Antimalarial activity of some plants traditionally used in Meru district of Kenya

Efficacy of Albizia malacophylla (A.Rich.) Walp. (Leguminosae) methanol (80%) leaf extract and solvent fractions against Plasmodium berghei-induced malaria in mice model

ETHNOPHARMACOLOGICAL RELEVANCE

Novel drugs are needed to address the issue of malarial infection resistance; natural items can be a different source of these medications. Albizia malacophylla (A. Rich.) Walp. (Leguminosae) is listed as one of the antimalarial medicinal plants in Ethiopian folk medicine. However, there are no reports regarding the biological activity or phytochemistry of the plant.

AIM OF THE STUDY

Thus, this study aimed to evaluate the A. malacophylla crude extract and solvent fractions' in vivo antimalarial activity utilizing 4-day suppressive, preventative, and curative tests in mice infected with P. berghei.

MATERIALS AND METHODS

The parasite Plasmodium berghei, which causes rodent malaria, was used to infect healthy male Swiss Albino mice, weighing 23-28 g and aged 6-8 weeks. Solvent fractions such as methanol, water, and chloroform were given in addition to an 80% methanolic extract at 100, 200, and 400 mg/kg doses. A Conventional test such as parasitemia, survival time, body weight, temperature, and packed cell capacity were employed to ascertain factors such as the suppressive, curative, and preventive tests.

RESULTS

Every test substance dramatically reduced the number of parasites in every experiment. Crude extract (with the highest percentage suppression of 67.78%) performs better antimalarial effect than the methanol fraction, which is the most efficient solvent fraction with a percentage suppression of 55.74%. With a suppression value of 64.83% parasitemia level, the therapeutic effects of 80% methanolic crude extract were greater than its curative and preventative effects in a four-day suppressive test. The survival period (17 days) was longer with the hydroalcoholic crude extract dose of 400 mg/kg than with other doses of the materials under investigation.

CONCLUSIONS

The results of this investigation validate the antimalarial characteristics of A. malacophylla leaf extract. The crude extract prevented weight loss, a decline in temperature, and a reduction in PCV. The results demonstrate that the plant has a promising antimalarial effect against P. berghei, hence supporting the traditional use of the plant. Therefore, it could serve as a foundation for the development of new antimalarial drugs.

Potential of medicinal plants as antimalarial agents: a review of work done at Kenya Medical Research Institute

Background: Medicinal plants have traditionally been used as remedies against malaria. The present review attempted to compile data on scientific research evidence on antimalarial medicinal plants screened at Kenya Medical Research Institute (KEMRI), Center for Traditional Medicine and Drug (CTMDR) Research from January 2003 to December 2021. Methods: A systematic review was conducted using a predefined protocol based on PRISMA. Search was performed in Google Scholar and PubMed. One hundred and eight journal articles were identified 37 of which published on antimalarial/antiplasmodial work. Thirty journal articles with at least one author from KEMRI-CTMDR and accessible in full were selected for analysis. Relevant data was captured in MS Excel format and descriptive statistics, percentages and tables used to summarize the findings. Results: Assessment of individual plant species was considered as an independent study resulting in 1170 antiplasmodial/antimalarial tests done from 197 plant species. One hundred and fifty plant species were screened in vitro, one in vivo and 46 were both in vivo and in vitro. Three hundred and forty-four of tests reported good activity (IC50 < 10 μg/mL or parasite suppression rate of ≥50%), 414 moderate activity (IC50 values of 10-49 μg/mL or parasite suppression rate of 30%-49%) and 412 were reports of inactivity (IC50 ˃ 50 μg/mL or parasite suppression rate of <30%). Fuerstia africana and Ludwigia erecta were reported to have the highest activities, with IC50 < 1 μg/mL against Plasmodium falciparum D6 strain and chemosuppression in mice at an oral dose of 100 mg/kg, was reported as 61.9% and 65.3% respectively. Fifty five antimalarial/antiplasmodial active compounds isolated from eight plant species were reported with resinone (39) having the best activity (IC50 < 1 μg/mL). Conclusion: Though 344 of tests reported promising antimalarial activity, it was noted that there was limited evaluation of these plants in animal models, with only 9.0% (105/1170) studies and no clinical trials. This highlights an important research gap emphasizing the need for drug development studies that aim to progress study findings from preclinical to clinical studies. There is still need for extensive research on promising plant species aimed at developing new plant based antimalarial drugs.

Assessment of squalene variability and its enhancement in Amaranthus (Amaranthus caudatus L.) populations: With application to vaccine development

Amaranthus (Amaranthus caudatus L.) is the richest source of squalene among all plants. Squalene is used as a component of some adjuvants in vaccines for enhancement of the host immune response. Squalene content was estimated by high-performance liquid chromatography and amino acids profiling was performed using an amino acid analyzer. Squalene content, up to 7.66%, was found in the raw seeds of amaranthus, which was further enhanced to 8.13% by popping. The results revealed that amaranthus populations have wide significant variations (p < 0.05) in 1000 seed weight (0.61-1.13 g), protein content (11.50-19.80%), total phenols (4.36-7.82 μg GAE/mg sample), total flavonoid (0.70-2.32 mg QE/g dw), and squalene (3.23-7.66% in raw seeds and 3.38-8.12% in popped seeds). Genotypic variability in amino acids composition, viz. lysine (4.96-5.90%), arginine (8.48-8.80%), leucine (5.20-6.70%), valine (3.60-4.60%), phenylalanine (5.30-8.00%), methionine (3.08-4.97%), tyrosine (5.92-7.96), threonine (3.20-4.32%), and glycine (6.60-8.20%), was also observed. Wide genetic variability in amaranthus grains may be used for improved varietal development breeding programs. It can be further concluded that an increase of squalene content in amaranthus grains by heat treatment could be helpful to fulfil the demands of cosmetic and pharmaceutical industries, especially with respect to vaccine production against virus-generated pandemics.

