Efficacy of Bark and Leaf Extracts of Zizyphus rugosa Lam. Against Clinical Bacterial IsolatesAuthor(s): Vinayaka KS, Shravanakumar S, Roopashree AC, Sandeep Otari M, Praveen Kumar SV, Swathi D and Prashith Kekuda TR
In the present study, the phytoconstituents and antibacterial activity of methanol, chloroform and hexane extracts of bark and leaf of Zizyphus rugosa Lam. was investigated against two pathogens, namely Staphylococcus aureus and Escherichia coli, isolated fromclinical specimens were studied. Preliminary phytochemical tests showed the presence of tannins, alkaloids, steroids, saponins and flavonoids in methanol extract of leaves while terpenoids, alkaloids, steroids and saponins were detected in bark extract.All the solvent extracts exhibited antibacterial activity as revealed by zone of inhibition formed around the well. Among isolates subjected, marked inhibition of S. aureus was observed at lesser concentration than E. coli. The leaf extracts were found to inhibit test bacteria at low concentration than bark extracts. Overall, among extracts tested, methanol extract was found to be more potent than other extracts.Methanol and chloroform extracts of leaf and bark inhibited S. aureus at a concentration of 2.5mg/ml while hexane extract revealed MIC of 5mg/ml concentration. The antimicrobial activity of solvent extracts of leaf and bark of Z. rugosa might be possibly due to the presence of the phytoconstituents in the extracts. Since the study involved the clinical isolates, which are among most noted antibiotic resistant bacteria, the extracts could be useful in the treatment of the infections caused by these bacteria. Further experiments are to be conducted to isolate active principles from the extracts and to determine in vivo antibacterial efficacy of phytoconstituents against antibiotic resistant clinical pathogens.