In vivo trypanocidal activity of Annona senegalensis Pers. leaf extract against Trypanosoma brucei brucei

The relative role of soil, climate, and genotype in the variation of nutritional value of Annona senegalensis fruits and leaves

Annona senegalensis Pers is a multipurpose tree species valued for food and medicinal uses in Africa. Although there have been attempts to document the proximate composition of fruits and leaves, little is known about the relative role of soil, climate, and genotype on the nutritional quality. The present study evaluated the variation of the proximate composition of fruits and leaves in populations from Benin and Mozambique. It further assessed the impact of soil, climate and genotype on the proximate composition. Data were collected from four populations genetically different and analyzed using descriptive statistics, analysis of variance (ANOVA), principal component analysis, redundancy analysis (RDA), and variance partitioning. Results revealed significant variation in the proximate composition of fruits and leaves among the studied populations. Ashes and fibers in fruits, and lipids in leaves were 4.8-fold, 2.5- fold, and 1.25-fold higher respectively, in populations from Mozambique. Fruits moisture and lipids content were rather 1.4-fold and 1.10-fold higher in populations from Benin. Moisture and lipids were respectively 6-fold and 1.27-fold higher in fruits than in leaves, while ashes, fibers and proteins were approximately twice higher in the leaves than in the fruits. Genetic groups, climate and soils were found to influence this variation. All three factors explained 74.4% of the variation of nutritional value of fruits and leaves, 31.9% of which was exclusively due to genetic variation, 2.8% to the interaction of climate and soils, 24.1% to the interaction of soil and genetic variation, and 15.5% to the interaction of all three factors. Our study shows that genetic variation and soil properties better than climate, explain the variation of nutritional value of A. senegalensis fruits and leaves and further provides essential information that could be harnessed in the domestication and breeding program of the species for its edible parts.

In vitro and in vivo antitrypanosomal efficacy of combination therapy of Anogeissus leiocarpus, Khaya senegalensis and potash

ETHNOPHARMACOLOGICAL RELEVANCE

Pastoralists in Nigeria mix barks of Anogeissus leiocarpus (AL) Khaya senegalensis (KS) and potash (Pt) to treat animal African trypanosomosis.

AIM

To evaluate antitrypanosomal potential of A. leiocarpus, K. senegalensis and potash for insights into the traditional claim of antitrypanosomal combination therapy (ATCT).

MATERIALS AND METHODS

Fifty microliter each of six different concentrations of AL, KS, Pt, AL + KS, AL + KS + Pt and diminazene aceturate (DA, positive control) was incubated with 50 μL of parasite-laden blood containing 10⁸Trypanosoma congolense cells in a 96-well microtitre plate. Negative control wells were devoid of the extracts and drug but supplemented with phosphate-buffered saline (PBS). Efficacy of treatment was observed at 1 h interval for complete immobilisation or reduced motility of the parasites. Each incubated mixture was inoculated into mouse at the point of complete immobilisation of parasite motility or at the end of 6-h observation period for concentrations that did not immobilise the parasites completely. For in vivo assessment, thirty-five parasitaemic rats were randomly allocated into seven groups of 5 rats each. Each rat in groups I-V was treated with 500 mg/kg of AL, KS, Pt, AL + KS and AL + KS + Pt, respectively, for 7 days. Rats in groups VI and VII were treated with diminazene aceturate 3.5 mg/kg once and PBS 2 mL/kg (7 days), which served as positive and negative controls, respectively. Daily monitoring of parasitaemia through the tail vein, packed cell volume and malondialdehyde were used to assess efficacy of the treatments.

RESULTS

The AL + KS + Pt group significantly (p < 0.05) and dose-dependently reduced parasite motility and completely immobilized the parasites at 10, 5 and 2.5 μg/μL with an IC₅₀ of 9.1×10^-4 µg/µL. All the mice with conditions that produced complete cessation of parasite motility did not develop parasitaemia within one month of observation. The AL + KS group significantly (p < 0.05) lowered the level of parasitaemia and MDA, and significantly (p < 0.05) maintained higher PCV than PBS group.