Biologically Active Diterpenoids in the Clerodendrum Genus—A Review

One of the key areas of interest in pharmacognosy is that of the diterpenoids; many studies have been performed to identify new sources, their optimal isolation and biological properties. An important source of abietane-, pimarane-, clerodane-type diterpenoids and their derivatives are the members of the genus Clerodendrum, of the Lamiaceae. Due to their diverse chemical nature, and the type of plant material, a range of extraction techniques are needed with various temperatures, solvent types and extraction times, as well as the use of an ultrasound bath. The diterpenoids isolated from Clerodendrum demonstrate a range of cytotoxic, anti-proliferative, antibacterial, anti-parasitic and anti-inflammatory activities. This review describes the various biological activities of the diterpenoids isolated so far from species of Clerodendrum with the indication of the most active ones, as well as those from other plant sources, taking into account their structure in terms of their activity, and summarises the methods for their extraction.

The potential and outgoing trends in traditional, phytochemical, economical, and ethnopharmacological importance of family Onagraceae: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

The Onagraceae is a widely distributed family of flowering plants comprises about 17 genera and more than 650 species of herbs, shrubs, and trees. Onagraceae also common as willowherb family or evening primrose family is divided into two subfamilies; Ludwigioideae (mainly genus; Ludwigia) and Onagroideae. Family Onagraceae is characterized by its numerous traditional uses as treatment of hormonal imbalances, urinary system ailments, prostate health maintenance, and antimicrobial effects.

AIM OF THE STUDY

This review aims to introduce a holistic overview on the phytochemical composition, economical importance and ethnopharmacological value of different species of family Onagraceae.

MATERIALS AND METHODS

Literature review was performed using different data bases such as PubMed, Web of Science, Google Scholar and Reaxys searching for articles focused on phytochemical composition, bioactivity and ethnopharmacological history of Onagraceae species.

RESULTS

Different species of Onagraceae were reported to have a great variety of phytochemicals including flavonoids, tannins, phenolic acids, triterpenoids, saponins, and volatile/fixed oils. Onagraceae exhibited several health benefits and pharmacological activities including anti-inflammatory, antiarthritic and analgesic, antioxidant, cytotoxic, antidiabetic, and antimicrobial.

CONCLUSIONS

Family Onagraceae is an extremely important family with diverse phytochemical composition which enriches their pharmacological importance and hence it's commercial and economical value.

Developmental stages influence in vivo antimalarial activity of aerial part extracts of Schkuhria pinnata

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria remains a dire health challenge, particularly in sub-Saharan Africa. In Uganda, it is the most ordinary condition in hospital admission and outpatient care. The country's meager health services compel malaria patients to use herbal remedies such as Schkuhria pinnata (Lam.) Kuntze ex Thell (Asteraceae). Although in vivo studies tested the antimalarial activity of S. pinnata extracts, plant developmental stages and their effect at different doses remain unknown.

AIM OF THE STUDY

This study aims to determine the effect of the plant developmental stage on the antimalarial activity of S. pinnata in mice and to document the acute oral toxicity profile.

METHODS

Seeds of S. pinnata were grown, and aerial parts of each developmental stage were harvested. Extraction was done by maceration in 70% methanol. The antimalarial activity was evaluated using chloroquine-sensitive Plasmodium berghei on swiss albino mice, in a chemosuppressive test, at 150, 350, and 700 mg/kg, p.o. Standard drugs used were artemether-lumefantrine (0.57 + 3.43) mg/kg and chloroquine (10 mg/kg) as positive controls. Distilled water at 1 mL/100g was used as a negative control. The Lorke method was adopted to determine the acute toxicity of extracts.

RESULTS

The flowering stage extract had a maximum suppression of parasitemia at 700 mg/kg (68.83 ± 4.49%). Extract at other developmental stages also significantly suppressed the parasitemia (in the ascending order) fruiting (50.71 ± 1.87%), budding (54.92 ± 7.56%), vegetative (55.39 ± 2.01%) compared to the negative control (24.7 ± 2.7%), p < 0.05. Extracts from all developmental stages increased survival time, with the flowering stage having the highest survival time at 20.33 ± 0.88 days. All extracts had an LD₅₀ of 2157 mg/kg, implying that extracts are safe at lower doses.

CONCLUSION

Together, our findings revealed that the S. pinnata extracts at the flowering stage had superior antimalarial activity compared to other plant developmental stages. Extracts from all developmental stages have demonstrated a dose-dependent suppression of malarial parasites and increased survival time with an LD₅₀ of 2157 mg/kg. Thus, for better antimalarial activity, local communities could consider harvesting S. pinnata at the flowering stage. Further studies are needed to isolate pure compounds from S. pinnata and determine their antimalarial activity.

Potential anticancer activity of Acetone extracts of Toona cilliata, Seriphium plumosum and Schkuhria pinnata on HeLa cervical cancer cells

Background

Cervical cancer is common in women in less developed regions of the world. The plant biomolecules can be employed for synergistic activity with chemo- and radiotherapy. This combinations might result in reduced toxicity and increased efficacy of the treatment regimen.

Objectives

The anti-HeLa cells activity of the acetone extracts of S. plumosum, T. cilliata and S. pinnata was assessed using different parameters.

