Evaluation of the toxic effects of Albizia mahalao Capuron extracts, a Fabaceae from Madagascar, on different organisms

This work was designed to study the toxic effects of Albizia mahalao extracts on various organisms and explore their possible uses to fight against noxious organisms. Methanolic extracts of leaves (LME), stem (SME) and root (RME) barks, alkaloids (Alk) and saponosides (Sap) from leaves were tested. All extracts were toxic to mice with LD₅₀ values by intraperitoneal route ranging from 69.18 (RME) to 135.52 mg/kg body weight (Alk). By oral route, at doses 5 and 10 times higher than intraperitoneal LD₁₀₀ those extracts were not toxic. LME, SME and RME were toxic to carp alvins, frog tadpoles but not to chicks and mosquito Culex quinquefasciatus larvae. LC₅₀ on carp alvins varied from 63.78 (RME) to 86.89 µg/mL (SME) and LC₅₀ on frog tadpoles from 68.43 (RME) to 153.4 µg/mL (SME). All the methanolic extracts inhibited the germination of 53.8 % of the seed plants tested with inhibition percentages ranging from 20 to 100 %. In previous study, the same Albizia mahalao extracts were found to be efficient against many pathogenic bacteria at low doses. The extracts non-toxicity by oral route allowed envisaging their use to treat some diseases associated with these bacteria.