CONCLUSION

The combination of A. leiocarpus and K. senegalensis showed better antitrypanosomal effects than single drug treatment and offers prospects for ATCT. Our findings support ethnopharmacological use of combined barks of A. leiocarpus and K. senegalensis by pastoralist in the treatment of animal African trypanosomosis in Nigeria.

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.

Alterations of Antioxidant Status and Mitochondrial Succinate Dehydrogenase Activity in the Liver of Wistar Strain Albino Rats Treated with by Ethanol Extracts of Annona senegalensis Pers (Annonaceae) Stem Bark

Numerous ethnomedicinal uses have been attributed to different parts of Annona senegalensis (ASE), including its uses as food and food additives. The present study investigated toxicological and antioxidant effects of 28 days administration of ethanol extracts of ASE stem bark to Wistar strain albino rats. Acute toxicity test was done to determine lethal dose in Wistar rats while sub-acute toxicity test was conducted on rats divided into four groups (A - control, B - 50 mg/kg, C - 100 mg/kg, D - 150 mg/kg, respectively and treated for 28 days. Oxidative stress markers in liver and kidney as well as hepatic succinate dehydrogenase activity in the mitochondrial and post mitochondrial fractions (PMF) were evaluated. The LD₅₀ value of ASE was > 2,000 mg/kg. White blood cell counts gradually increased, but red blood cell counts and haematocrits level decreased significantly (p < 0.05) by about 50%. Liver enzymes in the serum and mitochondrial succinate dehydrogenase activity increased significantly (p < 0.05). Superoxide dismutase and catalase activities also increased in liver mitochondria and PMF while malondialdehyde (MDA) and reduced glutathione levels increased only in the PMF. Furthermore, only MDA levels increased significantly in the kidney after 28 days extract administration. Histopathological examination showed hepatic necrosis and no obvious signs of nephrotoxicity. Anona senegalensis is relatively safe, but prolonged ingestion could induce oxidative stress and impair ATP synthesis through the modulation of the activity of mitochondrial succinate dehydrogenase.

Potential therapeutic applications of the genus Annona: Local and traditional uses and pharmacology

ETHNO-PHARMACOLOGICAL RELEVANCE

Annona species (Annonaceae) have long been used as traditional herbal medicines by native peoples in tropical areas. In different countries they are used against a large variety of illnesses, such as parasitic and infectious diseases, cancer, diabetes, peptic ulcers, and mental disorders.

AIM OF THE STUDY

This review aims to achieve a comprehensive understanding of the research conducted so far on the local and traditional uses, pharmacological activities, mechanism of actions of active compounds, toxicity, and possible interactions with other drugs of the Annona species. Through analysis of these findings, evidences supporting their applications in ethno-medicines are described. We discuss the possible research opportunities and stand out the weak points in our knowledge that deserves further investigation.

MATERIAL AND METHODS

Information on ethno-medicinal uses and pharmacological activities of the Annona genus was collected. The main scientific biomedical literature databases (Cochrane, PubMed, Scopus, Lilacs, SeCiMed, Elsevier, SpringerLink, Google Scholar, SciFinder) were consulted. The search covered all the literature available until September 2017. National and regional databases of Herbal Medicine and Complementary and Alternative Medicine were also revised in order to explore further data. For a better understanding of the therapeutic importance of these species, we have classified the pharmacological activities within each group of disorders. The International Classification of Diseases (ICD), used from WHO Member States, was chosen as the reference classification.