Methods

Secondary metabolite detection and antioxidant activity quantification were determined using the DPPH and ferric iron reducing assays. HeLa cell growth inhibition and mechanistics were assessed by employing MTT and Annexin-V flous assays.

Results

Observations revealed the presence of phenolic, flavonoids, tannins steroids and coumarins in all the plants extracts. High amount of total phenolic and flavonoid content were detected in S. plumosum and T. cilliata. S. plumosum extract had the best DPPH scavenging activity and ferric reducing powers.

Conclusion

Observable concentration dependent cell proliferation inhibition by test materials was exhibited. The leaf extracts from T. cilliata, S. plumosum and S. pinnata contain compounds of various polarities with free-radical, antioxidant and anti-cancerous activities that may play a beneficial role in treatment.

Medicinal plants as a fight against murine blood-stage malaria

OBJECTIVE

Malaria is an infectious parasitic disease affecting most of countries worldwide. Due to antimalarial drug resistance, researchers are seeking to find another safe efficient source for treatment of malaria. Since many years ago, medicinal plants were widely used for the treatment of several diseases. In general, most application is done first on experimental animals then human. In this article, medicinal plants as antimalarial agents in experimental animals were reviewed from January 2000 until November 2020.

MATERIALS AND METHODS

In this systematic review published articles were reviewed using the electronic databases NCBI, ISI Web of knowledge, ScienceDirect and Saudi digital library to check articles and theses for M.Sc/Ph.D. The name of the medicinal plant with its taxon ID and family, the used Plasmodium species, plant part used and its extract type and the country of harvest were described.

RESULTS AND CONCLUSION

The reviewed plants belonged to 83 families. Medicinal plants of families Asteraceae, Meliaceae Fabaceae and Lamiaceae are the most abundant for use in laboratory animal antimalarial studies. According to region, published articles from 33 different countries were reviewed. Most of malaria published articles are from Africa especially Nigeria and Ethiopia. Leaves were the most common plant part used for the experimental malaria research. In many regions, research using medicinal plants to eliminate parasites and as a defensive tool is popular.

A review on traditionally used South African medicinal plants, their secondary metabolites and their potential development into anticancer agents

ETHNOPHARMACOLOGICAL RELEVANCE

Approximately 70% of anticancer drugs were developed or derived from natural products or plants. Southern Africa boasts an enormous floral diversity with approximately 22,755 plant species with an estimated 3000 used as traditional medicines. In South Africa more than 27 million individuals rely on traditional medicine for healthcare. The use of South African plants for the treatment of cancer is poorly documented, however there is potential to develop anticancer agents from these plants. Limited ethnobotanical studies report the use of plants for cancer treatment in traditional medicine. Plants growing in tropical or subtropical regions, such as in South Africa, produce important secondary metabolites as a protective mechanism, which could be used to target various factors that play a key role in carcinogenesis.

AIMS

The aim was to collate information from primary ethnobotanical studies on South African plants traditionally used for the treatment of cancer. Evaluation of literature focused on traditionally used plants that have been tested for their in vitro activity against cancer cells. Secondary metabolites, previously identified within these plant species, were also included for discussion regarding their activity against cancer. The toxicity was evaluated to ascertain the therapeutic potential in further studies. Additionally, the aim was to highlight where a lack of reports were found regarding plant species with potential activity and to substantiate the need for further testing.

MATERIALS AND METHODS

A review of ethnobotanical surveys conducted in South Africa for plants used in the treatment of cancer was performed. Databases such as Science Direct, PubMed and Google Scholar, university repositories of master's dissertations and PhD theses, patents and books were used. Plant species showing significant to moderate activity were discussed regarding their toxicity. Compounds identified within these species were discussed for their activity against cancer cells and toxicity. Traditionally used plants which have not been scientifically validated for their activity against cancer were excluded.

RESULTS

Twenty plants were documented in ethnobotanical surveys as cancer treatments. Numerous scientific reports on the potential in vitro activity against cancer of these plants and the identification of secondary metabolites were found. Many of the secondary metabolites have not been tested for their activity against cancer cells or mode of action and should be considered for future studies. Lead candidates, such as the sutherlandiosides, sutherlandins, hypoxoside and pittoviridoside, were identified and should be further assessed. Toxicity studies should be included when testing plant extracts and/or secondary metabolites for their potential against cancer cells to give an indication of whether further analysis should be conducted.

CONCLUSION

There is a need to document plants used traditionally in South Africa for the treatment of cancer and to assess their safety and efficacy. Traditionally used plants have shown promising activity highlighting the importance of ethnobotanical studies and traditional knowledge. There are many opportunities to further assess these plants and secondary metabolites for their activity against cancer and their toxic effects. Pharmacokinetic studies are also not well documented within these plant extracts and should be included in studies when a lead candidate is identified.

Evaluation of Hepatoprotective Activity of the Crude Extract and Solvent Fractions of Clutia abyssinica (Euphorbiaceae) Leaf Against CCl4-Induced Hepatotoxicity in Mice

Background

Liver is a vital organ that plays a major role in the elimination of xenobiotics from the body. Diseases that affect the liver become major health problems and challenge health-care professionals as well as the pharmaceutical industry. Since the conventional treatment of liver diseases is associated with a wide range of adverse effects, botanical agents are commonly used. Among these agents, Clutia abyssinica is the most widely used herb in Ethiopian traditional medicine.

Objective

To evaluate the hepatoprotective activity of the crude 80% methanol extract and solvent fractions of Clutia abyssinica leaves in mice.

