Purification and Toxicity Study of a Saponin from Seeds of Albizia odorata , a Fabaceae from Madagascar

Abstract

In order to continue the research of natural compounds of interest such as pesticides and therapeutic molecules in endemic species of Albizia from Madagascar, potentials of Albizia odorata seed extract were assessed. A toxic saponin (saponoside), named Albodorine, was isolated by extraction with hot ethanol or distilled water followed by purification procedure comprising n-butanol partition, precipitation by aceton-diethyl ether (50/50), Sephadex LH-20 gel chromatography and silica gel chromatography. All these methods were guided by toxicity tests on mice and homogeneity tests by Thin Layer Chromatography (TLC). Albodorine was thermostable, soluble in water and organic solvents and tasted bitter. Its acidic hydrolysis released glucose, arabinose and rhamnose. Tested on different experimental animal models, it was toxic to warm and cold blooded animals. In mouse, when intraperitoneally administered, it caused acute intoxication mainly presented as hyperpnea, ataxia and terminal seizures before the animal died. Its LD50 was about 9 mg/kg of mouse body weight by intraperitoneal route. In different organs, it caused histopathological lesions characterized by vascular congestions and important hemorrhage in liver, lungs and kidneys. In vitro, it reduced the heart rate and force of contraction of isolated rat atria. It had hemolytic activity. Albodorine showed toxicological properties that could be exploited under certain conditions for the control of harmful organisms.