RESULTS

From among the 27 species revised, four species are highlighted for their important pharmacological activities in most of the groups of illnesses: A. muricata, A. squamosa, A. senegalensis, and A. cherimola. Many investigations have been performed with extracts from the leaves, bark, fruit and seeds and have shown a wide range of pharmacological activities, such as antiprotozoal, antitumoural, antidiabetic, hepato-protective, anti-inflammatory and anxiolytic activities. The chemistry on the annonaceous acetogenins (ACGs) has been extensively investigated due to their potent antitumoural activity. Many of the assays were carried out with the isolated acetogenins in different lines of tumour culture cells and were found effective at very low doses even in multidrug-resistant tumours, and hence constitute promising compounds in the treatment of different types of cancers. No studies were found with extracts rich in acetogenins in the clinical field.

CONCLUSIONS

The experimental results from the pharmacological research enable the validation of their traditional uses in several of the groups of diseases in the countries of origin and reveal these plants to be a valuable source for therapeutic molecules. However, more toxicity assays and clinical trials would be necessary to establish optimal and safe doses of consumption on the application of these medicinal plants.

Design and Synthesis of Broad Spectrum Trypanosomatid Selective Inhibitors

Neglected tropical diseases caused by parasitic infections are an ongoing and increasing concern that have a devastating effect on the developing world due to their burden on human and animal health. In this work, we detail the preparation of a focused library of substituted-tetrahydropyran derivatives and their evaluation as selective chemical tools for trypanosomatid inhibition and the follow-on development of photoaffinity probes capable of labeling target protein(s) in vitro. Several of these functionalized compounds maintain low micromolar activity against Trypanosoma brucei, Trypanosoma cruzi, Leishmania major, and Leishmania donovani. In addition, we demonstrate the utility of the photoaffinity probes for target identification through preliminary cellular localization studies.

Animal African Trypanosomiasis in Nigeria: A long way from elimination/eradication

Animal African Trypanosomiasis (AAT) is a disease of livestock that directly hinders livestock production and therefore impedes the socio-economic development of sub-Saharan Africa. The establishment of the Pan-African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC) was to enhance the goal of elimination and eradication of tsetse flies and AAT from endemic countries in Africa. In order to achieve AAT eradication, a five-step progressive control pathway (PCP) model has been proposed. The data presented in this report demonstrates that Nigeria is highly endemic of AAT and that it is yet to comprehensively approach the process of eradication as it is at the infancy stage of data gathering and processing. This review is thus presented to serve as a wake-up call to all relevant stakeholders to intensify efforts in approaching the painstaking process of AAT eradication in Nigeria.

Simplifying nature: Towards the design of broad spectrum kinetoplastid inhibitors, inspired by acetogenins

The need for new treatments for the neglected tropical diseases African sleeping sickness, Chagas disease and Leishmaniasis remains urgent with the diseases widespread in tropical regions, affecting the world's very poorest. We have previously reported bis-tetrahydropyran 1,4-triazole analogues designed as mimics of the annonaceous acetogenin natural product chamuvarinin, which maintained trypanocidal activity. Building upon these studies, we here report related triazole compounds with pendant heterocycles, mimicking the original butenolide of the natural product. Analogues were active against T. brucei, with a nitrofuran compound displaying nanomolar trypanocidal activity. Several analogues also showed strong activity against T. cruzi and L. major. Importantly, select compounds gave excellent selectivity over mammalian cells with a furan-based analogue highly selective while remaining active against all three cell lines, thus representing a potential lead for a new broad spectrum kinetoplastid inhibitor.

Ethnomedical and ethnobotanical investigations on the response capacities of Guinean traditional health practioners in the management of outbreaks of infectious diseases: The case of the Ebola virus epidemic

ETHNOPHARMACOLOGICAL RELEVANCE

The recent outbreak of Ebola virus infections has mostly remained confined to the West African countries Guinea-Conakry, Sierra-Leone and Liberia. Due to intense national and international mobilizations, a significant reduction in Ebola virus transmission has been recorded. While international efforts focus on new vaccines, medicines and diagnostics, no coherent national or international approach exists to integrate the potential of the traditional health practitioners (THPs) in the management of infectious diseases epidemics. Nevertheless, the first contact of most of the Ebola infected patients is with the THPs since the symptoms are similar to those of common traditionally treated diseases or symptoms such as malaria, hemorrhagic syndrome, typhoid or other gastrointestinal diseases, fever and vomiting.