Methods

The leaves of Clutia abyssinica were extracted by cold maceration using 80% methanol as a solvent, and the solvent fractions were obtained in liquid-liquid extraction with chloroform, n-butanol and distilled water. Male mice were treated with the vehicles (distilled water or 2% Tween 80), three different doses (100, 200 and 400 mg/kg) of the crude 80% methanol extract and three solvent fractions, the standard drug (silymarin 100 mg/kg), and the hepatotoxicant carbon tetrachloride (CCl₄). Then, the levels of biomarkers of liver injury - such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) - and liver function such as total protein, albumin, and bilirubin were measured. Evaluation of the change in body weight and liver weight, histopathologic examination and in vitro antioxidant assay against CCl₄-induced hepatotoxicity were also carried out.

Results

The 80% methanol extract decreased the absolute and relative weight of the liver of mice at the doses of 200 and 400 mg/kg (p<0.01 and p<0.001, respectively). It also suppressed the plasma levels of AST, ALT and ALP (p<0.001) in the aforementioned doses. Among fractions, the n-butanol fraction showed maximum hepatoprotective activity in its dose of 200 and 400 mg/kg (p<0.001, in all cases). Likewise, the chloroform fraction (400 mg/kg) reduced to a similar extent (p<0.001 in all cases). In stark contrast, the aqueous fraction failed to affect the levels of all biomarkers of hepatocyte injury. The crude methanol extract and n-butanol fraction were able to return the normal hepatic architecture of hepatocytes and scavenge free radicals in the 1,1-diphenylpicrylhydrazyl (DPPH) assay.

Conclusion

Clutia abyssinica is endowed with hepatoprotective activity, probably mediated via its antioxidant activity. Thus, Clutia abyssinica can be taken as one candidate for the development of hepatoprotective agents because of its good safety profile.

Review: Southern African medicinal plants used as blood purifiers

ETHNOPHARMALOGICAL RELEVANCE

Blood purification practices, also referred to as blood cleansing or detoxification, is an ancient concept which is widespread amongst African traditional medicine, but for which no modern scientific basis exists. There prevails considerable ambiguity in defining what a blood purifier is.

AIM OF THE STUDY

The purpose of this review is to firstly define what a blood purifier is in the context of African traditional medicine and compare to other cultural and westernized interpretations. Thereafter, this study identifies traditionally used medicinal plants used as blood purifiers in southern Africa and correlates these species to scientific studies, which may support evidence for these "blood purifying plant species".

MATERIALS AND METHODS

Ethnobotanical books and review articles were used to identify medicinal plants used for blood purification. Databases such as Scopus, ScienceDirect, PubMed and Google Scholar were used to source scientific articles. An evaluation was made to try correlate traditional use to scientific value of the plant species.

RESULTS

One hundred and fifty nine plant species have been documented as traditional remedies for blood purification. Most of the plant species have some pharmacological activity, however, very little link to the traditional use for blood purification. There has been some justification of the link between blood purification and the use as an antimicrobial and this has been explored in many of the plant species identified as blood purifiers. Other pharmacological studies specifically pertaining to the blood require further attention.

CONCLUSION

Irrespective of the ambiguity of interpretation, medicinal plants used to "cleanse the blood", play an important holistic role in traditional medicine and this review with recommendations for further study provides some value of exploring this theme in the future.

In vivo antiplasmodial potential of aqueous seed extract of Ricinus communis

Introduction: Ricinus communis is used by the people of Niger-Delta region of Nigeria, for the treatment of various ailments, especially malaria. This study evaluated the antiplasmodial potentials of the aqueous seed extract of R. communis, using Plasmodium berghei berghei. Methods: Acute toxicity study was carried out to determine the median lethal dose (LD50) of the extract. Antiplasmodial effect of the extract was assessed in suppressive, repository/ prophylactic and curative models, using Swiss albino mice (15-29 g). Mice were infected intraperitoneally with 0.2 mL of parasitized blood. Extract doses administered were 54.77, 109.54 and 164.32 mg/kg/d of the seed extract and each dose had 6 replicates. Artesunate (5 mg/kg/d) and pyrimethamine (1.2 mg/kg/d) were used as standard drugs, while distilled water (10 mL/kg/d) served as control. Results: Acute toxicity study produced LD50 of 547.72 mg/kg. The extract demonstrated a dosedependent reduction in parasitaemia in all tests. At the end of 4-day test, suppressive effect of 20.80, 49.00, 75.00 and 88.40% were obtained for doses 54.77, 109.54 and 164.32 mg/kg/d of the seed extract and artesunate, respectively. In the repository test pyrimethamine was more potent (72.26%) than the seed extract (9.47%–51.42%). The extract also exhibited appreciable curative effect. The activity of the seed extract was significant when compared with the control (P < 0.05). Mice treated with the seed extract and drugs survived for longer duration than the control group. Conclusion: The aqueous seed extract of R. communis has antiplasmodial potential and its active principle should be elucidated and further investigated to help in the ongoing fight against malaria.

In vitro antiplasmodial, antitrypanosomal and antileishmanial activities of selected medicinal plants from Ugandan flora: Refocusing into multi-component potentials

ETHNOPHARMACOLOGICAL RELEVANCE

Seven medicinal plants from Ugandan flora, namely Entada abyssinica, Khaya anthotheca, Vernonia amygdalina, Baccharoides adoensis, Schkuhria pinnata, Entandropragma utile and Momordica foetida, were selected in this study. They are used to treat conditions and infections ranging from inflammations, pains and fevers to viruses, bacteria, protozoans and parasites. Two of the plants, V. amygdalina and M. foetida, are also used as human food or relish, while others are important in ethnoveterinary practices and in zoopharmacognosy in the wild. The aim of this study was to evaluate the in vitro antiplasmodial, antitrypanosomal and antileishmanial activities, along with cytotoxicity of the multi-component extracts of these plants.

