Antimicrobial Activity of Seed Extracts from Albizia bernieri E. Fourn. (Fabaceae)

This work aimed at assessing the antimicrobial activity of Albizia bernieri seed extracts. Methanol extract (SME), alkaloids extracted under basic (Alk1) and acidic (Alk2) conditions, polar saponosides (Sap1) and less polar saponosides (Sap2) obtained by n-butanol fractionation were used. Their activities were tested against 9 pathogenic germs including 4 Gram (+) bacteria, 5 Gram (-) bacteria and 1 yeast using disc diffusion and microdilution methods. Regardless the method used to assess the antimicrobial activity, all extracts were efficient but their effects depended upon the germs tested. They all displayed a broad spectrum activity. Alkaloids were by far the most efficient with an excellent effect (Minimum Inhibitory Concentration or MIC<100μg/ml) against all germs tested. Streptococcus pneumoniae, Streptococcus pyogenes, Clostridium perfringens and Candida albicans were the most sensitive with MICs less than 10 μg/ml. SME and Sap 2 had moderate or low effects (MIC between 100 and 1000 μg/ml) and Sap1 was the less efficient (MIC ≥1000 μg/ml). All the extracts exerted bactericidal or fungicidal action on all sensitive germs. These preliminary results revealed antimicrobial activity of Albizia bernieri seeds that could be used to treat different infectious diseases and might lead to the development of pharmaceutical agents.