MATERIALS AND METHODS

In an ethnomedical survey conducted in the 4 main Guinean regions contacts were established with a total of 113 THPs. The socio-demographic characteristics, the professional status and the traditional perception of Ebola Virus Disease (EVD) were recorded.

RESULTS

The traditional treatment of the main symptoms was based on 47 vegetal recipes which were focused on the treatment of diarrhea (22 recipes), fever (22 recipes), vomiting (2 recipes), external antiseptic (2 recipes), hemorrhagic syndrome (2 recipes), convulsion and dysentery (one recipe each). An ethnobotanical survey led to the collection of 54 plant species from which 44 identified belonging to 26 families. The most represented families were Euphorbiaceae, Caesalpiniaceae and Rubiaceae. Literature data on the twelve most cited plant species tends to corroborate their traditional use and to highlight their pharmacological potential.

CONCLUSIONS

It is worth to document all available knowledge on the traditional management of EVD-like symptoms in order to evaluate systematically the anti-Ebola potential of Guinean plant species.

Anti-trypanosomal activity of nigerian plants and their constituents

African trypanosomiasis is a vector-borne parasitic disease causing serious risks to the lives of about 60 million people and 48 million cattle globally. Nigerian medicinal plants are known to contain a large variety of chemical structures and some of the plant extracts have been screened for antitrypanosomal activity, in the search for potential new drugs against the illness. We surveyed the literatures on plants and plant-derived products with antitrypanosomal activity from Nigerian flora published from 1990 to 2014. About 90 plants were identified, with 54 compounds as potential active agents and presented by plant families in alphabetical order. This review indicates that the Nigerian flora may be suitable as a starting point in searching for new and more efficient trypanocidal molecules.

Medicinal plants and traditional healing practices in Ehotile people, around the Aby Lagoon (eastern littoral of Côte d'Ivoire)

BACKGROUND

Access to useful plants is a growing problem in Africa, increased by the loss of natural vegetation and the erosion of traditional knowledge. Ethnobotany contributes to promote these indigenous knowledge. Despite the large diversity of ethnic groups in Côte d'Ivoire, few ethnomedicine researches have targeted these groups. Among the great Akan group, the Ehotile people are one of the smallest and oldest ethnic group around the Aby Lagoon. The goal of this study was to analyze the level of knowledge and use of medicinal plants by the Ehotile people, and moreover, contribute to build a database about useful plants of first Ivorian people.

METHODS

Two sets of surveys were conducted in four Ehotile villages: a house-to-house freelist interview and an individual walk-in-the woods interview with some key informants identified by the community. Frequency of citation, Smith's index, Use value and Informant Consensus Factor were used to estimate the local knowledge of medicinal plants.

RESULTS

Medicinal plants are widely used by Ehotile people. Some were used in addition to modern prescriptions while for some disorders commonly called "African diseases" only plants are used. 123 species employed in the treatment of 57 diseases were listed. Specifically, the most common indications included malaria, sexual asthenia, troubles linked to pregnancy, dysmenorrhoea and haemorrhoids. Analysis of freelists suggested that Ehotile people has a good knowledge of medicinal plants and the most salient included Harungana madagascariensis, Alstonia boonei, Ocimum gratissimum and Xylopia acutiflora. Regarding the consensus among key informants, ICF values were low (<0.5), however category of infectious and parasitic diseases obtained the best agreement (ICF = 0.42). Following the local experts, 4 types of plants availability were distinguished: Abundant plants easy to collect, abundant plants difficult to harvest, scarce plants and endangered plants.

CONCLUSIONS

Despite the virtual disappearance of natural formations in Ehotile land, medicinal plants are important in the Ehotile health system. Medicinal plants are known and used alone or in addition to medical prescriptions to treat several ailments. However, some of them are becoming rare, and it is feared that this scarcity will result in the inevitable loss of associated knowledge and practices.

