Survey on medicinal plants traditionally used in Senegal for the treatment of tuberculosis (TB) and assessment of their antimycobacterial activity.

ETHNOPHARMACOLOGICAL RELEVANCE: In West Africa, populations are used to taking traditional medicine as a first aid against common health problems. In this aspect, many plants are claimed to be effective in the treatment of Tuberculosis (TB), which according to the World Health Organization (WHO) remains one of the world's deadliest communicable diseases. AIM OF THE STUDY: The main aim of this study was to identify plants used to treat TB-symptoms by the population of Senegal and to evaluate their possible concomitant use with clinically approved TB-drugs. This approach allowed the selection of plants effectively used in traditional medicine. In order to verify if the usage of some of these plants can be rationalized, the activity of their traditional preparations was assessed with both an intracellular and extracellular antimycobacterial host-pathogen assays. MATERIALS AND METHODS: An ethnopharmacological survey conducted on 117 TB-patients and 30 healers in Senegal from March to May 2014. The questionnaires were focused on the use of medicinal plants to treat common TB -symptoms (cough longer than 2 weeks, fever, night sweats, weight loss and bloody sputum). Local plant names, utilized organs (herbal drugs) and traditional formulations of the plants were recorded. Extracts were prepared by mimicking the traditional decoction in boiling water and screened for their antimycobacterial activity using Mycobacterium marinum, as a validated TB surrogate, and an Acanthamoeba castellanii - M. marinum whole-cell based host-pathogen assay, to detect anti-infective activities. RESULTS: By the end of the survey, nearly 30 plants were cited and the 12 most cited herbal drugs were collected and their usage documented by extensive literature search. Extracts of the chosen herbs were screened with the described assays; with a main focus on traditional formulas (mainly herbal decoctions). Two of the water extracts from Combretum aculeatum and Guiera senegalensis showed significant antimycobacterial activities when compared to the positive control drug (rifampin). These extracts showed no observable toxicity against amoeba host cells (Acanthamoeba castellanii). CONCLUSIONS: This study demonstrates that most of the patients do not concomitantly use plants and TB drugs (~90% of informants) but, instead, most are treated with medicinal plants before they are admitted to a hospital (41%). Interestingly, among the aqueous extracts assayed, two extracts (Combretum aculeatum (Combretaceae) and Guiera senegalensis (Combretaceae)) collected within this survey demonstrate antimycobacterial activities on the validated whole-cell based host-pathogen assay. Both extracts showed significant activities against intracellular and extracellular - M. marinum growth presenting IC50 lower than 0.5mg/ml compared to the reference drug Rifampin (IC50 of 0.4 and 7µg/ml). No toxicity was observed for amoebae cells at concentration until 0.8mg/ml.

A comparative assessment of antiproliferative properties of resveratrol and ethanol leaf extract of Anogeissus leiocarpus (DC) Guill and Perr against HepG2 hepatocarcinoma cells.

BACKGROUND: Epidemiological and experimental evidences have shown cancer as a leading cause of death worldwide. Although the folklore use of plants as a reliable source of health-restoring principles is well-documented, the search for more of such plants that are active against diseases, such as cancer, continues. We report here a laboratory-based evidence of the relevance of an ethanol leaf extract of Anogeissus leiocarpus (A2L) in comparison with resveratrol, a natural polyphenol, in cancer therapy. METHODS: The quantitative assessment of flavonoid and phenolic contents involved quercetin and gallic acid as standards, respectively were determined using spectrophotometry. Cytotoxicity was determined fluorometrically using propidium-iodide-staining method. Antioxidant status, adenosine triphosphate (ATP) levels, caspase activities and mitochondrial integrity were assessed using fluorometry/luminometry. RESULTS: The antioxidant assay demonstrated that A2L possesses a strong antioxidant capacity as compared with the reference compounds, ascorbic acid and butylated hydroxytoluene. This is further buttressed by the significantly high level of phenolics obtained in the quantitative assessment of the extract. A 72-h post-treatment examination indicated that both A2L and resveratrol modulate the proliferation of HepG2 liver carcinoma cells in a time- and concentration-dependent manner. Determination of the total nuclei area, propidium-iodide negative and positive nuclei areas all further buttress the modulation of cell proliferation by A2L and resveratrol with the indication that the observed cell death is due to apoptosis and necrosis at lower and higher concentrations of treatments respectively. At lower concentrations (0.39-3.13 µg/mL), resveratrol possesses higher tendencies to activate caspases 3 and 7. Bioenergetically, both resveratrol and A2L do not adversely affect the cells at lower concentrations (0.39-6.25 µg/mL for resveratrol and 12.5-100.0 µg/mL for A2L) except at higher concentrations (12.5-25.0 µg/mL for resveratrol and 200-800 µg/mL for A2L) which are more pronounced in A2L-treated cells. Furthermore, the antioxidant status of HepG2 cells is not perturbed by resveratrol as compared with A2L. Assessment of 24-h post-treatment mitochondrial function shows that resveratrol is not mitotoxic as compared with A2L which exhibits mitotoxicity at its highest concentration. CONCLUSIONS: Taken together, findings from this study showed that A2L possesses strong antiproliferative activity and its prospect in the management of hepatocellular carcinoma deserves further investigation.

The biological activity and chemistry of the southern African Combretaceae.

AIM OF THE STUDY: Members of the Combretaceae family are widely traded in the traditional medicine market in southern Africa. The family is also used for medicinal purposes in the rest of Africa and Asia for close to 90 medicinal indications. Many of these indications are related to treating infections. This contribution summarizes work done to date and identifies avenues for future research. MATERIALS AND METHODS: Substantial work has already been done on the chemistry of especially Combretum and Terminalia species over many years. During the last decade we have focussed on bio-assay guided isolation of biologically active compounds with the aim of producing new effective antimicrobial products. RESULTS AND DISCUSSION: Methods developed to facilitate this process and data on 25 compounds isolated from 7 species are presented. The large majority of compounds isolated were known, but the biological activities were not known. In practically all cases the antibacterial or antifungal activity of compounds isolated were much lower than expected from the activity of the crude extracts. It appears that synergism plays a role in antimicrobial activity of plant extracts and that the hope of isolating a single compound that can be used as a new agent to address antibiotic resistance has been frustrated. By simple manipulation such as selective extraction the activity of some crude extracts could however, be increased substantially and this offers a new approach to address antibiotic resistance via the herbal medicine industry. Practically all extracts obtained using intermediate polarity extractants had reasonable to very good activity with MICs as low as 40 microg/ml, validating the traditional use for infectious diseases. Aqueous extracts however, generally had hardly any activity. CONCLUSIONS: The Combretaceae contains a diversity of antimicrobial compounds. Because poor people usually have only water available as extractant, it raises the question how plants growing in poor rural communities can be used to treat infections more effectively, and what the mechanism of activity of aqueous extracts used to treat infections in traditional medicine are.