Polyphenols content and antimicrobial potential of extracts from leaves of Celtis australis

Abstract

The dichloromethane, ethyl acetate, butanol and methanol extracts from leaves of Celtis australis, used to treat different disorders in Moroccan traditional medicine, were screened for their contents of total polyphenols, flavonoïds and condensed tannins and antimicrobial activity against seven bacterial strains (Staphylococcus aureus, Bacillus cereus, Bacillus sp, Listeria ivanovii, Escherichia coli, Citrobacter freundii and Salmonella sp) and three fungi (Candida albicans, Candida tropicalis and Aspergillus niger), using Ampicillin and Fluconazole as references. The antimicrobial activities of plant extracts were assessed by the disc diffusion and minimum inhibitory concentration (MIC) methods. All values are expressed as mean ± SD. The obtained results showed that the butanol extract exhibited significant and dose-dependent antibacterial activity against S. aureus, B. cereus, Bacillus sp and Salmonella sp. The other extracts exerted moderate antibacterial activity, except methanol extract that inhibited significantly Listeria ivanovii. In the same conditions, the butanol, dichloromethane and ethyl acetate extracts showed significant and dose-dependent antifungal activity against all tested fungi, although at different extents, while methanol extract exhibits moderate effect. The plant extracts yielded important polyphenolic contents assessed by total polyphenols, flavonoïds and condensed tannins. A positive linear correlation was established between these compounds and the antimicrobial activity of plant extracts. These results are corroborating the traditional medicine use of Celtis australis which could be a good candidate for further studies.