Anti-trypanosomal activity of African medicinal plants: a review update

ETHNOPHARMACOLOGICAL RELEVANCE

African trypanosomiasis is one of the neglected tropical diseases caused by different species of trypanosomes that affect both human and livestock with devastating consequences in the continent. Most of the affected populations commonly use traditional medicinal plants for the treatment of the disease. Consequently, this prompted ethnopharmacological research activities on the anti-trypanosomal activity of a number of these African medicinal plants in order to validate their ethnomedicinal use. Furthermore, such studies could lead to the identification of chemical leads for the development of newer anti-trypanosomal agents from those plants. This review aims to provide updated information on the ethnopharmacological evidence of African medicinal plants with anti-trypanosomal activity.

METHODS

Literature was collected via electronic search (PubMed, Sciencedirect, Medline and Google Scholar) from published articles that report on the in vitro or in vivo anti-trypanosomal activity of plants that were collected from different parts of Africa.

RESULTS

African medicinal plants investigated for in vitro and in vivo anti-trypanosomal activity from January 1993 to October 2013 are systematically compiled and all the in vivo studies are critically discussed. A total of 264 plant species belonging to 79 families were investigated for anti-trypanosomal activity. However, only 48 bioactive anti-trypanosomal compounds were successfully isolated in pure forms. Furthermore, some of the plants were investigated for possible ameliorative effects on the trypanosome-induced pathological changes out of which 18 plants were reported to be effective while a few others were not. In spite of interesting preclinical ethnopharmacological evidence for anti-trypanosomal activity, not a single African medicinal plant was investigated in a clinical study.

CONCLUSION

Several African medicinal plants have demonstrated promising anti-trypanosomal effects but the studies on the anti-trypanosomal potentials of these plants are not taken beyond proof of concept stage. It is hoped that the article would stimulate future clinical studies because of the paucity of knowledge in this area.

A bioactivity versus ethnobotanical survey of medicinal plants from Nigeria, west Africa

Traditional medicinal practices play a key role in health care systems in countries with developing economies. The aim of this survey was to validate the use of traditional medicine within local Nigerian communities. In this review, we examine the ethnobotanical uses of selected plant species from the Nigerian flora and attempt to correlate the activities of the isolated bioactive principles with known uses of the plant species in African traditional medicine. Thirty-three (33) plant species were identified and about 100 out of the 120 compounds identified with these plants matched with the ethnobotanical uses of the plants.

Saponins-rich fraction of Calotropis procera leaves elicit no antitrypanosomal activity in a rat model

OBJECTIVE

To examine the in vitro and in vivo anti-Trypanosoma evansi (T. evansi ) activity of saponins-rich fraction of Calotropis procera (cpsf) leaves as well as the effect of the fraction on the parasite-induced anemia.

METHODS

A 60-minutes time course experiment was conducted with various concentrations of the fraction using a 96-well microtiter plate technique, and subsequently used to treat experimentally T. evansi infected rats at 100 and 200 mg/kg body weight. Index of anemia was analyzed in all animals during the experiment.

RESULTS

The cpsf did not demonstrate an in vitro antitrypanosomal activity. Further, the cpsf treatments did not significantly (P>0.05) keep the parasites lower than the infected untreated groups. At the end of the experiment, all T. evansi infected rats developed anemia whose severity was not significantly (P>0.05) ameliorated by the cpsf treatment.

CONCLUSIONS

It was concluded that saponins derived from Calotropis procera leaves could not elicit in vitro and in vivo activities against T. evansi.

Phenolics-rich fraction of Khaya senegalensis stem bark: antitrypanosomal activity and amelioration of some parasite-induced pathological changes

CONTEXT

The stem bark of Khaya senegalensis A. Juss (Meliaceae) is currently used for the treatment of trypanosomiasis by traditional practitioners in Nigeria.