MATERIALS AND METHODS

Different parts of the plants were prepared and serially extracted with hexane, petroleum ether, dichloromethane, ethyl acetate, methanol and double distilled water. Solvent free extracts were assayed for in vitro inhibition against four reference parasite strains, Plasmodium falciparum (K1), Trypanosoma brucei rhodesiense (STIB 900), Trypanosoma cruzi (Talahuen C2C4) and Leishmania donovani (MHOM-ET-67/L82) using standard methods. Toxicity was assessed against L6 skeletal fibroblast and mouse peritoneal macrophage (J774) cells and selectivity indices (SIs) calculated for the most active extracts.

RESULTS

The strongest activities, demonstrating median inhibitory concentration (IC₅₀) values ≤ 2 μg/ml, were observed for the dichloromethane and petroleum ether extracts of K. anthotheca, B. adoensis and S. pinnata. Overall, IC₅₀ values ranged from < 1 μg/ml to > 90 μg/ml. Out of 22 extracts demonstrating IC_50s < 20 μg/ml, seven were against T. b. rhodesiense (IC₅₀: 1.6-16.2 μg/ml), six against T. cruzi (IC₅₀: 2.1-18.57 μg/ml), none against L. donovani (IC₅₀: falling > 3.3 and >10 μg/ml), and nine against P. falciparum (IC₅₀: 0.96 μg/ml to 4.69 μg/ml). Selectivity indices (SI) calculated for the most active extracts ranged from <1.00 to 94.24. However, the B. adoensis leaf dichloromethane extract (a) was equipotent (IC₅₀ = 3.3 μg/ml) against L. donovani and L6 cells respectively, indicating non-specific selection. Trypanosome and Plasmodium parasites were comparatively more sensitive to the test extracts.

CONCLUSIONS

The benefits achieved from the seven tested plant species as traditional ethnomedicinal and ethnoveterinary therapies or in zoopharmacognosy against infections and conditions of animals in the wild are strongly supported by results of this study. The synergy of plant extracts, so achieved by concerted actions of the ligands, produces adequate perturbation of targets in the four parasite genera, resulting in the strong potencies exhibited by low IC₅₀ values. The total inhibitory effect, achieved as a sum of perturbations contributed by each participating compound in the extract, minimises toxic effects of the compounds as seen in the high SI's obtained with some extracts. Those extracts demonstrating SI ≥ 4 form promising candidates for further cell-based and system pharmacology studies.

Vangueria madagascariensis Fruit Tree: Nutritional, Phytochemical, Pharmacological, and Primary Health Care Applications as Herbal Medicine

Vangueria madagascariensis J. F. Gmel. is a plant species regarded as an important fruit tree and medicinal plant in sub-Saharan Africa. This study critically reviewed the nutritional value, phytochemistry, medicinal uses, and pharmacological properties of V. madagascariensis. Relevant information on food and medicinal uses of the species was collected from electronic databases such as ISI Web of Knowledge, ProQuest, ScienceDirect, OATD, Scopus, OpenThesis, PubMed, and Google Scholar, and preelectronic literatures were obtained from the university library covering the period 1966 to 2018. Literature studies revealed that V. madagascariensis has been integrated into farming systems as a fruit tree to support income and nutritional security of households in the region. Vangueria madagascariensis is used as a herbal medicine against diabetes, gastrointestinal problems, malaria, pain, parasitic worms, and skin diseases. Phytochemical compounds identified from the species include alcohols, aldehydes, esters, furanoids, ketones, and terpenoids. Pharmacological studies revealed that V. madagascariensis extracts have antibacterial, anticonvulsant, antidiabetic, antifungal, anti-inflammatory, antioxidant, cytotoxicity, antimalarial, and antiplasmodial properties. Vangueria madagascariensis should be subjected to detailed nutritional, pharmacological, and toxicological evaluations aimed at correlating the traditional uses of the species and the scientific evidence as well as establishing the efficacy, clinical relevance, safety, and mechanisms of action of the plant extracts and compounds.

Scientific rationale for traditional use of plants to treat tuberculosis in the eastern region of the OR Tambo district, South Africa

ETHNOPHARMACOLOGICAL RELEVANCE

Tuberculosis (TB) remains a major health problem for humans worldwide, and was responsible for 1.4 million human deaths in 2015 alone. Although there is treatment for TB, emerging multi-drug, extensively drug and totally drug resistant forms of this disease, as well as co-infection with human immunodefiency virus (HIV) continue to worsen the situation. South Africa is among countries with reported traditional use and published documentation of such knowledge concerning the use of plants against TB. Based on a previous study where plants used traditionally for treating TB in the eastern region of OR Tambo district, South Africa, were documented, the present study aimed to determine the antimycobacterial effect, cytotoxicity and genotoxicity of plants selected from that list.

MATERIAL AND METHODS

Acetone, 70% ethanol, cold and hot water extracts were tested for antimycobacterial activity against saprophytic Mycobacterium species including M. aurum, M. bovis BCG, M. gordonae, M. fortuitum, and M. smegmatis using a microdilution method. Extracts with MIC values less than 1 mg/ml against at least three Mycobacterium strains were evaluated for antimycobacterial activity against pathogenic Mycobacterium strains including M. tuberculosis H37RV, M. tuberculosis and M. bovis, cytotoxicity (against Vero monkey kidney and bovine dermis cells), and genotoxicity (against Salmonella typhimurium TA98 and TA100).

