GUIERA-SENEGALENSIS GMELIN,JF (COMBRETACEAE) - BIOLOGICAL-ACTIVITIES AND CHEMICAL INVESTIGATION

Guiera senegalensis J. F. Gmelin (Combretaceae) leaves are used in Afr ican traditional medicine for gastrointestinal disorders, cough and to pically for wound healing. This paper regards the evaluation of antira dical, antielastase, antimicrobial, genotoxic and antimutagenic activi ties of the leaf extracts and the determination of chemical structure of the elastase inhibitors. Antimicrobial activity was tested against Gram positive and negative bacteria, moulds and yeasts. Genotoxic pote ntial was assayed with Bacillus subtilis rec-assay and Salmonella-micr osome test. The latter was used also for determining antimutagenic act ivity. Antiradical properties were evaluated as inhibition of ADP-Fe2 induced lipoperoxidation in rat liver microsomes. Porcine pancreatic elastase was used to test enzyme inhibition. The methanolic extract wa s fractionated with dichloromethane, n-butanol and water and these fra ctions were tested for the above mentioned activities. The crude extra ct possessed a;mild antimicrobial effect only on Gram positive bacteri a (MIG 0.8-1.5 mg/ml) and the effect was associated to dichloromethane and n-butanol fractions. The crude extract and the dichloromethane an d n-butanol fractions were weakly genotoxic but showed also a signific ant antimutagenicity. Inhibition of lipoperoxidation was assignable ma inly to the n-butanol fraction. Elastase was inhibited (IC50 181 mu g/ ml) and the inhibition was retained in the water soluble fraction (IC5 0 37 mu g/ml). The compounds responsible for the enzyme inhibition wer e a mixture of proanthocyanidins constituted predominantly by (-)-epic atechin and (-)-epigallocatechin units. The mean degree of polymerizat ion was 2-6.