalarial activities of herbal medicinal plant - Rotheca serrata (L.) Steane & Mabb

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria is a major global health concern that is presently challenged by the emergence of Plasmodium falciparum (Pf) resistance to mainstay artemisinin-based combination therapies (ACTs). Hence, the discovery of novel and effective antimalarial drugs is pivotal to treating and controlling malaria. For many years, traditional plant-based herbal medicines have been employed in the treatment of various illnesses. Rotheca serrata (L.) Steane & Mabb. belongs to the Lamiaceae family that has been traditionally used to treat, cure, and prevent numerous diseases including malaria.

AIM

The present investigation sought to assess the phytoconstituents, antioxidant, cytotoxicity, antimalarial activities of Rotheca serrata extract and its fractions. The in vitro antiplasmodial activity was assessed in chloroquine-sensitive Pf3D7 and artemisinin-resistant PfCam3.IR539T cultures, and the in vivo antimalarial activity was analyzed in Plasmodium berghei (Pb) ANKA strain-infected BALB/c mouse model.

MATERIALS AND METHODS

The fresh leaves of Rotheca serrata were extracted in methanol (RsMeOH crude leaf extract). A portion of the extract was used to prepare successive solvent fractions using ethyl acetate (RsEA) and hexane (RsHex). The in vitro antiplasmodial activity was evaluated using [3H]-hypoxanthine incorporation assays against Pf3D7 and PfCam3.IR539T cultures. In vitro cytotoxicity study on HeLa, HEK-293T, and MCF-7 cell lines was carried out using MTT assay. The human red blood cells (RBCs) were used to perform the hemolysis assays. In vitro antioxidant studies and detailed phytochemical analysis were performed using GC-MS and FTIR. The four-day Rane's test was performed to evaluate the in vivo antimalarial activity against Pb ANKA strain-infected mice.

RESULTS

Phytochemical quantification of Rotheca serrata extract (RsMeOH) and its fractions (RsEA and RsHex) revealed that RsMeOH crude extract and RsEA fraction had higher contents of total phenol and flavonoid than RsHex fraction. The RsEA fraction showed potent in vitro antiplasmodial activity against Pf3D7 and PfCam3.IR539T with IC50 values of 9.24 ± 0.52 μg/mL and 17.41 ± 0.43 μg/mL, respectively. The RsMeOH crude extract exhibited moderate antiplasmodial activity while the RsHex fraction showed the least antiplasmodial activity. The GC-MS and FTIR analysis of RsMeOH and RsEA revealed the presence of triterpenes, phenols, and hydrocarbons as major constituents. The RsMeOH crude extract was non-hemolytic and non-cytotoxic to HeLa, HEK-293T, and MCF-7 cell lines. The in vivo studies showed that a 1200 mg/kg dose of RsMeOH crude extract could significantly suppress parasitemia by ∼63% and prolong the survival of treated mice by ∼10 days. The in vivo antiplasmodial activity of RsMeOH was better than the RsEA fraction.

CONCLUSION

The findings of this study demonstrated that traditionally used herbal medicinal plants like R. serrata provide a platform for the identification and isolation of potent bioactive phytochemicals that in turn can promote the antimalarial drug research. RsMeOH crude extract and RsEA fraction showed antiplasmodial, antimalarial and antioxidant activities. Chemical fingerprinting analysis suggested the presence of bioactive phytocompounds that are known for their antimalarial effects. Further detailed investigations on RsMeOH crude extract and RsEA fraction would be needed for the identification of the entire repertoire of the active antimalarial components with potent pharmaceutical and therapeutic values.

Indigenous medicinal plants used in folk medicine for malaria treatment in Kwara State, Nigeria: an ethnobotanical study

BACKGROUND

Folk medicine is crucial to healthcare delivery in the underdeveloped countries. It is frequently used as a primary treatment option or as a complementary therapy for malaria. Malaria is a deadly disease which greatly threatens global public health, claiming incredible number of lives yearly. The study was aimed at documenting the medicinal plants used for malaria treatment in folk medicine in Kwara State, Nigeria.

METHODS

Ethnobotanical information was collected from selected consenting registered traditional medicine practitioners (TMPs) through oral face-to-face interviews using in-depth, semi-structured interview guide. The ethnobotanical data were analysed, and descriptive statistical methods were used to compile them.

RESULTS

Sixty-two indigenous medicinal plants, including 13 new plants, used for malaria treatment were identified in this study. The TMPs preferred decoction in aqueous solvent (34%) and steeping in decaffeinated soft drink (19%) for herbal preparations. Oral administration (74%) was the main route of administration, while leaves (40%) and stem barks (32%) were the most dominant plant parts used in herbal preparations. The most cited families were Fabaceae (15%) and Rutaceae (6%), while Mangifera indica (77.14%), Enantia chlorantha (65.71%), Alstonia boonei (57.14%) followed by Cymbopogon citratus (54.29%) were the most used plants. Besides, the antimalarial activities of many of the plants recorded and their isolated phytocompounds have been demonstrated. Furthermore, the conservation status of 4 identified plants were Vulnerable.

CONCLUSION

The study showed strong ethnobotanical knowledge shared by the TMPs in the State and provides preliminary information that could be explored for the discovery of more potent antimalarial compounds.

Neopterin Levels in Bonobos Vary Seasonally and Reflect Symptomatic Respiratory Infections

As environmental changes exacerbate the threat coming from infectious diseases in wild mammal species, monitoring their health and gaining a better understanding of the immune functioning at the species level have become critically important. Neopterin is a biomarker of cell-mediated immune responses to intracellular infections. We investigated the variation of urinary neopterin (uNeo) levels of wild, habituated bonobos (Pan paniscus) in relation to individual and environmental factors. We used 309 urine samples collected between 2010 and 2018 at the LuiKotale field site, DRC. Based on current knowledge on zoo-housed conspecifics and closely related species, we predicted uNeo levels to increase (1) during infections, (2) with increasing age, (3) over the gestation period and in estrous females; and (4) to vary seasonally. Our results showed uNeo levels varied over a one-year period and increased in individuals showing respiratory symptoms. Contrary to chimpanzees, uNeo levels did not vary with age or female reproductive status, possibly due to our small sample size. Our study provides a baseline for a better understanding of bonobo's immunocompetence in the context of socio-ecological pressures and for monitoring the health of wild populations.

Phytochemical composition, bioactive properties, and toxicological profile of Tetrapleura tetraptera

The use of medicinal plants has gained renewed wide popularity in Africa, Asia, and most parts of the world because of the decreasing efficacy of synthetic drugs. Thus, natural products serve as a potent source of alternative remedy. Tetrapleura tetraptera is a medicinal plant with cultural and traditional significance in West Africa. In addition to the plant being commonly used as a spice in the preparation of traditional spicy food for postpartum care it is also widely used to constitute herbal concoctions and decoctions for treatment of diseases. This review aimed to provide an up-to-date information on the ethnomedicinal uses, pharmacological activities and phytoconstituents of T. tetraptera. Preclinical studies regarding the plant's toxicity profile were also reviewed. For this updated review, literature search was done on PubMed, Science Direct, Wiley, and Google Scholar databases using the relevant keywords. The review used a total of 106 papers that met the inclusion criteria from January 1989 - February 2022 and summarised the bioactivities that have been reported for the rich phytoconstituents of T. tetraptera studied using various chemical methods. Considering the huge report, the review focused on the antimicrobial and antiinflammatory activities of the plant extracts and isolated compounds. Aridan, aridanin and several bioactive compounds of T. tetraptera have shown pharmacological activities though their mechanisms of action are yet to be fully understood. This study also highlighted the influence of plant parts and extraction solvents on its biological activities. It also presented data on the toxicological profile of the plant extracts using different models. From cultural uses to modern pharmacological research the bioactive compounds of T. tetraptera have proved effective in infectious disease management. We hope that this paper provided a robust summary of the biological activities and toxicological profile of T. tetraptera, thus calling for more research into the pharmacological and pharmacokinetic activities of natural products to help combat the growing threat of drug resistance and provide guidelines for their ethnomedicinal uses.

A Review on Traditionally Used African Medicinal Plant Annickia chlorantha, Its Phytochemistry, and Anticancer Potential

Annickia chlorantha Setten & P.J.Maas belongs to the Annonaceae family and is a multi-purpose medicinal plant, which has been extensively used for the traditional treatment option for malaria in western and central Africa. Its phytochemical composition is dominated particularly by various biologically active protoberberines and acetogenins. This review aims to provide a comprehensive review on the traditional uses, phytochemical profiles, and the toxicology of this plant from a myriad of available publications. Even after its tremendous applications against several different human ailments, this plant has been underestimated for its anticancer potential. Herein, based on the phytochemical composition, we discuss the probable mode of mechanism for its antiproliferative activity, which highlights its importance for cytotoxicity screenings against cancer cells. Additionally, this article discusses several research questions and suggests the future directions of its applications in medicinal plant-based anticancer research.

Antitrypanosomal and Anthelminthic Properties of Ethanol Extracts of Carica papaya Linn. and Ceiba pentandra (L) Gaertn

The most common diseases that affect low-income countries are helminthosis and trypanosomosis. In Ghana, and in many other African countries, herbal treatment of various diseases is still common. In the present study, we sought to determine the antitrypanosomal and anthelminthic activities of Carica papaya and Ceiba pentandra. The ethanol extracts of Carica papaya stem bark (PPSe) and leaves (PPLe) and ethanol extracts of Ceiba pentandra stem bark (CPSe) and leaves (CPLe) were screened against Trypanosoma brucei brucei and Pheretima posthuma worms in vitro. CPSe exhibited strong antitrypanosomal activity, while the other extracts exhibited moderate activity against T. b. brucei. All the extracts showed weak selective indices (SI) when tested on Jurkat cell lines, which is indicative of a potential toxic effect. When the extracts were screened against P. posthuma worms, only PPSe and CPSe were able to kill the worms after the exposure time at concentrations of 2.5, 5, and 10 mg/mL. PPSe was again the only extract that potentiated the anthelminthic activity of albendazole against P. posthuma worms. Preliminary phytochemical screening and GC-MS analysis revealed the presence of compounds with antitrypanosomal and anthelminthic properties. The results confirmed the potential of C. papaya and C. pentandra as remedies for trypanosomosis and helminthosis and also gives credence to their folkloric use.

