In Vitro Antibacterial Activity and Toxicity Study of Eucalyptus Camaldulensis Leaves Extracts against Clinical Isolates of Salmonella Sp

ABSTRACT
Eucalyptus camaldulensis 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 E. camaldulensis leave extracts against clinical isolates of salmonella species. The E. camaldulensis leaves were extracted separately and successively with ethanol, water and methanol using percolation method. The extracts were tested in vitro for activity against clinical isolates of Salmonella typhi and Salmonella paratyphi using agar well diffusion and broth dilution methods. The zones of inhibition, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. The in vitro antimicrobial screening revealed that the extracts exhibited varying activities against the different isolates with zones of inhibition ranging from 7mm-24mm, MIC ranging from 62.5µg/ml - 125µg/ml and MBC of 125µg/ml -500µg/ml. The highest activity observed with Eucalyptus camaldulensis leaves extracts was 24mm against S. paratyphi A. MIC of 62.5µg/ml against Salmonella typhi, and MBC of 125µg/ml against, 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, and terpenes detected in the leaves. The toxicity study carried out revealed that the highest value for LD50 of 1308.872 which shows non toxic property was in Eucalyptus camaldulensis leaves aqueous extract against hatched brine shrimps. However, ethanolic and methanolic extracts have LD50 less than 1000 hence considered moderately toxic. All extracts shows activity against the test organism in accordance with extract concentration. All extracts showed antibacterial property against the test organism in accordance with extract concentration. The study also showed that E. camaldulensis leave is a potential source of antimicrobial compound and has potential use for health benefits.


Keywords: Antibacterial, Eucalyptus camaldulensis, Zone of Inhibition, Toxicity.