Evaluation of the in vitro antibacterial activity of the solvent fractions of the leaves of Rhamnus prinoides L’Herit (Rhamnaceae) against pathogenic bacteria

Abstract

BackgroundMedicinal plants play great roles in the treatment of various infectious diseases. Rhamnus prinoides is one of the medicinal plants used traditionally for treatment of bacterial diseases. The antibacterial activity of the crude extract of the plant had been shown by a previous study, but this study was undertaken to further the claimed medicinal use of the plant by screening its solvent fractions for the said activity so that it could serve as a basis for subsequent studies.MethodsThe solvent fractions of the plant were obtained by successive soxhlet extraction with solvents of increasing polarity, with chloroform and methanol, followed by maceration of the marc of methanol fraction with water. The antibacterial activity of the solvent fractions was evaluated on seven bacterial species using agar well diffusion method at different concentrations (78 mg/well, 39 mg/well and 19.5 mg/well) in the presence of positive and negative controls. The minimum inhibitory concentration of the solvent fractions was determined by micro-broth dilution method using resazurin as indicator.ResultMethanol and chloroform fractions revealed antibacterial activities against the growth of test bacterial strains with varying antibacterial spectrum and the susceptible bacterial species were Staphylococcus aureus, Streptococcus pyogen, Streptococcus pneumoniae and Salmonella typhi. The average minimum inhibitory concentration value of the methanol and chloroform fractions ranged from 8.13 mg/ml to 32.5 mg/ml and from 8.13 mg/ml to 16.25 mg/ml, respectively.ConclusionThe methanol and chloroform fractions demonstrated significant antibacterial activities against the growth of pathogenic bacteria but the aqueous fraction did not reveal antibacterial activity against any of the test bacteria.

Antibacterial Activity of Rhamnus prinoides extracts against Staphylococcus aureus and Escherichia coli

“…On the other hand, results of the current study were contrasted with that of [6] and [26] who reported aqueous extract of Rhamnus prinoides leaves was found to be devoid of antibacterial activities against all the test bacterial strains regardless of the concentrations. Another study conducted by [3] reported that, water extracts of Avicennia marina did not give any inhibition against Staphylococcus sp.…”

“…Among extracts of the plant used in the study, the ethanol extract of Rhamnus prinoides fruits showed the maximum zone of inhibition which was in line with the study of [33] The current results were disagreed with that of [26] aureus were 400 mg/ml and 200 mg/ml respectively [6].…”

“…In the case of chloroform extract, the lowest MIC value was found with Rhamnus prinoides fruits (2.08 mg/ml) against standard strains and clinical isolates of S. aureus and Rhamnus prinoides leaves (50mg/ml) against standard strains and clinical isolates of E. coli. These results were disagreed with that of [26] who reported that the MIC value for chloroform fraction of gesho against standard strains and clinical isolates of S. aureus were 8.13 mg/ml and 16.25 mg/ml respectively, while this fraction was found to be devoid of MIC against standard strains and clinical isolates of E. coli at the same The present study also showed that, the lowest MBC value was found with water extracts of Rhamnus prinoides fruits (50 mg/ml) and the highest MBC value was found with and Rhamnus prinoides leaves (100 mg/ml) against all tested bacteria. MBC of water extract of E. elaterium fruit was (128) against E. coli [33] which was higher than the current study.…”

“…Ethanol extract of Rhamnus prinoides fruit was showed the lowest MBC (2.08mg/ml) against standard strains and clinical isolates of S. aureus, [33] reported that ethanol extract of Mandragora autumnalis fruits showed MBC value of 16 [22]. The previous study by [26] showed that the MBC value for methanol fraction of Rhamnus prinoides leaves against S.…”

“…Rhamnus prinoides leaves against standard strains and clinical isolates of E. coli. According to [26] the…”