Effects of Berberine on Liver Cancer

Liver cancer, otherwise known as hepatocellular carcinoma, is a chronic disease condition with an excessive deposition and growth of malignant cells in the body. The high incidence and prevalence rates of liver cancer continue to be problems, as well as its poor prognosis and therapeutic limitations involving severe drug adverse reactions linked to the use of synthetic chemotherapeutic compounds. Continuous experimental studies, as well as utilization of pure herbal-based compounds, are essential towards finding more potent cures for liver cancer. Natural bioactive compounds, particularly alkaloids (eg, berberine), have been shown to be highly beneficial in the treatment of various diseases. Berberine (BBR), an isoquinoline alkaloid, is obtained from stem, bark, roots, rhizomes, and leaves of several medicinal plants, including Berberis species. It is commonly synthesized from the benzyltetrahydroisoquinoline system with the incorporation of an additional carbon atom as a bridge. The multiple attributes of BBR involving effective inhibitory and cytotoxic actions against the proliferation of cancer cells have been demonstrated. The use of BBR in experimental studies (in vivo and in vitro) for over a decade for liver cancer treatment has proven to be highly effective, safe, and potent. Until now, the poor solubility of BBR remains one of the contributing factors leading to its minimal clinical bioavailability. Therefore, BBR could serve as a prospective drug candidate in the future towards drug formulation for liver cancer treatment. The relevant information regarding this review was obtained electronically through the use of databases such as PubMed, Google Scholar, Springer, Hindawi, Embase, Web of Science, and China National Knowledge Infrastructure. All the aforementioned databases were searched from 1981 to 2020. This literature represents an update of previous review papers discussing the various positive pharmacological and mechanistic effects (oxidative stress regulation, inflammation reduction, apoptosis activation, overcoming drug resistance, and metastasis inhibition) of BBR for liver cancer treatment, which would be of great significance to drug development and clinical research.

Ethnopharmacological Study of Medicinal Plants Used for the Treatment of Cardiovascular Diseases and Their Associated Risk Factors in sub-Saharan Africa

Cardiovascular diseases (CVDs) are the leading cause of global mortality, including deaths arising from non-communicable diseases in sub-Saharan Africa (SSA). Consequently, this study aimed to provide details of medicinal plants (MPs) employed in SSA for the treatment of CVDs and their related risk factors to open new avenues for the discovery of novel drugs. The extensive ethnopharmacological literature survey of these MPs in 41 SSA countries was based on studies from 1982 to 2021. It revealed 1,085 MPs belonging to 218 botanical families, with Fabaceae (9.61%), Asteraceae (6.77%), Apocynaceae (3.93%), Lamiaceae (3.75%), and Rubiaceae (3.66%) being the most represented. Meanwhile, Allium sativum L., Persea americana Mill., Moringa oleifera Lam., Mangifera indica L., and Allium cepa L. are the five most utilised plant species. The preferred plant parts include the leaves (36%), roots (21%), barks (14%), fruits (7%), and seeds (5%), which are mostly prepared by decoction. Benin, Mauritius, Nigeria, South Africa, and Togo had the highest reported use while most of the investigations were on diabetes and hypertension. Despite the nutraceutical advantages of some of these MPs, their general toxicity potential calls for caution in their human long-term use. Overall, the study established the need for governments of SSA countries to validate the efficacy/safety of these MPs as well as provide affordable, accessible, and improved modern healthcare services.

Antimicrobial, antioxidant and antileishmanial activities of Ziziphus lotus leaves

The aim of this study was to investigate antimicrobial and antioxidant activities of different fractions obtained from edible Tunisian Ziziphus Lotus leaves of Tozeur region. Different organic extracts were tested: cyclohexane, dichloromethane, ethyl acetate, n-butanol and water. Bio-guided fractionation revealed that dichloromethane fraction is the most active against S. aureus and Methicillin-resistant S. aureus strains. Moreover, this fraction showed the highest antileishmanial activity with IC₅₀ values of 20.55 ± 0.34 μg/mL and 15.37 ± 0.17 μg/mL against L. major and L. infantum, respectively. The potentialities of antibacterial and leishmanicidal activities found in dichloromethane could be explained by the presence of major flavonoids such as catechin, rutin and luteolin 7-O-glucoside as revealed by HPLC system. The observed moderate antifungal activity, which was only given by butanolic fraction against pathogen fungi, may be attributed to the presence of chlorogenic acid. Furthermore, dichloromethane and butanolic fraction showed a good DPPH (2,2-diphenyl-1-picryl hydrazyl) scavenging activity and Ferric reducing power. These results suggest that Ziziphus lotus leaf fractions might be used as antioxidant and antimicrobialagent.

Antiplasmodial, antimalarial activities and toxicity of African medicinal plants: a systematic review of literature

BACKGROUND

Malaria still constitutes a major public health menace, especially in tropical and subtropical countries. Close to half a million people mainly children in Africa, die every year from the disease. With the rising resistance to frontline drugs (artemisinin-based combinations), there is a need to accelerate the discovery and development of newer anti-malarial drugs. A systematic review was conducted to identify the African medicinal plants with significant antiplasmodial and/or anti-malarial activity, toxicity, as wells as assessing the variation in their activity between study designs (in vitro and in vivo).

METHODS

Key health-related databases including Google Scholar, PubMed, PubMed Central, and Science Direct were searched for relevant literature on the antiplasmodial and anti-malarial activities of African medicinal plants.

RESULTS

In total, 200 research articles were identified, a majority of which were studies conducted in Nigeria. The selected research articles constituted 722 independent experiments evaluating 502 plant species. Of the 722 studies, 81.9%, 12.4%, and 5.5% were in vitro, in vivo, and combined in vitro and in vivo, respectively. The most frequently investigated plant species were Azadirachta indica, Zanthoxylum chalybeum, Picrilima nitida, and Nauclea latifolia meanwhile Fabaceae, Euphorbiaceae, Annonaceae, Rubiaceae, Rutaceae, Meliaceae, and Lamiaceae were the most frequently investigated plant families. Overall, 248 (34.3%), 241 (33.4%), and 233 (32.3%) of the studies reported very good, good, and moderate activity, respectively. Alchornea cordifolia, Flueggea virosa, Cryptolepis sanguinolenta, Zanthoxylum chalybeum, and Maytenus senegalensis gave consistently very good activity across the different studies. In all, only 31 (4.3%) of studies involved pure compounds and these had significantly (p = 0.044) higher antiplasmodial activity relative to crude extracts. Out of the 198 plant species tested for toxicity, 52 (26.3%) demonstrated some degree of toxicity, with toxicity most frequently reported with Azadirachta indica and Vernonia amygdalina. These species were equally the most frequently inactive plants reported. The leaves were the most frequently reported toxic part of plants used. Furthermore, toxicity was observed to decrease with increasing antiplasmodial activity.

CONCLUSIONS

Although there are many indigenous plants with considerable antiplasmodial and anti-malarial activity, the progress in the development of new anti-malarial drugs from African medicinal plants is still slothful, with only one clinical trial with Cochlospermum planchonii (Bixaceae) conducted to date. There is, therefore, the need to scale up anti-malarial drug discovery in the African region.

What fecal analyses reveal about Manniophyton fulvum consumption in LuiKotale bonobos (Pan paniscus): A medicinal plant revisited

Observations of animals in the wild can result in the discovery of plants for human medicinal purposes. In this context, our closest relatives, the great apes, are of particular interest. The Euphorbiaceae Manniophyton fulvum possesses both phytochemical and biomechanical properties. Its use in the genus Pan (P. troglodytes; P. paniscus) is thought to be based on its mechanical properties promoting the egestion of intestinal parasites, but additional observations from different habitats where the behavior is performed may shed more light on its true purpose. To improve our understanding of what triggers this behavior, we investigated M. fulvum consumption in wild bonobos at LuiKotale, Democratic Republic of the Congo between December 2018 and July 2020. Specifically, we tested the hypothesis that M. fulvum ingestion is related to gastro-intestinal parasite expulsion. Of 649 focal follows of 37 individuals from two habituated communities, consumption of M. fulvum was observed on 111 days (N = 507), independent of seasons, environmental factors and the plant's availability. A total of 588 fecal samples were assessed for the presence/absence of gastro-intestinal parasites. We found strongyle eggs in 2.89% of samples and their presence was not associated with the ingestion of M. fulvum or environmental conditions. We discuss the importance of seasonality in the life cycle of strongyle species that may influence the pattern of M. fulvum consumption observed at LuiKotale. Our data open additional perspectives concerning behavioral parameters such as the existence of a cultural component when comparing ingestion behavior between communities.

