Plants used in Bandjoun village (La'Djo) to cure infectious diseases: An ethnopharmacology survey and in-vitro Time-Kill Assessment of some of them against Escherichia coli

Abstract

An ethnopharmacology survey concerning the medicinal plants used in Bandjoun village (La'Djo) to cure infectious diseases was carried out in three districts of this village. The survey led to the identification of 79 medicinal plants species listed in 41 families. These plants were cited to be use to treat about 25 infectious diseases among which malaria, diarrhea and intestinal-worms were the most cited. Chromolaena odorata, Voacanga africana, Moringa oleifera, Mammea africana, Euphorbia hirta, Psidium guajava, Allium cepa, Enantia chlorantha, Alstonia boonei and Picralima nitida, were the ten most cited plants. Extractions of parts of these last plants were performed in hydro-ethanol (3:7) solvent and then tested in-vitro against an Escherichia coli isolate. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were assessed by microdilution assay and the time-kill assessment was carried out by measure of log reduction in viable cell count, on a period of 48 hours. MIC and MBC determined were ranged between 1.00 and 32.0 mg/mL. Eighty percent (80%) of plant extracts tested have been bactericidal (MBC/MIC = 1 or 2) after 24 hours of incubation. A significant dose-dependent decreasing (P<0.05) in test organisms population was observed in the time with log reduction in viable cell count was ranged between 0.13 log10cfu/mL and 100% of inhibition. This antimicrobial activity has been attributed to metabolites groups in plant extracts namely, Phenols, flavonoids, tannins, coumarins, terpenoids, anthraquinones, cardiac glycosides, anthocyanides and alkaloids. These results obtained against Escherichia coli give a scientific validation to the traditional medical knowledge of Bandjoun-village populations and confirm some of the plants identified like a source of potentially active compounds against infectious diseases.