RESULTS

The MIC values of the extracts ranged from 0.02 to 2.50 mg/ml, LC₅₀ values of twenty-nine extracts ranged from 0.001 to > 1 mg/ml and the highest selectivity index was 79.50, an extremely promising value. Phymaspermum acerosum roots and leaves (ethanol and water) extracts had the best MIC value (0.02 mg/ml) against at least one Mycobacterium strain. It was interesting to note the lack of cytotoxicity of these extracts with the highest selectivity index value of 39.75. Pterocelastrus echinatus bark acetone and Protorhus longifolia leaf hot water extracts were the most cytotoxic with LC₅₀ = 0.001 and 0.008 mg/ml, respectively, whereas Pittosporum viridiflorum bark water extract was genotoxic. Among non-pathogenic strains, M. gordonae, M. aurum, M. smegmatis showed good correlation of activity with pathogenic M. tuberculosis H37Rv, M. tuberculosis and M. bovis, however, M. aurum was the best predictor with Mycobacterium tuberculosis H37Rv (correlation coefficient value = 0.73).

CONCLUSION

The results indicate that Heteromorpha trifoliata and Phymaspermum acerosum should be investigated further for antimycobacterial efficacy against drug resistant strains of Mycobacterium.

Anti-hyperalgesic activity of the aqueous and methanol extracts of the leaves of Pittosporum mannii Hook on CFA-induced persistent inflammatory pain

BACKGROUND

Previous study showed that aqueous (AEPM) and methanol (MEPM) extracts from the leaves of Pittosporum mannii have analgesic effects in acute pain models. The present study evaluates the acute and chronic anti-hypernociceptive and anti-inflammatory effects of AEPM and MEPM in a model of persistent inflammatory pain.

METHODS

The third day after induction of inflammatory pain by subplantar injection of 100 µL of CFA in Wistar rats, AEPM and MEPM were administered orally (75, 150 and 300 mg/kg/day) and their anti-hyperalgesic and anti-inflammatory effects were follow in acute (1-24 h) and chronic (for 14 days) treatments. At the end of the chronic treatment, oxidative stress and liver parameters were assessed. Effects of plant extracts were also evaluated on nociception induced by Phorbol 12-Myristate 13-Acetate (PMA) and 8-bromo 3',5'-cAMP (8-Br-cAMP) in mice.

RESULTS

AEPM and MEPM significantly reversed the mechanical hyperalgesia caused by CFA in acute and chronic treatment. Moreover, AEPM and MEPM also significantly reduced the nociception caused by PMA (60%) and 8-Br-cAMP (87%). Nevertheless, AEPM and MEPM failed to inhibit the paw edema caused by CFA. Plant extracts significantly reduced the nitric oxide content in the spinal cord and the plasmatic concentration of alanine aminotransferase. MEPM also significantly increased the glutathione content in the spinal cord.

CONCLUSION

AEPM and MEPM given orally are effective in inhibiting mechanical hyperalgesia in persistent inflammatory pain caused by CFA. Their mechanisms of action seem to involve an interaction with PKC, PKA and nitric oxide pathways. These extracts might be devoid of hepatotoxic effects.

Pittosporum viridiflorum Sims (Pittosporaceae): A review on a useful medicinal plant native to South Africa and tropical Africa

ETHNOPHARMACOLOGICAL RELEVANCE

Pittosporum viridiflorum Sims, a Pittosporaceae species, is used extensively in African traditional medicine (ATM) by various tribes. This review is an appraisal of the information concerning the description, distribution, conservation status, traditional uses, phytochemistry, pharmacology and toxicology of this species with the aim of reconciling it with its traditional use.

MATERIALS AND METHODS

A wide-ranging literature search was conducted using database platforms such as Scopus, Google Scholar, Web of Science, ScienceDirect, PubMed and books including local reports and thesis submissions.

RESULTS

Ten categories to which P. viridiflorum finds use in traditional medicine (TM) were found, and they include well-being, wounds, treatment of veterinary ailments, gastrointestinal and sexually transmitted diseases, kidney, circulatory and inflammatory disorders, as well as diseases such as cancer, tuberculosis, and malaria. Pharmacological tests conducted include those investigating antimicrobial, antidiarrhoeal, antimalarial, anticancer, anti-inflammatory, antioxidant and acaricidal properties. Promising activity was shown in a number of assays. Toxicological effects have also been reported from this species. However, it is recommended to conduct a detailed toxicological study, including genotoxicity, as this has not yet been evaluated. Compound(s) with antimalarial, anticancer and acaricidal properties have been isolated from P. viridiflorum.

CONCLUSIONS

The collective pharmacological and phytochemical properties of P. viridiflorum gives credence to the use of this plant species against various diseases in ATM, thus steering significant interest towards in vivo studies and further research.

Antinociceptive effects of the aqueous and methanol extracts of the leaves of Pittosporum mannii Hook. F. (Pittosporaceae) in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Pittosporum mannii (Pittosporaceae) is used in Africa traditional medicine to treat various ailments including pain and inflammation.

AIM OF THE STUDY

The present work was undertaken to evaluate the antinociceptive effects of the aqueous (AEPM) and methanol (MEPM) extracts from the leaves of Pittosporum mannii.