Nutmegs and wild nutmegs: An update on ethnomedicines, phytochemicals, pharmacology, and toxicity of the Myristicaceae species

Prized medicinal spice true nutmeg is obtained from Myristica fragrans Houtt. Rest species of the family Myristicaceae are known as wild nutmegs. Nutmegs and wild nutmegs are a rich reservoir of bioactive molecules and used in traditional medicines of Europe, Asia, Africa, America against madness, convulsion, cancer, skin infection, malaria, diarrhea, rheumatism, asthma, cough, cold, as stimulant, tonics, and psychotomimetic agents. Nutmegs are cultivated around the tropics for high-value commercial spice, used in global cuisine. A thorough literature survey of peer-reviewed publications, scientific online databases, authentic webpages, and regulatory guidelines found major phytochemicals namely, terpenes, fatty acids, phenylpropanoids, alkanes, lignans, flavonoids, coumarins, and indole alkaloids. Scientific names, synonyms were verified with www.theplantlist.org. Pharmacological evaluation of extracts and isolated biomarkers showed cholinesterase inhibitory, anxiolytic, neuroprotective, anti-inflammatory, immunomodulatory, antinociceptive, anticancer, antimicrobial, antiprotozoal, antidiabetic, antidiarrhoeal activities, and toxicity through in-vitro, in-vivo studies. Human clinical trials were very few. Most of the pharmacological studies were not conducted as per current guidelines of natural products to ensure repeatability, safety, and translational use in human therapeutics. Rigorous pharmacological evaluation and randomized double-blind clinical trials are recommended to analyze the efficacy and therapeutic potential of nutmeg and wild nutmegs in anxiety, Alzheimer's disease, autism, schizophrenia, stroke, cancer, and others.

Anti-trypanosomal and anthelminthic properties of ethanol and aqueous extracts of Tetrapleura tetraptera Taub

Trypanosomosis and helminthosis, considered as part of neglected tropical diseases, are parasitic infections of public health importance, especially in Africa. Medicinal plants have been used in most parts of Africa, to treat these parasitic infections. The study aims to determine the anti-trypanosomal and anthelminthic properties of Tetrapleura tetraptera (fruit and stembark). The aqueous extracts of T. tetraptera fruit (TTFaq) and stembark (TTSaq), as well as ethanol extracts of T. tetraptera fruit (TTFe) and stembark (TTSe), were screened for their in vitro anti-trypanosomal and anthelminthic activities against T. b. brucei and Pheretima posthuma worms, respectively. Preliminary phytochemical screening of all extracts and gas chromatography-mass spectrometry (GC-MS) analysis of most active extracts were conducted. TTFaq exhibited anti-trypanosomal activity with IC₅₀ of 18.18 μg/mL. TTSe and TTFe had moderate anti-trypanosomal activity with IC₅₀ of 34.76 and 34.84 μg/mL, respectively. TTSaq had relatively low activity against the parasite with IC₅₀ of 55.03 μg/mL. The SI of T. tetraptera extracts was between the range of 0.14-2.09. TTFaq showed dose-dependent activity causing paralysis and death of the adult worms at all concentrations. At the least concentration of 0.625 mg/mL, TTFaq induced paralysis and death after 101.88 ± 0.8 and 242.64 ± 0.38 min of exposure, respectively compared with the negative control (p < 0.0001). TTFe, TTSe and TTSaq caused paralysis of worms after 318.32 ± 0.74, 422.5 ± 0.72, 422.20 ± 0.55 min of exposure at minimum concentrations of 2.5, 10 and 5 mg/mL, respectively (p < 0.0001). However, no death was observed in worms treated with TTFe, TTSe and TTSaq at all test concentrations. In the presence of sub-minimal inhibitory concentration of the extracts, TTFaq potentiated the anthelminthic activity of albendazole whiles TTFe, TTSaq and TTSe inhibited the activity of albendazole. Phytochemical screening revealed the presence of saponins, triterpenoids, reducing sugars, flavonoids (absent in TTFe), steroids (absent in TTFaq) and tannins (absent in TTSe and TTFe) in the extracts. GC-MS revealed the presence of 9-octadecenamide and betulic acid in TTFaq. Hence, there was evidence provided here that Tetrapleura tetraptera may be effective. This gives credence to their folkloric use. However, further study might be necessary to ascertain safety use in both humans and animals.

Anticancer activity of Nigerian medicinal plants: a review

Background

Cancer is currently the leading cause of death globally and the number of deaths from cancer is on the rise daily. Medicinal plants have been in continuous use over the years for the management of cancer, particularly, in most developing countries of the world including Nigeria. The use of synthetic drugs for the treatment of cancer is often accompanied by toxic side effects. Thus, the alternative use of readily available and inexpensive medicinal plants is the panacea to the toxic side effects associated with synthetic drugs.

Main body

The present review summarized the anticancer activity of 51 medicinal plants that are widespread in all regions of Nigeria. Furthermore, the proposed anticancer pharmacological actions as well as the anticancer bioactive compounds, the type of cancer cell inhibited, the plant parts responsible for the anticancer activity, and the nature of the extracts used for the studies were discussed in this review. The 51 Nigerian medicinal plants were reported to exhibit anticancer activities of the prostate, cervices, lung, skin, colon, esophagus, blood, ovary, central nervous system/brain, breast, stomach, pancreas, larynx, and kidney. The major classes of bioactive compounds indicated to be responsible for the anticancer activity include the polyphenols, flavonoids, alkaloids, saponins, triterpenes, tannins, and quinones. The major anticancer pharmacological actions of these bioactive compounds were antiproliferative, cytotoxic, cytostatic, antimetastatic, apoptotic, and antioxidative as well as provoked cell cycle arrest, inhibition of angiogenesis and reduction of cancer cell viability.

Conclusion

The Nigerian medicinal plants can be harnessed to provide for readily available and inexpensive anticancer drugs in the future because the plants reported in this review showed promising anticancer activity.

Afrostyrax lepidophyllus Mildbr. and Monodora myristica (Gaertn.) Dunal Extracts Decrease Doxorubicin Cytotoxicity on H9c2 Cardiomyoblasts

Materials and Methods

Bark extracts of these plants (1 and 25 µg/mL) were added 3 hours before coincubating H9c2 cardiomyoblasts with Dox (0.5 and 1 µM) for 24 hours more. We measured cell mass and metabolic viability, mitochondrial transmembrane potential, superoxide anion content, and activity-like of caspase-3 and caspase-9 following treatment with the extracts and/or Dox. Also, selenium and vitamin C contents were measured in the plant extracts.

Results

The results confirmed that Dox treatment decreased cell mass, mitochondrial membrane potential and metabolic viability, increased mitochondrial superoxide anion, and stimulated caspase-3 and caspase-9-like activities. Pretreatment of the cells with the plant extracts significantly inhibited Dox cytotoxicity, with more significant results at the higher concentration. Measurements of selenium and vitamin C in the extracts revealed higher concentration of both when compared with other Cameroonian spices.

Conclusion

Both extracts of A. lepidophyllus and M. myristica were effective against Dox-induced cytotoxicity, most likely due to their content in antioxidants.

Geopolitics of bitterness: Deciphering the history and cultural biogeography of Quassia amara L

ETHNOPHARMACOLOGICAL RELEVANCE

Quassia amara L. recently came into the spotlight in French Guiana, when it became the object of a biopiracy claim. Due to the numerous use records throughout the Guiana shield, at least since the 18th century, a thorough investigation of its origin seemed relevant and timely. In the light of the Convention on Biological Diversity (CBD) and the Nagoya protocol, questions about the origin of local knowledge are important to debate.

AIM OF THE STUDY

Defining cultural biogeography as the dynamics through space and time of biocultural complexes, we used this theoretical framework to shed light on the complex biogeographical and cultural history of Q. amara. We explored in particular the possible transfer of medicinal knowledge on an Old World species to a botanically related New World one by enslaved Africans in Suriname.

MATERIALS AND METHODS

Historical and contemporary literature research was performed by means of digitized manuscripts, archives and databases from the 17th to the 21st century. We retrieved data from digitized herbarium vouchers in herbaria of the Botanic Garden Meise (Belgium); Naturalis Biodiversity Center (the Netherlands); Missouri Botanical Garden, the Smithsonian National Museum of Natural History, the Field Museum (USA); Royal Botanic Gardens Kew (UK); the IRD Herbarium, French Guiana and the Museum National d'Histoire Naturelle (France). Vernacular names were retrieved from literature and herbarium specimens and compared to verify the origin of Quassia amara and its uses.

RESULTS

Our exploration of digitized herbarium vouchers resulted in 1287 records, of which 661 were Q. amara and 636 were Q. africana. We observed that the destiny of this species, over at least 300 years, interweaves politics, economy, culture and medicine in a very complex way. Quassia amara's uses are difficult to attribute to specific cultural groups: the species is widely distributed in Central and South America, where it is popular among many ethnic groups. The species spread from Central to South America during the early 18th century due to political and economic reasons. This migration possibly resulted from simultaneous migration by religious orders (Jesuits) from Central America to northern South America and by Carib-speaking Amerindians (from northern South America to Suriname). Subsequently, through colonial trade networks, Q. amara spread to the rest of the world. The absence of African-derived local names in the Guiana shield suggests that Q. africana was not sufficiently familiar to enslaved Africans in the region that they preserved its names and transferred the associated medicinal knowledge to Q. amara.

CONCLUSIONS

Cultural biogeography has proven an interesting concept to reconstruct the dynamics of biocultural interactions through space and time, while herbarium databases have shown to be useful to decipher evolution of local plant knowledge. Tracing the origin of a knowledge is nevertheless a complex adventure that deserves time and interdisciplinary studies.

Phytochemical profiling of aqeous methanolic leaf extract of Triclisia gilletii by gas chromatography (GC/MS) and liquid chromatography (HPLC-PDA-ESI/MSn) tandem mass spectroscopy (MS): a pointer to its nephroprotection

The phytochemical constituents in the aqueous methanolic leaf extract of Triclisia gilletii responsible for its nephroprotective potentials against ethane-1,2-diol induced nephrolithiasis as previously investigated in our laboratory were elucidated. The extract was prepared using 80% aqueous methanol in 72 h, Phytochemical contents of aqueous methanolic extract of Triclisia gilletii (TGME) was identified using both a Thermo Scientific DSQII single quadrupole gas chromatography (GC) and a Thermo Scientific liquid chromatography (LCQ Fleet system) tandem mass spectroscopy. The chromatogram acquisition, detection of mass spectral peaks and their waveform processing were performed using Xcalibur MS Software (Thermo Scientific Inc.). GC-MS analysis revealed the presence of phenols, fatty acids, vitamins and steroids. Likewise, for LC-MS analysis kaempferol and dihydrovomifoliol-O-glucoside were detected. The identified constituents have possible contributively effect on the acclaimed pharmacological potential of Triclisia gilletii against ethane-1,2-diol induced nephrolithiasis.

