ANTIBACTERIAL EFFECT AND PHYTOCHEMICAL ANALYSIS OF THE SHOOT SYSTEM OF RUBUS CANESCENS DC. GROWING IN LEBANON

Abstract

The misuse of antibiotics followed by improved fitness of resistant strains of infectious microorganisms hindered the efficacy of many known antimicrobial agents, and fueled research for the discovery of novel remedies. The current study aims at assessing the antimicrobial activity and understanding the mechanism of action of Rubus canescens DC. growing wild in Lebanon, as well as qualitatively determining its phytochemical profile. The antibacterial activity, MIC, and MBC of the extracts were evaluated by two-fold dilution. Time-kill curves were plotted to assess the bactericidal activity of the R. canescens DC. extracts against the growth of microorganisms, and TEM images were collected to confirm such effect. Overall, the extracts exhibited good antibacterial activity against MRSA and E. coli but not against S. pneumoniae and K. pneumoniae as determined by measuring the inhibition zones in plate-diffusion assays. TEM images of treated microorganisms revealed that the R. canescens DC. extracts induced irreversible deformations and damage to the cell membranes of the microorganisms leading to the leakage of cytoplasmic components and eventual cell death. Analysis of Time-Kill curves indicated that the extracts induced 100% killing of the test microorganisms within 10-18 h at the respective MBC. Finally, qualitative phytochemical analysis was conducted to decipher the active ingredients in the plant extracts.The current study reports the first data on the antimicrobial activity of different parts of R. canescens DC. Such promising data opens new avenues for broader assessment of the pharmacological profile of the scarcely investigated R. canescens DC.