METHODS

High performance liquid chromatography coupled with mass spectrometry (LCMS) was used for the phytochemical analysis of AEPM prepared as decoction and MEPM prepared as cold maceration. The in vitro cytotoxicity of AEPM and MEPM were evaluated on Artemia salina larvae. AEPM and MEPM antinociceptive effects were evaluated at the doses of 35, 75, 150 and 300mg/kg given orally, against pain induced by acetic acid, formalin, hot plate, capsaicin and glutamate. The rota rod test was also performed at the same doses. To determine the mechanism of action of these extracts, their antinociceptive effects were tested in animals pretreated with yohimbine (α2-adrenergic antagonist), atropine (muscarinic antagonist) or naloxone (an opioids antagonist).

RESULT

The LCMS analysis showed that both extracts contain pittovidoside and 1-O-rhamnopyranosyl-23-acetoxyimberbic acid 29-methyl ester, the aqueous extract being more concentrated. Oral administration of both extracts significantly reduced pain symptoms induced by acetic acid, formalin, capsaicin, glutamate and hot plate. The antinociceptive effect of AEPM was significantly inhibited by yohimbine, atropine and naloxone while these inhibitors tend to potentiate the activity of MEPM. Both extracts have no effect on Rota rod test. AEPM and MEPM showed respective LC50 of 2.44 and 0.70mg/ml on Artemia larvae and were therefore, considered non-toxic.

CONCLUSION

These results indicate that AEPM and MEPM possesses analgesic effects with different mechanism of action. Although effects of both extracts may involve TRPV1 receptors and glutamatergic pathway, AEPM may in addition, interact with alpha-adrenergic, muscarinic and opioidergic pathways that are not involve in the effects of MEPM.

Role of traditional antimalarial plants in the battle against the global malaria burden

Malaria continues to be a major global public health problem with 3.3 billion people at risk in 106 endemic countries. Globally, over 1000 plants have been used as potential antimalarials in resource-poor settings due to fragile health-care systems and lack of accessibility and affordability of artemisinin-based combination therapies (ACTs). Although many believe that the use of medicinal plants that have folklore reputations for antimalarial properties is relatively safe, many herbs may be potentially toxic due to their intrinsic adverse side effects. Therefore, herbal-derived remedies require powerful and deep assessment of their pharmacological qualities to establish their mode of action, safety, quality, and efficacy. In addition, the evolution of drug resistance also demands new antimalarial agents. This can be achieved by forming a vibrant antimalarial discovery pipeline among all stakeholders, including traditional healers, ethnobotanists, scientists, entomologists, pharmacists, and research institutions, for the isolation and characterization of the bioactive compounds with the ultimate objective of finding novel modes of action antimalarial compounds that can be used to fight against drug-resistant malarial parasites.

In vivo antiplasmodial activities of ethanolic extract and fractions of Eleucine indica

OBJECTIVE

To evaluate the in vivo antiplasmodial activities of the extract and fractions (n-hexane, chloroform, ethylacetate, butanol, aqueous) of the whole plant in Plasmodium berghei berghei infected mice.

METHODS

Oral administrations of the extract (200, 400, and 600 mg/kg) of Eleucine indica and fractions (400 mg/kg) were screened in the 4-day, repository and curative tests. Chloroquine (5 mg/kg), pyrimethamine (1.2 mg/kg) and artesunate (5 mg/kg) were used as controls.

RESULTS

The extract showed significant (P< 0.05-0.001) dose-dependent, antiplasmodial activity in the 4-day, repository and curative tests and increased the survival times of the infected mice. All the fractions exhibited significant antiplasmodial activity with the highest being ethylacetate fraction.

CONCLUSIONS

Eleucine indica extract and fractions possess antimalarial activity which confirms the ethnobotanical use of this plant as a malarial remedy and opens a new highway to further investigate its potentials in the on-going fight against malaria.

Antioxidant activities of some cameroonian plants extracts used in the treatment of intestinal and infectious diseases

Antioxidant activity test using two different methods namely 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothialozinesulfonate) diammonium salt free radical scavenging test has been carried out on three Cameroonian plant extracts used in the treatment of intestinal and infectious diseases: Pittosporum mannii Hook f. (Pittosporaceae), Vepris heterophylla R. Letouzey (Rutaceae) and Ricinodendron heudelotii (Baill) Pierre ex Pax (Euphorbiaceae). Results of this study in the 2,2-diphenyl-1-picrylhydrazyl scavenging test show that the ethyl acetate extract of P. mannii and the methanol extract of V. heterophylla exhibit high free radical scavenging activities with IC(50) values of 177.74 and 204.69 mug/ml, respectively while the methanol/dichloromethane (1+1) extract of R. heudelotii showed weak free radical scavenging activities as compared to Trolox (939.19 mug/ml) used as standard. In the same manner, 2,2'-azinobis(3-ethylbenzothialozinesulfonate) diammonium salt radical scavenging test of these extracts was in accordance of the result of 2,2-diphenyl-1-picrylhydrazyl test. The antioxidant properties of these extracts probably explain partly, the use of these plants in traditional medicine for the treatment of infectious diseases and inflammations.