Manniindole, an indole derivative from the roots of Anonidium mannii and combined antischistosomal and enzymatic activities

A new alkaloid, manniindole 1, together with four known compounds: aristolactam AII 2, aristolactam BII 3, piperolactam D 4 and polycarpol 5 were isolated from the crude extract EtOH-H₂O (8:2) of the roots of Anonidium mannii by chromatographic separation. The structure elucidation was performed on the basis of a spectroscopic analysis (IR, HRESI MS, 1D and 2D NMR) as well as a comparison of their spectral data with those reported in the literature. For the first time, the crude extract and those isolated compounds were evaluated for their anti-schistosomal activity against Schistosoma mansoni and for cytotoxicity activity against Huh7 and A549 cells. Furthermore, they were also tested in vitro on the recent characterized Schistosoma mansoni NAD⁺ catabolizing enzyme (SmNACE) for their impact on this enzyme which is localized on the outer surface of the adult parasite. Compound 2 displayed quite good worm killing capability, while 4 showed significant inhibition of SmNACE.

Use of herbal remedies in the management of sleeping sickness in four northern provinces of Angola

ETHNOPHARMACOLOGICAL RELEVANCE

This study reports for the first time on the use of folk medicine to treat sleeping sickness and its symptoms in four endemic provinces in northern Angola. By interviewing both traditional practitioners and confirmed patients, it highlights reasons to recourse to folk medicine, the plant species used for this affection as well as arises awareness about the use of particular plants showing potential risks.

AIM OF THE STUDY

The aims of this explorative study were three-fold. Firstly, it informed on access to, and use of plant-based medicine as first-choice treatment by infected persons. Secondly, it aimed at collecting comprehensive data from patients and traditional healers on herbal remedies in order to identify plant species used in the management of the disease. Thirdly, it served as contribution for primary indication of potential risk of use associated with the studied plants and their preparation.

MATERIALS AND METHODS

The study was conducted in 4 endemic provinces of Angola, namely Bengo, Zaire, Kwanza Norte and Uíge. We explored the use of herbal remedies by conducting structured and semi-structured interviews within two distinct study populations. The first group comprises 30 patients who had been diagnosed for trypanosomiasis and treated by the reference treatment. The second group included 9 traditional practitioners who had already treated sleeping sickness. The plants that were cited during the interviews were collected during field walks under supervision of a traditional healer, then authenticated and deposited at the National Herbarium in Luanda.

RESULTS

Of the 30 included patients, 12 (40%) had turned to folk medicine in the management of trypanosomiasis and related symptoms. 7 medicinal plants were reported by this group. Considering the key motivation to consult a traditional practitioner, two main factors accounted for half of the cases: "past experience with folk medicine" and "family habit". Out of 9 traditional practitioners' interviewees, 26 medicinal plants were cited. Roots and leaves were the most used plant parts, and decoction was the common mode of preparation. Evidence for antitrypanosomal activity in the scientific literature was found for 56% (17 of 30) of the identified plant species. The most cited plant was Crossopteryx febrifuga (UR = 6). Some of the cited plants, as for example Aristolochia gigantea, raised concern about potential toxicity.

CONCLUSIONS

With 40% of infected persons having turned first to folk medicine before consulting a medical doctor, this explorative study points out that plant-based medicines play an important role in local dynamics of health care. It highlights the need for primary assessment of potential risk of use related to the herbal recipes, and for reporting it to the concerned population. This first ethnobotanical study on trypanosomiasis in endemic provinces of Angola provides information on 30 plants, of which some had been identified as promising for further pharmacological research. Our results provide a first step towards the validation and valorization of Angolan herbal remedies for sleeping sickness.

Compound isolation and biological activities of Piptadeniastrum africanum (hook.f.) Brennan roots

ETHNOPHARMACOLOGICAL RELEVANCE

The dicotyledonous plant Piptadeniastrum africanum (hook.f.) Brennan (Fabaceae) is used in traditional medicine to treat various human complaints including bronchitis, coughing, urino-genital ailments, meningitis, abdominal pain, treatment of wounds, malaria and gastrointestinal ailments, and is used as a purgative and worm expeller.

AIM OF THE STUDY

The present study describes the phytochemical investigation and the determination of the antimicrobial, antiplasmodial and antitrypanosomal activities of crude extract, fractions and compounds extracted from Piptadeniastrum africanum roots.

MATERIALS AND METHODS

Isolated compounds were obtained using several chromatographic techniques. The structures of all compounds were determined by comprehensive spectroscopic analyses (1D and 2D NMR) and by comparing their NMR data with those found in literature. In vitro antimicrobial activity of samples was evaluated using the microdilution method on bacterial (Escherichia coli, Proteus mirabilis, Staphylococcus aureus) and fungal (Candida krusei) strains, while in vitro cell-growth inhibition activities were assessed against two parasites (Trypanosoma brucei brucei and Plasmodium falciparum strain 3D7). The cytotoxicity properties of samples were assayed against HeLa human cervical carcinoma.

RESULTS

Five compounds were isolated and identified as: tricosanol 1, 5α-stigmasta-7,22-dien-3-β-ol 2, betulinic acid 3, oleanolic acid 4 and piptadenamide 5. This is the first report of the isolation of these five compounds from the roots of P. africanum. The (Hex:EtOAc 50:50) fraction exhibited moderate antibacterial activity against P. mirabilis (MIC 250 μg/mL), while the other fractions and isolated compounds had weak antimicrobial activities. Only the EtOAc fraction presented a moderate antimalarial activity with an IC50 of 16.5 μg/mL. The MeOH crude extract and three fractions (Hexane, Hexane-EtOAc 25% and EtOAc-MeOH 25%) exhibited significant trypanocidal activity with IC50 values of 3.0, 37.5, 3.8 and 9.5 μg/mL, respectively.

CONCLUSION

These results demonstrated a scientific rational of the traditional uses of P. africanum and indicate that this plant should be further investigated to identify some of the chemical components that exhibited the activities reported in this study and therefore may constitute new lead candidates in parasiticidal drug discovery.

Microalgae extracts: Potential anti-Trypanosoma cruzi agents?

INTRODUCTION

Chagas disease, caused by the protozoan parasiteTrypanosoma cruzi, has no effective treatment available. On the other hand, microalgae are aquatic organisms that constitute an interesting reservoir of biologically active metabolites. Moreover, some species of green and red algae present anti-protozoan activity. Our aim was to study the antiparasitic effects of aqueous, methanolic and ethanolic extracts from different microalgae.

METHODS AND RESULTS

Our results show that the methanolic extracts of S. obliquus and T. suecica as well as the ethanolic extracts of C. reinhardtii and T. suecica present trypanocidal activity on the infective extracellular trypomastigotes and intracellular amastigotes. In addition, the ethanolic extract of C. reinhardtii potentiates the activity of the conventional antichagasic drug nifurtimox. In order to identify some potential compounds with trypanocidal activity, we performed a phytochemical screening analyzing the presence of phenolic compounds, pigments and terpenoids.

CONCLUSION

The different microalgae extracts, particularly the ethanolic extract ofC. reinhardtii, are promising potential candidates for the development of future natural antichagasic drugs.

Evaluation of Pharmacological and Phytochemical Profiles Piptadeniastrum africanum (Hook.f.) Brenan Stem Bark Extracts

The stem bark (SB) of Piptadeniastrum africanum (PA) has been extensively used in African traditional medicinal systems. However, there is a dearth of scientific information regarding its possible activity in the management of type II diabetes, Alzheimer’s disease, and skin hyperpigmentation disorders. This study therefore attempted to elucidate the in vitro inhibitory action of ethyl acetate, methanol, and water extracts of P. africanum stem bark (PA-SB) on α-amylase, α-glucosidase, acetylcholinesterase, butyrylcholinesterase, and tyrosinase. Cell viability, catecholamine, and 3-hydroxykynurenine levels of hypothalamic HypoE22 cells exposed to PA-SB extracts were also investigated. The phytochemical profiles of the extracts were determined by high performance liquid chromatography (HPLC) and antioxidant properties were investigated. Saponin (867.42 mg quillaja equivalent/g) and tannin (33.81 mg catechin equivalent/g) contents were higher in the methanol extract. Multiple dihydroxy-trimethoxy(iso)flavone isomers, loliolide, eriodictyol, naringenin, luteolin, chrysoeriol, apigenin, and liquiritigenin, were characterized from PA-SB extracts using HPLC. The methanol extract of PA-SB showed highest inhibitory activity against acetylcholinesterase (4.88 mg galantamine equivalent (GALAE)/g extract), butyrylcholinesterase (5.37 mg GALAE/g extract), and tyrosinase (154.86 mg kojic acid equivalent/g extract) while α-glucosidase was effectively inhibited by the ethyl acetate extract (15.22 mmol acarbose equivalent/g extract). The methanol extract of PA-SB also showed potent antioxidant properties (493.87, 818.12, 953.07, and 732.19 mg Trolox equivalent/g extract, for 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS), cupric reducing antioxidant capacity (CUPRAC), and ferric reducing antioxidant power (FRAP) assays, respectively). PA-SB extracts exhibited antioxidant activity and promising inhibition against key enzymes related to type II diabetes, Alzheimer’s disease, and skin hyperpigmentation disorders. Additionally, all extracts were able to contrast hydrogen peroxide-induced oxidative stress, in HypoE22 cells, thus restoring basal catecholamine and 3-hydroxykinurenine levels, whereas only methanol and water extracts stimulated basal dopamine release. Overall, data from the present study contribute to the biological assessment of P. africanum that appears to be a promising source of natural compounds with protective and neuromodulatory effects.

