title: In vitro antibacterial activity of Psidium guajava Linn. leaf extract on clinical isolates of multidrug resistant Staphylococcus aureus.
abstract: In the present study, antibacterial activity of aqueous and organic extracts of Psidium guajava leaves was evaluated against multidrug resistant (MDR) clinical isolates of Staphylococcus aureus strains collected from hospitals in northern (Malabar region) Kerala. The strains which exhibited resistance against all the antibiotics tested was selected for antibacterial assays. Minimum inhibitory concentration (MIC) for methanolic and aqueous extracts was found to be 625 ug/ml and 7.5 mg/ml, respectively. Minimum bactericidal concentration (MBC) recorded for methanolic and aqueous extracts was 1.25 and 12.5 mg/ml, respectively. Methanolic extract at minimum bactericidal concentration inhibited the growth of MDR strain by 80%. Time-kill assay revealed that methanolic extract (4 mg/ml) killed MDR bacteria within 10 hr. Total polypeptide profiling of bacterial cultures by SDS-PAGE indicated a high degree of protein degradative activity of the extract. Finally, a human RBC based haemolytic assay showed absence of haemolysis even at concentrations higher than that of MBC, advocating thereby its safety in therapeutic use.
authors.affiliation: School of Health Sciences, University of Calicut, Calicut University. P.O, Malappuram 673 635.
authors.forename: K
authors.initials: K
authors.lastname: Anas
authors.forename: P R
authors.initials: PR
authors.lastname: Jayasree
authors.forename: T
authors.initials: T
authors.lastname: Vijayakumar
authors.forename: P R
authors.initials: PR
authors.lastname: Manish Kumar
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004058:Diffusion; D024881:Drug Resistance, Bacterial; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000378:metabolism; D006461:Hemolysis; D006801:Humans; D000432:Methanol / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000378:metabolism*; D013203:Staphylococcal Infections / Q000188:drug therapy*; D013211:Staphylococcus aureus / Q000378:metabolism*; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D010455:Peptides; D010936:Plant Extracts; D014867:Water; D000432:Methanol