Antibacterial Effects of Chemical Constituents Isolated from the Roots of Cordia myxa (Boraginaceae) on Salmonella typhi (Enterobacteriaceae)

Abstract

Cordia myxa is a Cameroonian pharmacopoeia traditional plant. It belongs to the Boraginaceae family, which different parts are used in the treatment of various bacterial infections. The phytochemical screening carried out on the Cordia myxa species indicates the presence of alkaloids, triterpenes, steroids, carbohydrates, flavonoids and saponins. Our investigations on the roots of this plant allowed us to isolate two triterpenes from the ethyl acetate extract, which crystallize in the Hex/AcEt [2/8] solvent system; (23R) campesta-9 (11), 24 (30) diene-18,23-diol 3-O-α-rhamnopyranoside (compound 1) and alphitolic acid (compound 2). The isolation and characterization of these compounds were carried out respectively by silica gel chromatography and by NMR (1D, 2D) spectral analysis. Compound 1and 2 were tested on the in vitro growth of E.coli and Salmonella typhi using the Muller-Hinton solid medium disc method. The results revealed that these compounds have a dose-dependent antibacterial activity on Salmonella typhi. However, compound 2 had a better antibacterial potential on the Salmonella strain (18.6±0.6mm, 30mg/ml) with the MIC=0.25mg/ml than the compound 1 (14.5±0.4mm, 30mg/ml,) with the MIC=0.44mg/ml. Few classes of antibiotics have been tested, to look for those with the best results and compare the different doses of our compounds. The two compounds did not have any effect on E. coli.