Antimalarial herbal remedies of Bukavu and Uvira areas in DR Congo: An ethnobotanical survey

ETHNOPHARMACOLOGICAL RELEVANCE

The main objective of the present study was to collect and gather information on herbal remedies traditionally used for the treatment of malaria in Bukavu and Uvira, two towns of the South Kivu province in DRC.

MATERIAL AND METHODS

Direct interview with field enquiries allowed collecting ethnobotanical data; for each plant, a specimen was harvested in the presence of the interviewed traditional healers (THs). The recorded information included vernacular names, morphological parts of plants, methods of preparation and administration of remedies, dosage and treatment duration. Plants were identified with the help of botanists in the herbaria of INERA/KIPOPO (DRC) and the Botanic Garden of Meise (Belgium), where voucher specimens have been deposited. The results were analysed and discussed in the context of previous published data.

RESULTS

Interviewees cited 45 plant species belonging to 41 genera and 21 families used for the treatment of malaria. These plants are used in the preparation of 52 recipes, including 25 multi-herbal recipes and 27 mono-herbal recipes. Apart of Artemisia annua L. (Asteraceae; % Citation frequency = 34%) and Carica papaya L. (Caricaceae; % Citation frequency = 34%), the study has highlighted that the most represented families are Asteraceae with 12 species (26%), followed by Fabaceae with 7 species (16%) and Rubiaceae with 4 species (9%). For a majority of plants, herbal medicines are prepared from the leaves in the form of decoction and administered by oral route.

CONCLUSION

Literature data indicate that part of cited species are already known (38%) and/or studied (30%) for antimalarial properties, which gives credit to the experience of Bukavu and Uvira interviewees and some level of confidence on collected information. The highly cited plants should be investigated in details for the isolation and identification of active ingredients, a contribution to the discovery of new possibly effective antimalarials.

Bioactivity and modulatory functions of Napoleona vogelii on oxidative stress-induced micronuclei and apoptotic biomarkers in mice

Napoleona vogelii is used in traditional medicine for the management of pain, inflammatory conditions and cancer. This study was conducted to investigate the modulatory mechanisms of methanol stem bark extract of N. vogelii on induction of micronuclei, apoptotic biomarkers and in vivo antioxidant enzymes in mice. Forty male albino mice were randomly divided into eight groups (n = 5) and were administered distilled water (DW, 5 mL/kg) as negative control, 100, 200 or 400 mg/kg of the extract respectively for 28 days before the injection of cyclophosphamide (CP, 40 mg/kg) i.p. on the 28th day. The remaining groups were administered 100, 200 or 400 mg/kg of the extract only for 28 days. Twenty four hours after injection of CP or administration of the last dose of extract, animals were euthanized by cervical dislocation and blood samples collected for determination of in vivo antioxidants, the spleen harvested for immunohistochemical expression of NFκB, Bcl-2, Bax and p53. Bone marrow smears were also made for the micronucleus assay. Treatment with the extract resulted in a significant (p < 0.0001) reduction in frequency of micronucleated polychromatic erythrocytes (MNPCEs) compared to CP exposed control conferring protection of 75.09, 94.74 and 96.84% at 100, 200 or 400 mg/kg respectively. In extract and CP exposed animals, there were significant (p < 0.05) increases in GSH, GST and SOD with a corresponding significant (p < 0.05) reduction in MDA. In addition, the extract significantly downregulated cytoplasmic levels of NFκB and Bcl-2 and upregulated Bax and p53. These findings demonstrate that N. vogelli may serve as an interesting lead for chemo-preventive drug development.

Antioxidant and prooxidant effects of Piptadeniastrum africanum as the possible rationale behind its broad scale application in African ethnomedicine

ETHNOPHARMACOLOGICAL RELEVANCE

Piptadeniastrum africanum is widely used in treating oxidative stress related diseases. Oxidative stress, defined as the disturbance in the balance between the production of free radicals and antioxidant defenses, is the root cause of many pathophysiological conditions. Based on the dual properties of prooxidants as toxic and beneficial compounds, both prooxidants and antioxidants may be effective in the treatment of these conditions when the right dose is given to the right subject at the right time for the right duration.

AIM OF THE STUDY

This study was aimed at investigating the in vitro and ex vivo anti- and pro-oxidative effects of P. africanum.

MATERIALS AND METHODS

Total phenolic and flavonoid contents of methanol and aqueous extracts of P. africanum stem back were quantified spectrophotometrically. The methanol extract, ascorbate radicals and reactive oxygen species in brain and liver homogenates of mice treated with the methanol stem bark extract were analyzed by electron paramagnetic resonance (EPR) spectroscopy. Free radical scavenging of DPPH was determined by spectrophotometric and EPR assays.

RESULTS

The methanol extract was richer in both phenolic and flavonoid contents compared to the aqueous extracts and also showed better DPPH radical scavenging capacity. The EPR spectroscopy in vitro analysis exhibited high DPPH scavenging capacity before and after UV irradiation (99.5% and 98.76%) at 40 μg/ml extract. The ex vivo EPR spectroscopy studies demonstrated increased levels of ascorbate radicals (•Asc) in liver and brain homogenates of healthy mice treated with P. africanum in comparison with those of the non treated controls (0.6141 ± 0.026 vs 0.1800 ± 0.0073 arb. units for liver homogenates and 0.9605 ± 0.0492 vs 0.3375 ± 0.0062 arb. units for brain homogenates, correspondingly). Considerably, higher levels of reactive oxygen species (ROS) were measured in mice liver and brain homogenates after treatment with P. africanum extract compared to the control group, as well (1.9402 ± 0.1200 vs 0.6699 ± 0.062 arb. units for liver homogenates and 1.7325 ± 01503 vs 0.3167 ± 0.0403 arb.units, respectively).

CONCLUSION

Therefore, P. africanum exhibited antioxidant and pro-oxidant properties which may explain its broad spectrum use in a wide variety of ailments.

Berberine: Botanical Occurrence, Traditional Uses, Extraction Methods, and Relevance in Cardiovascular, Metabolic, Hepatic, and Renal Disorders

Berberine-containing plants have been traditionally used in different parts of the world for the treatment of inflammatory disorders, skin diseases, wound healing, reducing fevers, affections of eyes, treatment of tumors, digestive and respiratory diseases, and microbial pathologies. The physico-chemical properties of berberine contribute to the high diversity of extraction and detection methods. Considering its particularities this review describes various methods mentioned in the literature so far with reference to the most important factors influencing berberine extraction. Further, the common separation and detection methods like thin layer chromatography, high performance liquid chromatography, and mass spectrometry are discussed in order to give a complex overview of the existing methods. Additionally, many clinical and experimental studies suggest that berberine has several pharmacological properties, such as immunomodulatory, antioxidative, cardioprotective, hepatoprotective, and renoprotective effects. This review summarizes the main information about botanical occurrence, traditional uses, extraction methods, and pharmacological effects of berberine and berberine-containing plants.

In vitro antiprotozoan activity and mechanisms of action of selected Ghanaian medicinal plants against Trypanosoma, Leishmania, and Plasmodium parasites

Trypanosomiasis, leishmaniasis, and malaria are protozoan infections of public health importance with thousands of new cases recorded annually. Control of these infection(s) with existing chemotherapy is limited by drug toxicity, lengthy parenteral treatment, affordability, and/or the emergence of resistant strains. Medicinal plants on the other hand are used in the treatment of various infectious diseases although their chemical properties are not fully evaluated. In this study, we screened 112 crude extracts from 72 selected Ghanaian medicinal plants for anti-Trypanosoma, anti-Leishmania, and anti-Plasmodium activities in vitro and investigated their mechanisms of action. Twenty-three extracts from 20 plants showed significant antiprotozoan activity against at least 1 of 3 protozoan parasites screened with IC₅₀ values less than 20 μg/ml. Eleven extracts showed high anti-Trypanosoma activity with Bidens pilosa whole plant and Morinda lucida leaf extracts recording the highest activities. Their IC₅₀ (selectivity index [SI]) values were 5.51 μg/ml (35.00) and 5.96 μg/ml (13.09), respectively. Nine extracts had high anti-Leishmania activity with Annona senegalensis and Cassia alata leaf extracts as the most active. Their IC₅₀ (SI) values were 10.8 μg/ml (1.50) and 10.1 μg/ml (0.37), respectively. Six extracts had high anti-Plasmodium activity with the leaf and stem-bark extracts of Terminalia ivorensis recording the highest activity. Their IC₅₀ (SI) values were 7.26 μg/ml (129.36) and 17.45 μg/ml (17.17), respectively. Only M. lucida at 25 μg/ml induced significant apoptosis-like cell death in Trypanosoma parasites. Anti-Leishmania active extracts induced varying morphological changes in Leishmania parasites such as multiple nuclei and/or kinetoplast, incomplete flagella division, or nuclear fragmentation. Active extracts may be potential sources for developing new chemotherapy against these infections.

Leishmanicidal and cytotoxic activity from plants used in Tacana traditional medicine (Bolivia)

ETNOPHARMACOLOGICAL RELEVANCE

Thirty-eight Tacana medicinal plant species used to treat skin problems, including leishmania ulcers, skin infections, inflammation and wound healing, were collected in the community of Buena Vista, Bolivia, with the Tacana people. Twenty two species are documented for the first time as medicinal plants for this ethnic group living in the northern area of the Department of La Paz.

AIM OF THE STUDY

To evaluate the leishmanicidal effect (IC₅₀) and cytotoxicity (LD₅₀) of the selected plants. To carry out bioguided studies on the active extracts. To assess the potential of Bolivian plant biodiversity associated with traditional knowledge in the discovery of alternative sources to fight leishmaniasis.