Antimicrobial and Antiparasitic Abietane Diterpenoids from the Roots of Clerodendrum eriophyllum

Chromatographic separation of the roots of a Kenyan medicinal plant, Clerodendrum eriophyllum, led to the isolation of ten abietane diterpenoids (1-10), one of which (1) was isolated for the first time from a natural source. Using spectroscopic data, the structure of 1 was determined to be 12-hydroxy-8,12-abietadiene-3,11,14-trione. Circular dichroism (CD) spectra showed that the stereochemistry of compounds 1, 3, and 6-8 belongs to the normal series of abietane diterpenes, which confirmed the absolute stereochemistry of the isolated compounds. Compounds 1-10 were evaluated for their in vitro antiplasmodial, antileishmanial, antifungal and antibacterial activities. Compounds 3 and 7 exhibited potent antifungal activity (IC50/MIC 0.58/1.25 and 0.96/2.5 μg/mL, respectively) against C. neoformans, whereas 3, 6 and 7 showed strong antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus with IC50/MIC values between 1.33-1.75/2.5-5 and 0.96-1.56/2.5 μg/mL, respectively. In addition, compounds 3 and 9 exhibited potent antileishmanial activity (IC50 0.08 and 0.20 μg/mL, respectively) against L. donovani, while 3 and 7 displayed weak antimalarial activity against Plasmodium falciparum, but 9 was inactive.

Antiplasmodial and cytotoxic activities of Rwandan medicinal plants used in the treatment of malaria

AIM OF THE STUDY

In our study, methanol, dichloromethane and aqueous extracts of 13 Rwandan medicinal plants used in the treatment of malaria were tested for in vitro antiplasmodial activity.

MATERIALS AND METHODS

The growth inhibition of chloroquine-sensitive Plasmodium falciparum strain (3D7) was evaluated using the measurement of lactate dehydrogenase activity. The active extracts were also tested against the chloroquine-resistant Plasmodium falciparum strain (W2) and for cytotoxicity assay using human normal foetal lung fibroblasts (WI-38).

RESULTS

The majority of the plants tested showed an antiplasmodial activity and the best results were observed with dichloromethane leaf and flower extracts of Tithonia diversifolia, leaf extract of Microglossa pyrifolia and root extract of Rumex abyssinicus, methanol leaf extract of Fuerstia africana, root bark extracts of Zanthoxylum chalybeum and methanol bark extract of Terminalia mollis. Those extracts were active (IC(50)<15mug/ml) on both chloroquine-sensitive and resistant strains of Plasmodium falciparum. Zanthoxylum chalybeum, Solanecio mannii and Terminalia mollis presented the best selectivity index.

CONCLUSIONS

The traditional use of most of the plant evaluated was confirmed by the antiplasmodial test. This study revealed for the first time the antiplasmodial activity of two plants: Terminalia mollis and Rumex abyssinicus.

Hypoglycaemic activity of four plant extracts traditionally used in South Africa for diabetes

AIM

To validate plant species for hypoglycaemic activity.

MATERIALS AND METHODS

Four plants were investigated for hypoglycaemic activity by evaluating inhibiting effects on carbohydrate-hydrolising enzymes: alpha-glucosidase and alpha-amylase. Acetone plant extracts were screened against C2C12 myocytes, 3T3-L1 preadipocytes and Chang liver cells by measuring glucose uptake. Cytotoxicity was done in preadipocytes and hepatocytes.

RESULTS

Extract of Euclea undulata rootbark exhibited highest activity, displaying a glucose uptake of 162.2% by Chang liver cells at 50 microg/ml. An inhibition concentration of 50% for Euclea undulata was found to be 49.95 microg/ml for alpha-glucosidase and 2.8 microg/ml for alpha-amylase. No cytotoxicity was recorded for Euclea undulata, while Schkuhria pinnata and Elaeodendron transvaalense exhibited cytotoxicity at 12.5 microg/ml. Alpha-glucosidase and alpha-amylase assays showed inhibitory activity on enzymes for three plant extracts.

CONCLUSION

Euclea undulata, Schkuhria pinnata and Elaeodendron transvaalense showed in vitro hypoglycaemic activity. Schkuhria pinnata and Elaeodendron transvaalense indicated cytotoxicity on 3T3-L1 preadipocytes and Chang liver cells. Euclea undulata, Pteronia divaricata and Elaeodendron transvaalense inhibited alpha-glucosidase and alpha-amylase enzymes.

ETHNOPHARMACOLOGICAL RELEVANCE

Screening of plant extracts scientifically validated traditional use of Euclea undulata for treatment of diabetes. Cytotoxicity results revealed that acetone extracts of Schkuhria pinnata and Elaeodendron transvaalense are toxic and raise concern for chronic use.

Anti-plasmodial activity of the extracts of some Kenyan medicinal plants

ETHNOPHARMACOLOGICAL RELEVANCE

The spread of drug resistant Plasmodium falciparum strains necessitates search for alternative newer drugs for use against malaria. Medicinal plants used traditionally in preparation of herbal medicines for malaria are potential source of new anti-malarial drugs.

AIM OF THE STUDY

To identify the anti-plasmodial potential of twelve plants used in preparing herbal remedies for malaria in Kilifi and Tharaka districts of Kenya.

MATERIALS AND METHODS

Twelve plants used traditionally for anti-malarial therapy in Kilifi and Tharaka districts were extracted with water/methanol yielding twenty-three extracts. The extracts were tested against chloroquine sensitive (NF54) and resistant (ENT30) P. falciparum strains in vitro using (3)Hypoxanthine assay.

RESULTS

Seven (30%) extracts showed activity against P. falciparum with IC(50) values below 20 microg/ml. The remaining 16 extracts showed low or no activity. The most active extracts were from Zanthoxylum chalybeum (Rutaceae) with an IC(50) value of 3.65 microg/ml, Cyperus articulatus (Cyperaceae) with 4.84mug/ml, and Cissampelos pareira (Menispermaceae) with 5.85 microg/ml.

CONCLUSIONS

This study revealed plants, that are potential sources of anti-malarial compounds. Anti-plasmodial activities of extracts of T. simplicifolia, C. pareira, and C. articulatus are reported for the first time.