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.

[Toxocological study of Guiera senegalensis Lam (Combretaceae)]. / Etude toxicologique de Guiera senegalensis Lam (Combretaceae).

The study was based on an aqueous extract derived from a 60 degrees ethanolic tincture containing 0.032 g of dry matter per ml. The leaves of Guiera senegalensis Lam (Combretaceae) were collected in December 1991 at Nguekhokh a village within 20 km from Mbour (Senegal). The extract was administered for six months through daily forced-feeling at 2 g/kg to Wistar male and female rats whose weight at the beginning of the experiment tanged between 140 g and 180 g. The urine was analysed during the study and the animals were weighed every four weeks. At the end of the experiment, the animals were slaughtered and various analyses carried out. Haematological features in relation with erythropoiesis, haemoglobinogenesis and leucopoiesis, were studied in relation with renal and hepatic functions; biochemical features too. Some organs (heart, lungs, kidneys, brain, cerebellum, spleen and liver) were removed and examined in order to detect possible lesions following the experiment. Judging by the results, Guiera senegalensis Lam (Combretaceae), as used in the experiment, did not show any significant toxicity.