MATERIALS AND METHODS

Seventy three ethanol extracts were prepared from 38 species by maceration and were evaluated in vitro against promastigotes of Leishmania amazonensis and L. braziliensis. Active extracts (IC₅₀ ≤ 50 μg/mL) were fractionated by chromatography on Silica gel column and the fractions were assessed against the two Leishmania strains. The most active fractions and the crude extracts were evaluated against reference strains of L. amazonensis, L. braziliensis, L. aethiopica, two native strains (L. Lainsoni and L. braziliensis) and for cytotoxicity against HeLa cells. The chromatographic profile of the active fractions was obtained by reverse phase chromatography using HPLC.

RESULTS

From the 73 extracts, 39 extracts (53.4%) were inactive and 34 showed activity. Thirteen species were sselected for bioguided studies. The crude extracts and their 36 fractions were evaluated against two Leishmania strains. The most active fraction were tested in a panel of five leishmania strains and for cytotoxicity. The Selective Index (SI = LD₅₀/IC₅₀) was calculated, and were generally low. Retention time and UV spectra were recorded for the active fractions by HPLC-DAD using a reverse phase column. Profiles were very different from each other, showing the presence of different compounds.

CONCLUSION

Bolivian traditional knowledge from the Tacanba was useful to identify plants with effect on Leishmania promastigotes. Chromatographic bioguided studies showed stronger leishmanicidal and cytotoxic activity for the medium polar fraction. HPLC analysis showed different chromatographic profiles of the active fractions.

Biochemical, hematological, and hormonal profile of rats orally administered methanol stem bark extract of Napoleona vogelii Hook and Planch (Lecythidaceae)

Napoleona vogelii is used in traditional medicine for the management of stomach aches, ulcer, and cancers. This study was conducted to investigate the subchronic toxicological effect of methanol stem bark extract of N. vogelii on biochemical, hematological, and hormonal profile of male and female rats. Forty rats of both sexes were randomly divided into four groups of 10 rats each and were administered 100, 200, and 400 mg/kg of the extract p.o. for 90 d. Ten milliliter per kilogram of distilled water p.o. was administered to control rats. On hematological assessment, mean corpuscular hemoglobin concentration was significantly (p < 0.01) increased at 400 mg/kg compared to control. Biochemical assessment showed a significant increase (p < 0.05) in levels of alanine aminotransferase and aspartate aminotransferase at 200 and 400 mg/kg, respectively, compared to control. Hormonal assessment of male rats revealed a significantly (p < 0.0001) reduced level of testosterone at all treatment doses compared to control while estradiol was significantly (p < 0.05) reduced at 100 mg/kg, but significantly (p < 0.0001) increased at 200 and 400 mg/kg respectively compared to control in female rats. Findings from this study demonstrate that N. vogelli is relatively safe on oral acute exposure but may possess the potential to cause hepatic dysfunction and infertility in male rats by perturbations of the hypothalamic-pituitary axis while conversely enhancing fertility in female rats on subchronic administration.

Antigenotoxic and Antioxidant Activity of Methanol Stem Bark Extract of Napoleona Vogelii Hook & Planch (Lecythidaceae) In Cyclophosphamide-Induced Genotoxicity

BACKGROUND:

Napoleona vogelii is used in traditional medicine for cancer management.

AIM:

The study was conducted to evaluate the antigenotoxic and antioxidant activities of methanol stem bark extract of N. vogelii in male Sprague Dawley rats.

MATERIALS AND METHOD:

Thirty male Sprague Dawley rats were randomly divided into group 1 (control) administered 10 mL/kg distilled water, groups 2 and 3 were co-administered 100 mg/kg, 200 mg/kg of N. vogelli and 5 mg/kg cyclophosphamide (CPA) respectively for 7 days p.o. Groups 4 and 5 were administered only 5 mg/kg CPA and 200 mg/kg NV respectively.

RESULTS:

The LD50 oral was greater than 4 g/kg. There were significant (p < 0.0001) increases in plasma enzymatic and non-enzymatic antioxidant enzymes and significant (p < 0.0001) decrease in percentage micronuclei in bone marrow of extract treated rats compared to rats administered 5 mg/kg CPA alone. There was steatosis pointing to cytotoxic injury in the liver of rats co-administered 200 mg/kg NV and 5 mg/kg CPA. Gas chromatography-mass spectrometry analysis of the extract showed the presence of phytol and unsaturated fatty acids.

CONCLUSION:

N. vogelii possesses antigenotoxic and antioxidant activities associated with the presence of phytochemicals, phytol and unsaturated fatty acids.

In vitro antileishmanial activity of Mexican medicinal plants

Aim of the study

To evaluate the anti-leishmanial activity and cytotoxicity of aqueous and organic extracts of ten plants used in Mexican traditional medicine as anti-parasitics.

Materials and methods

For the organic extracts, plant material was macerated in dichloromethane (CH₂Cl₂) and dichloromethane/methanol (CH₂Cl₂/MeOH) (1:1) during two weeks; the aqueous extracts were prepared by infusion. The extracts were tested against promastigotes and intracellular amastigotes of Leishmania amazonensis. The cytotoxicity was assayed in parallel on peritoneal macrophages of BALB/c mice.

Results

Four of the thirty extracts tested were active and selective against L. amazonensis promastigotes: Schinus molle (CH₂Cl₂ and CH₂Cl₂/MeOH), Lantana camara (CH₂Cl₂) and Prosopis laevigata (aqueous). These extracts had a median inhibitory concentration (IC₅₀) against intracellular amastigotes under 50 μg/mL and a selectivity index (SI) higher than 5, which indicates that they constitute valuable candidates to obtain secondary metabolites with leishmanicidal activity.

Conclusions

The results derived from this study indicate that L. camara, P. laevigata, and S. molle might provide interesting new leads for the development of antileishmanial drugs.

Systematic review on traditional medicinal plants used for the treatment of malaria in Ethiopia: trends and perspectives

BACKGROUND

Ethiopia is endowed with abundant medicinal plant resources and traditional medicinal practices. However, available research evidence on indigenous anti-malarial plants is highly fragmented in the country. The present systematic review attempted to explore, synthesize and compile ethno-medicinal research evidence on anti-malarial medicinal plants in Ethiopia.

METHODS

A systematic web search analysis and review was conducted on research literature pertaining to medicinal plants used for traditional malaria treatment in Ethiopia. Data were collected from a total of 82 Ethiopian studies meeting specific inclusion criteria including published research articles and unpublished thesis reports. SPSS Version 16 was used to summarize relevant ethno-botanical/medicinal information using descriptive statistics, frequency, percentage, tables, and bar graphs.

RESULTS

A total of 200 different plant species (from 71 families) used for traditional malaria treatment were identified in different parts of Ethiopia. Distribution and usage pattern of anti-malarial plants showed substantial variability across different geographic settings. A higher diversity of anti-malarial plants was reported from western and southwestern parts of the country. Analysis of ethno-medicinal recipes indicated that mainly fresh leaves were used for preparation of remedies. Decoction, concoction and eating/chewing were found to be the most frequently employed herbal remedy preparation methods. Notably, anti-malarial herbal remedies were administered by oral route. Information on potential side effects of anti-malarial herbal preparations was patchy. However, some anti-malarial plants were reported to have potentially serious side effects using different local antidotes and some specific contra-indications.

CONCLUSION

The study highlighted a rich diversity of indigenous anti-malarial medicinal plants with equally divergent herbal remedy preparation and use pattern in Ethiopia. Baseline information gaps were observed in key geographic settings. Likewise, herbal remedy toxicity risks and countermeasures generally entailed more exhaustive investigation. Experimental research and advanced chemical analysis are also required to validate the therapeutic potential of anti-malarial compounds from promising plant species.

Treating leishmaniasis in Amazonia: A review of ethnomedicinal concepts and pharmaco-chemical analysis of traditional treatments to inspire modern phytotherapies

ETHNOPHARMACOLOGICAL RELEVANCE

Cutaneous and mucocutaneous leishmaniasis are neglected tropical diseases that occur in all intertropical regions of the world. Amazonian populations have developed an abundant knowledge of the disease and its remedies. Therefore, we undertook to review traditional antileishmanial plants in Amazonia and have developed new tools to analyze this somewhat dispersed information.

MATERIAL AND METHODS

A literature review of traditional remedies for cutaneous/mucocutaneous leishmaniasis in the Amazon was conducted and the data obtained was used to calculate distribution indexes designed to highlight the most relevant uses in Amazonia. The cultural distribution index represents the distribution rate of a given taxon among different cultural groups and was calculated as the ratio of the number of groups using the taxon to the total number of groups cited. The geographical distribution index allowed us to quantify spatial distribution of a taxon's uses in Amazonia and was calculated geometrically by measuring the average distance between the points where uses have been reported and the barycenter of those points. The general distribution index was defined as an arithmetic combination of the previous two and provides information on both cultural and spatial criteria.

RESULTS

475 use reports, concerning 291 botanical species belonging to 83 families have been gathered depicted from 29 sources. Uses concern 34 cultural groups. While the use of some taxa appears to be Pan-Amazonian, some others are clearly restricted to small geographical regions. Particular attention has been paid to the recipes and beliefs surrounding treatments. Topical application of the remedies dominated the other means of administration and this deserves particular attention as the main treatments against Neotropical leishmaniasis are painful systemic injections. The data set was analyzed using the previously defined distribution indexes and the most relevant taxa were further discussed from a phytochemical and pharmacological point of view.

CONCLUSIONS

The Amazonian biodiversity and cultural heritage host a fantastic amount of data whose systematic investigation should allow a better large-scale understanding of the dynamics of traditional therapies and the consequent discovery of therapeutic solutions for neglected diseases. Distribution indices are indeed powerful tools for emphasizing the most relevant treatments against a given disease and should be very useful in the meta-analysis of other regional pharmacopeia. This focus on renowned remedies that have not yet benefitted from extended laboratory studies, could stimulate future research on new treatments of natural origin for leishmaniasis.

