ANTIBACTERIAL POTENTIALS AND TOXICITY STUDY OF CASSIA OCCIDENTALIS LEAF EXTRACTS AGAINST CLINICAL ISOLATES OF SALMONELLA SP

Abstract

Cassia occidentalis is an important medicinal herb in traditional healthcare practice and has been reported for various biological activities. The objective of the present study was to analyze the antibacterial potentials and toxicity study of cassia occidentalis leave extracts against clinical isolates of salmonella species. C. occidentalis leaves were extracted successively with ethanol, water and methanol as solvent using soxhlet apparatus. The extracts were obtained through rotary evaporator. The extracts were tested in vitro for activity against clinical isolates of Salmonella typhi and Salmonella paratyphi A and Salmonella paratyphi B using agar well diffusion and broth dilution methods. The zones of inhibition, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. The extracts toxicity was investigated using brine shrimp lethality bioassay. The experiments were performed in triplicate and data was analyzed statistically.  The in vitro antimicrobial screening revealed that the extracts exhibited varying activities against the different isolates of Salmonella typhi, S. paratyphi A and S. paratyphi B.  with zones of inhibition ranging from 7 mm-23 mm, MIC ranging from 62.5 µg/ml – 125 µg/ml and MBC of 125 µg/ml -500 µg/ml, The highest activity observed in Cassia occidentalis extracts was 23 mm with methanolic extract against S. paratyphi A and S. paratyphi B. MIC of 62.5 µg/ml and MBC of 125 µg/ml against Salmonella typhi, S. paratyphi A and S. paratyphi B. The activities observed might be due to the presence of the secondary metabolites like, alkaloids, anthraquinones, sterols, glycosides, saponins, terpenes and flavonoids detected in the plant. The toxicity study carried out revealed that the highest value for LD₅₀ shows nontoxic property in extract was 191.639 µg/ml in the aqueous extract while the lowest was LD₅₀ of 30.765 µg/ml which shows high toxic property observed in methanolic extract. The study also showed that C. occidentalis leave is a potential source of antimicrobial compound and has potential use for health benefits.