Étude phytochimique et activités antimicrobiennes des extraits organiques de Oxalis barrelieri L.(Oxalidaceae)

Abstract

The research of molecules with bactericidal activity is always current event with increase of multi resistance. In traditional medicine, plants are use without knowing the molecules responsible of the desire effect. Oxalis barrelieri for example is use in the treatment of gastric ulcers. This study aims to identify the various families of chemical compounds contained in the plant Oxalis barrelieri and tits antibacterial effects on five bacterial strains (Enterobacter BM67, Escherichia coli ATCC8739, Enterobacteraerogenes ATCC13048, Klebsiella pneumonia ATCC11296, Enterobacter cloacae K2) were carried out. With the various tests of solubility means, carried out by Thin Layer Chromatography (TLC), two solvents with knowing mixture of solvent methanol/methylene chloride (1/1) and methanol were regarded as better solvents of extraction of the plant; thereafter, 1000g of powder of Oxalis barrelieri was extracted by maceration successively with methanol/chloride methylene (1/1) and with methanol to afford 12,7g and 2,18g of extracts from 1, 27% and 0, 22% yields respectively. These extracts were subjected to the phytochemical screening tests and the results showed the richness of both extracts in triterpenes, phenols, tanins, saponins, and lipids, and their absence in alkaloids; the extract with methanol was quite rich in flavonoïdes while the extract with the methanol mixture/methylene chloride (1/1) didn’t possess any at all. The antimicrobial activities tests of the two extracts were carried out on the five strains of bacteria named above by the method of diffusion on gélose Muller-Hinton, with ciprofloxacine as reference. The results showed that these extracts do not inhibit the growth of all the bacterias tested; thus its empirical use for the trement of gastric ulcers is not link to a bactericidal effect.