In vitro antiprotozoal activity and cytotoxicity of extracts and isolated constituents from Greenwayodendron suaveolens

ETHNOPHARMACOLOGICAL RELEVANCE

The Nkundo people (Nkundo area of Bolongo, Mai-Ndombe district, Bandundu Province, DR Congo) use various plant parts of the tree Greenwayodendron suaveolens (Engl. & Diels) Verdc. (syn. Polyalthia suaveolens Engl. & Diels) (Annonaceae) against malaria, but its antiprotozoal constituents are not known.

MATERIALS AND METHODS

The crude 80% ethanol extract from the fruits, leaves, root bark and stem bark and 16 fractions were assessed in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, T. cruzi, Leishmania infantum and the chloroquine and pyrimethamine-resistant K1 strain of Plasmodium falciparum (Pf-K1). Their cytotoxic effects were evaluated against MRC-5 cells. Active constituents were isolated by chromatographic means, identified using spectroscopic methods, and evaluated in the same assays.

RESULTS

The root bark extract showed the highest activity against P. falciparum K1 (IC₅₀ 0.26µg/mL) along with the stem bark alkaloid fraction (IC₅₀ 0.27µg/mL). The root bark alkaloid fraction had a pronounced activity against all selected protozoa with IC₅₀ values <1µg/mL. The 90% methanol fractions of the different plant parts showed a pronounced activity against P. falciparum K1, with IC₅₀ values ranging between 0.36µg/mL and 0.69µg/mL. Four constituents were isolated: the triterpenes polycarpol, and dihydropolycarpol, the latter one being reported for the first time from nature, and the alkaloids polyalthenol and N-acetyl-polyveoline. They were active to a various degree against one or more protozoa, mostly accompanied by cytotoxicity. The highest selectivity was observed for N-acetyl-polyveoline against P. falciparum K1 (IC50 2.8µM, selectivity index 10.9).

CONCLUSIONS

These results may explain at least in part the traditional use of this plant species against parasitic diseases such as malaria in DR Congo.

Cytotoxicity of methanol extracts of Annona muricata, Passiflora edulis and nine other Cameroonian medicinal plants towards multi-factorial drug-resistant cancer cell lines

BACKGROUND

Cancer cells rapidly acquire resistance leading to treatment failures. In the present study, we have evaluated the cytotoxicity of 17 methanol extracts from 11 Cameroonian medicinal plants against the sensitive leukemia CCRF-CEM cells and the best ones were further tested on a panel of 8 other human cancer cell lines, including various MDR phenotypes as well as against the normal AML12 hepatocytes.

METHODS

The cytotoxicity of the extracts was determined using a resazurin reduction assay meanwhile flow cytometry was used to measure cell cycle, apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species.

RESULTS

In an initial screening using leukemia CCRF-CEM cells, ten extracts from five plants namely Alchornea floribunda, Annona muricata, Euphorbia prostata, Pachypodanthium staudtii and Passiflora edulis displayed IC50 values below 20 µg/mL. They were further tested in 8 other cell lines as well as in normal AML12 hepatocytes. All selected extracts were active against leukemia CEM/ADR5000 cells with IC50 value below 40 µg/mL. IC50 values ranging from 10.13 µg/mL (towards CEM/ADR5000 cells) to 72.01 µg/mL [towards resistant colon carcinoma HCT116 (p53-/-) cells] for Pachypodanthium staudtii roots and from 0.11 µg/mL (towards CCRF-CEM cells) to 108 µg/mL (towards P-glycoprotein-over-expressing CEM/ADR5000 cells) for doxorubicin were obtained in the eight other cancer cell lines studied. Extracts from Annona muricata leaves (AML) and seeds (AMS), and Passiflora edulis fruit (PEF) had IC50 values below 1 µg/mL against CCRF-CEM cells and below 10 µg/mL against its MDR subline CEM/ADR5000 cells. AML, AMS and PEF induced MMP-loss-mediated apoptosis in CCRF-CEM cells.

CONCLUSIONS

Results of the present study suggest that some of the tested plants namely Alchornea floribunda, Annona muricata, Euphorbia prostata, Pachypodanthium staudtii and Passiflora edulis represent a source of anticancer drugs. Annona muricata and Passiflora edulis are good cytotoxic plants that could be exploited to develop phytomedicine to fight mostly hematological cancers including MDR phenotypes.

Ethnobotanical survey of medicinal plants used as anthelmintic remedies in Gabon

ETHNOPHARMACOLOGICAL RELEVANCE

In this article, we report on an ethnobotanical survey realized at the Peyrie market in Libreville on Gabonese medicinal plants used to treat helminthiasis. While several alerts about cases of resistance to conventional anthelmintic treatments are causing to fear a public and animal health issue, the search for new sources of active compounds becomes an urgent issue. In Gabon like in many developing countries, people regularly turn to traditional medicine in case of physical ailments and/or spiritual healing therapies.

MATERIALS AND METHODS

To determine which medicinal plants are traditionally used by the populations of Libreville to fight against nematodes, medicinal plant traders were interviewed with standardized questionnaires. The surveys were conducted in the main market of Libreville. Ethnobotanical data such as frequency and percentage of families, species, administrations pathways, modes of preparations and parts of plants used were analyzed and summarized.

RESULTS

Thirty-four (34) traders were interviewed belonging to five (5) different ethnic groups. Twenty-four 24 plants used to treat intestinal, cutaneous and ocular helminthiasis were listed. The healers mainly turned towards to ligneous species. The parts of the plant used are mostly leaves and trunk bark. Most of the traditional remedies are prepared directly in water and four (4) principal routes were used for administration namely, oral, rectal, ocular and dermal.

CONCLUSION

This study allowed us to list anthelmintic species which will be subjected to a series of chemical and pharmacological assays.

Phytochemistry and pharmacology of the genus Drypetes: A review

AIMS

Traditional medicinal use of species of the genus Drypetes is widespread in the tropical regions. The aim of this review is to systematically appraise the literature available to date on phytochemistry, ethnopharmacology, toxicology and bioactivity (in vitro and in vivo) of crude extracts and purified compounds.

ETHNOPHARMACOLOGICAL RELEVANCE

Plants of the genus Drypetes (Putranjivaceae) are used in the Subsaharan African and Asian traditional medicines to treat a multitude of disorders, like dysentery, gonorrhoea, malaria, rheumatism, sinusitis, tumours, as well as for the treatment of wounds, headache, urethral problems, fever in young children, typhoid and several other ailments. Some Drypetes species are used to protect food against pests, as an aphrodisiac, a stimulant/depressant, a rodenticide and a fish poison, against insect bites, to induce conception and for general healing. This review deals with updated information on the ethnobotany, phytochemistry, and biological activities of ethnomedicinally important Drypetes species, in order to provide an input for the future research opportunities.

METHODS

An extensive review of the literature available in various recognized databases e.g., Google Scholar, PubMed, Science Direct, SciFinder, Web of Science, www.theplantlist.org and www.gbif.org, as well as the Herbier National du Cameroun (Yaoundé) and Botanic Gardens of Limbe databases on the uses and bioactivity of various species of the Drypetes was undertaken.

RESULTS

The literature provided information on ethnopharmacological uses of the Subsaharan African and Asian species of the genus Drypetes, e.g., Drypetes aubrévillii, D. capillipes, D. chevalieri, D. gerrardii, D. gossweileri, D. ivorensis, D. klainei, D. natalensis, D. pellegrini (all endemic to Africa) and D. roxburghii (Asian species), for the treatment of multiple disorders. From a total of 19 species, more than 140 compounds including diterpenes, sesquiterpenes, triterpenes (friedelane, oleanane, lupane and hopane-type), flavonoids, lignans, phenylpropanoids and steroids, as well as some thiocyanates, were isolated. Several crude extracts of these plants, and isolated compounds displayed significant analgesic, anthelmintic, antidiabetic, anti-emetic anti-inflammatory, antioxidant, antiparasitic, central nervous system depressant, cytotoxic, and insecticidal activities both in vitro and in vivo. Some toxicities associated with the stem, bark, seed and leaf extracts of D. roxburghii, and the flavonoid, amentoflavone, isolated from the stem extract of D. littoralis as well as D. gerrardii, were confirmed in the animal models and in the rat skeletal myoblast cells assays. As a consequence, traditional medicine from this genus should in future be applied with care.

CONCLUSIONS

Plants of this genus have offered bioactive samples, both from crude extracts and pure compounds, partly validating their effectivity in traditional medicine. However, most of the available scientific literatures lacks information on relevant doses, duration of the treatment, storage conditions and positive controls for examining bioefficacy of extract and its active compounds. Additional toxicological studies on the species used in local pharmacopeia are urgently needed to guarantee safe application due to high toxicity of some crude extracts. Interestingly, this review also reports 10 pimarane dinorditerpenoids structures with the aromatic ring C, isolated from the species collected in Asia Drypetes littoralis (Taiwan), D. perreticulata (China), and in Africa D. gerrardii (Kenya), D. gossweileri (Cameroon). These compounds might turn out to be good candidates for chemotaxonomic markers of the genus.

In vitro evaluation of traditionally used Surinamese medicinal plants for their potential anti-leishmanial efficacy

ETHNOPHARMACOLOGICAL RELEVANCE

Plant-based preparations are extensively used in Surinamese folk medicine for treating leishmaniasis, but often without a scientific rationale.

AIM OF THE STUDY

To evaluate 25 Surinamese medicinal plants for their potential efficacy against leishmaniasis.

MATERIALS AND METHODS

Concentrated plant extracts were evaluated for their effect on the viability of L. (V.) guyanensis AMC, L. (L.) major NADIM5, and L. (L.) donovani GEDII promastigotes, as well as intracellular amastigotes of L. (L.) donovani BHU814 in infected THP-1 cells. Selectivity was assessed by cytotoxicity against THP-1 cells.