OBJECTIVES

The present study investigated the anti-Trypanosoma brucei brucei activity of phenolics-rich fraction of K. senegalensis (pfks) and its ameliorative effects on trypanosome-induced pathological changes.

MATERIALS AND METHODS

The fraction was initially analyzed by gas chromatography-mass spectrometry (GC-MS). A 60 min time course experiment was conducted with various concentrations of the fraction using a 96-well microtiter plate technique and was further used to treat T. brucei infected rats at 100, 200 and 300 mg/kg body weight (BW). Indices of anemia as well as hepatic and renal functions were analyzed in all experimental animals at the end of the experiment.

RESULTS

The GC-MS analysis of the pfks revealed that the most abundant phytochemicals are phloroglucinol (40.56%) and 3,4-(dihydroxyphenyl) acetic acid (41.76%). The fraction showed a concentration dependent in vitro antitrypanosomal activity. Interestingly, the fraction completely eliminated the parasites from the bloodstream of infected rats without relapse during the experimental period at the dose of 300 mg/kg BW and also kept the parasites consistently lower at 100 and 200 mg/kg BW than that was recorded in the untreated infected rats. Furthermore, the severity of T. brucei-induced anemia and hepatic damage was significantly (p < 0.05) ameliorated in the 300 mg/kg BW treatment group whereas the parasite-induced renal damage was significantly (p < 0.05) ameliorated in all treatment groups.

CONCLUSION

Data from this study may suggest that phenolics play an important role in the antitrypanosomal activity of K. senegalensis.

Total synthesis, stereochemical assignment, and biological activity of chamuvarinin and structural analogues

A highly stereocontrolled synthesis of (+)-chamuvarinin has been completed in 1.5% overall yield over 20 steps. The key fragment coupling reactions were the addition of alkyne 8 to aldehyde 7 (under Felkin-Anh control), followed by the two step activation/cyclization to close the C20-C23 2,5-cis-substituted tetrahydrofuran ring and a Julia-Kocienski olefination at C8-C9 to introduce the terminal butenolide. The inherent flexibility of our coupling strategy led to a streamlined synthesis with 17 steps in the longest sequence (2.2% overall yield), in which the key bond couplings are reversed. In addition, a series of structural analogues of chamuvarinin have been prepared and screened for activity against HeLa cancer cell lines and both the bloodstream and insect forms of Trypanosoma brucei, the parasitic agent responsible for African sleeping sickness.

In-silico investigation of antitrypanosomal phytochemicals from Nigerian medicinal plants

BACKGROUND

Human African trypanosomiasis (HAT), a parasitic protozoal disease, is caused primarily by two subspecies of Trypanosoma brucei. HAT is a re-emerging disease and currently threatens millions of people in sub-Saharan Africa. Many affected people live in remote areas with limited access to health services and, therefore, rely on traditional herbal medicines for treatment.

METHODS

A molecular docking study has been carried out on phytochemical agents that have been previously isolated and characterized from Nigerian medicinal plants, either known to be used ethnopharmacologically to treat parasitic infections or known to have in-vitro antitrypanosomal activity. A total of 386 compounds from 19 species of medicinal plants were investigated using in-silico molecular docking with validated Trypanosoma brucei protein targets that were available from the Protein Data Bank (PDB): Adenosine kinase (TbAK), pteridine reductase 1 (TbPTR1), dihydrofolate reductase (TbDHFR), trypanothione reductase (TbTR), cathepsin B (TbCatB), heat shock protein 90 (TbHSP90), sterol 14α-demethylase (TbCYP51), nucleoside hydrolase (TbNH), triose phosphate isomerase (TbTIM), nucleoside 2-deoxyribosyltransferase (TbNDRT), UDP-galactose 4' epimerase (TbUDPGE), and ornithine decarboxylase (TbODC).