RESULTS

The only plant extract that showed potentially meaningful anti-leishmanial activity was that from Solanum lycocarpum that displayed mean IC50 values of about 51, 61, and <16 µg/mL against L. (V) guyanensis, L. (L) major, and L. (L) donovani promastigotes, respectively; about 374 µg/mL against L. (L) donovani amastigotes; and >500 µg/mL against THP-1 cells. The Bryophyllum pinnatum, Inga alba, and Quassia amara extracts displayed moderate to high IC50 values against promastigotes (about 51 to >500 µg/mL) and/or amastigotes (about 224 to >500 µg/mL) but were relatively toxic to THP-1 cells (IC50 values <16 to about 42 µg/mL). The remaining plant extracts exhibited in many cases IC50 values close to, around, or above 500µg/mL against promastigotes, amastigotes, and THP-1 cells.

CONCLUSIONS

The S. lycocarpum preparation may be useful against leishmaniasis and may have a good safety index, warranting further investigations into its active constituents and mechanism(s) of action.

Antibacterial effects of Alchornea cordifolia (Schumach. and Thonn.) Müll. Arg extracts and compounds on gastrointestinal, skin, respiratory and urinary tract pathogens

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves, stems and roots of Alchornea cordifolia (Schumach. and Thonn.) Müll. Arg. are used as traditional medicine in many African countries for the management of gastrointestinal, respiratory and urinary tract infections as well as for the treatment of wounds.

AIM OF THE STUDY

To determine the in vitro antibacterial activity of the crude extracts of leaves and stems of A. cordifolia on gastrointestinal, skin, respiratory and urinary tract pathogens and to identify the compounds in the extracts that may be responsible for this activity.

MATERIALS AND METHODS

The antibacterial activities of crude extracts [hexane, chloroform (CHCl3), ethyl acetate (EtOAc), ethanol (EtOH), methanol (MeOH) and water (H2O)] as well as pure compounds isolated from these extracts were evaluated by means of the micro-dilution assay against four Gram-positive bacteria, i.e. Bacillus cereus ATCC 11778, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923 and S. saprophyticus ATCC 15305, as well as four Gram-negative bacterial strains, i.e. Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 13883, Moraxella catarrhalis ATCC 23246 and Proteus mirabilis ATCC 43071. The isolation of the active constituents was undertaken by bio-autographic assays in conjunction with chromatographic techniques. The identification and characterisation of the isolated compounds were done using mass spectrometry (MS) and Fourier transformed infrared spectrometry (FTIR) as well as 1D- and 2D- nuclear magnetic resonance (NMR) analyses.

RESULTS

The leaves and stems of A. cordifolia exhibited varied antibacterial activity against all eight pathogens. Most of the MIC values ranged between 63 and 2000µg/ml. The highest activities for the crude extracts (63µg/ml) were observed against S. saprophyticus [stem (EtOAc, CHCl3 and hexane), leaves (MeOH, EtOH, EtOAc and CHCl3)], E. coli [stem (MeOH and EtOH), leaves (MeOH, EtOH, EtOAc and CHCl3)], M. catarrhalis [leaves (EtOAc and CHCl3)], K. pneumoniae [stem (CHCl3), leaves (CHCl3)] and S. aureus [leaves (CHCl3)]. Seven constituents [stigmasterol (1), stigmasta-4,22-dien-3-one (2), friedelin (3), friedelane-3-one-28-al (4), 3-O-acetyl-aleuritolic acid (5), 3-O-acetyl-erythrodiol (6) and methyl-3,4,5-trihydroxybenzoate (methyl gallate) (7)] were isolated from the stem MeOH extract. All these compounds displayed some antibacterial activity against the eight pathogens with highest activity against S. saprophyticus (2µg/ml). Furthermore, this is the first report of compounds 1, 2, 3, 4, 6 and 7 isolated from A. cordifolia and where a complete set of 2D-NMR data for fridelane-3-one-28-al (4) is presented.

CONCLUSION

The study demonstrated that the antibacterial activities of A. cordifolia extracts may be due to the presence of the seven isolated compounds, where compounds 3-6 showed the best activity. The observed activity against gastrointestinal, skin, respiratory and urinary tract pathogens supports the traditional use for the treatment of such ailments.

Annickia affinis and A. chlorantha (Enantia chlorantha)--A review of two closely related medicinal plants from tropical Africa

ETHNOPHARMACOLOGICAL RELEVANCE

Annickia affinis (Exell) Versteegh & Sosef, closely related to A. chlorantha Setten & P.J.Maas (both species also referred to as Enantia chlorantha Oliv.), from the Annonaceae family, are multi-purpose medicinal plants used widely across tropical Africa. The two Annickia species are morphologically distinct from each other and have different distribution patterns, but are frequently confused. Furthermore, the name Enantia chlorantha is an illegitimate name, but is still used today.

MATERIALS AND METHODS

A review of the literature was undertaken and an in-depth analysis of previous research and future prospectives are considered. While a myriad of publications cite the species "Enantia chlorantha", this is not the case for A. affinis and A. chlorantha, and no reviews are available for any of the species to date. Consequently, a summary of their ethnobotany, phytochemistry and biological properties is presented here (for the period 1933 - November 2014) in order to substantiate their traditional importance as medicines for rural people in Africa.

RESULTS

To this effect, these species seem to be the preferred traditional treatments for malaria in tropical Africa, an area suffering heavily under the malaria pandemic. Their chemical composition is dominated particularly by various isoquinoline alkaloids, as well as by acetogenins and sesquiterpenes, which have been isolated from the bark and leaves. All three of these classes of compounds have been reported to exhibit noteworthy biological activity.

CONCLUSIONS

Due to their widespread use, especially of the bark, these species have already been categorized as threatened with extinction. Consequently this study further aims to identify areas where more research needs to be conducted involving these important species, and also to suggest possible means of increasing the biological activities of their extracts as a way to conserve the species.

In vitro antiprotozoal activity and cytotoxicity of extracts and fractions from the leaves, root bark and stem bark of Isolona hexaloba

ETHNOPHARMACOLOGICAL RELEVANCE

Isolona hexaloba (Pierre) Engl. and Diels (Annonaceae) is traditionally used in D.R. Congo against parasitic diseases including malaria.

MATERIALS AND METHODS

Two crude aqueous extracts, 3 crude methanol extracts and 3 crude 80% ethanol extracts from the leaves, root bark and stem bark together with 12 subfractions from the crude 80% ethanol extracts were evaluated in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, T. cruzi, Leishmania infantum and the chloroquine and pyrimethamine resistant K1 strain of Plasmodium falciparum. Their cytotoxic effects against MRC-5 cell lines were also assessed.

RESULTS

Results indicated that the most pronounced activities against T. b. brucei were recorded for the crude methanol extracts of root bark (IC50=1.97 µg/ml; SI>32.49) and leaves (IC50=2.65 µg/ml; SI>24.15). Three samples displayed good activity against T. cruzi: the 80% methanol extract of leaves (IC50=8.33 µg/ml; SI>3.92), its petroleum ether fraction (IC50=8.50 µg/ml; SI=2.52) and the crude aqueous extract of the stem bark (IC50=9.31 µg/ml; SI=3.46). The crude aqueous extract of the leaves exhibited a pronounced and selective activity against L. infantum (IC50=2.00 µg/ml; SI>32). The crude methanol extract of leaves (IC50=6.35 µg/ml; SI>10.10) and the 2 dichloromethane soluble fractions of the 80% ethanol extracts from root bark (IC50=6.96 µg/ml; SI=6.1) and stem bark (IC50=8 µg/ml; SI>8.00) showed good activity and selectivity against L. infantum. The most active samples against Plasmodium falciparum K1 were the leaves crude 80% ethanol extract (0.92 µg/ml) and its fractions: alkaline aqueous (IC50=0.27 µg/ml), 90% methanol (0.90 µg/ml) and dichloromethane (1.04 µg/ml), respectively, with promising selectivity indexes of 35<SI<237. None of all the tested crude extracts and fractions was found to be cytotoxic against MRC-5 cell lines except the petroleum ether soluble fraction from the leaves which displayed a cytotoxic effect (CC50=21.40 µg/ml).

CONCLUSION

Overall, extracts of I. hexaloba tested here, showed good results concerning parasitic infections such as Chagas' disease, leishmaniasis, malaria and/or sleeping sickness without considerable toxicity. The 80% ethanol extracts from leaves and their fractions turned out to be of special interest as they were the most useful in the treatment of malaria.

Potential antimalarials from African natural products: A reviw

Malaria remains an overwhelming infectious disease with significant health challenges in African and other endemic countries globally. Resistance to antimalarial drugs has become one of the most momentous challenges to human health, and thus has necessitated the hunt for new and effective drugs. Consequently, few decades have witnessed a surfeit of research geared to validate the effectiveness of commonly used traditionally medicines against malaria fever. The present review work focuses on documenting natural products from African whose activity has been reported in vivo or in vitro against malaria parasite. Literature was collected using electronic search of published articles (Google Scholar, PubMed, Medline, Sciencedirect, and Science domain) that report on antiplasmodial activity of natural products from differernts Africa region. A total of 652 plant taxa from 146 families, 134 isolated antimalarial compounds from 39 plants species, 2 herbal formulations and 4 insect/products were found to be reported in literature from 1996 to 2015. Plants species from family Asteraceae (11.04%), Fababceae (8.128%), Euphorbiaceae (5.52%), Rubiaceas (5.52%), and Apocyanaceae (5.214%), have received more scientific validation than others. African natural products possess remarkable healing properties as revealed in the various citations as promising antimalarial agents. Some of these natural products from Africa demonstrate high, promising or low activities against Plasmodium parasite. This study also shows that natural products from Africa have a huge amount of novel antimalarial compounds that could serve as a leads for the development of new and effective antiplasmodial drugs. However, in a view of bridging the gap in knowledge, clinical validation of these natural products are of paramount importance.