RESULTS

This study revealed that triterpenoid and steroid ligands were largely selective for sterol 14α-demethylase; anthraquinones, xanthones, and berberine alkaloids docked strongly to pteridine reductase 1 (TbPTR1); chromenes, pyrazole and pyridine alkaloids preferred docking to triose phosphate isomerase (TbTIM); and numerous indole alkaloids showed notable docking energies with UDP-galactose 4' epimerase (TbUDPGE). Polyphenolic compounds such as flavonoid gallates or flavonoid glycosides tended to be promiscuous docking agents, giving strong docking energies with most proteins.

CONCLUSIONS

This in-silico molecular docking study has identified potential biomolecular targets of phytochemical components of antitrypanosomal plants and has determined which phytochemical classes and structural manifolds likely target trypanosomal enzymes. The results could provide the framework for synthetic modification of bioactive phytochemicals, de novo synthesis of structural motifs, and lead to further phytochemical investigations.

Evaluation of the acute and sub acute toxicity of Annona senegalensis root bark extracts

OBJECTIVE

To investigate the safety profile of Annona senegalensis (A. senegalensis).

METHODS

Dried powdered root-bark of A. senegalensis was prepared by Sohxlet extraction using methanol-methylene chloride (1:1) solution and concentrated to obtain the methanol-methylene chloride extract (MME). MME was fractionated to obtain the n-hexane (HF), ethylacetate (EF) and methanol (MF) fractions. Acute toxicity (LD(50)) test was performed with MME, HF, EF and MF in mice by oral route. The sub acute toxicity studies were performed in rats after 14 days of MME administration while haematological and biochemical parameters were monitored.

RESULTS

Medium lethal (LD(50)) values of 1,296, 3,808, 1,265 and 2,154 mg/kg were obtained for the MME, MF, HF and EF, respectively. The sub-acute toxicity studies indicated a significant (P<0.05) increase in the body weight of both the treated rats and the control. The haematological tests indicated no change in the packed cell volume values but a significant (P<0.05) increase in the total WBC count at 100 and 400 mg/kg doses. The differential analysis showed a decrease in the nutrophils and a non-significant increase in the lymphocyte counts. The liver transaminase enzymes, alanin transaminase and aspartate transaminase showed no significant increase compared to the control. Histopathological examination of the liver sections also indicted no obvious signs of hepatotoxicity except with the 400 mg/kg dose that showed degeneration and necrosis of the hepatocytes.

CONCLUSIONS

These results indicated that the root bark extracts of A. Senegalensis are safe at the lower doses tested, and calls for caution in use at higher doses in treatment.

In vivo antitrypanosomal effects of some ethnomedicinal plants from Nupeland of north central Nigeria

Four medicinal plants Acacia nilotica, Bombax buonopozense, Terminalia avicennioides and Zanthoxylum zanthoxyloides traditionally used for treatment of sleeping sickness in Nupeland were investigated for in vivo antitrypanosomal activity. Methanol extracts of different parts of each plant (stem barks and fruits) were obtained and evaluated for their in vivo antitrypanosomal activities against Trypanosoma brucei brucei. Phytochemical screening of the methanol extracts of each plant were performed by standard procedures. Methanol extracts of A. nilotica (stem bark), B. buonopozense (stem bark), T. avicennioides (round fruit) and Z. zanthoxyloides (stem bark) were effective on trypanosomes. The extracts of A. nilotica and B. buonopozense exhibited antitrypanosomal effects at 200 and 300 mg/kg body weight respectively. Doses were able to clear the parasites from circulation within 6 and 7 days of treatment respectively with prolonging survival period of up to 30 days. While the extracts of T. avicennioides and Z. zanthoxyloides showed trypanostatic effects and could not clear the parasites completely. The methanol extracts of these plants contain metabolites that are associated with antitrypanosomal effects; therefore, these medicinal plants may be sources of new compounds that may be active against T. b. brucei. This study has also justified the claim that some medicinal plants of Nupeland possess antitrypanosomal activity and could be useful in the management of trypanosomiasis.