Antimicrobial lectin from S chinus terebinthifolius leaf

Aims Schinus terebinthifolius leaves are used for treating human diseases caused by micro‐organisms. This work reports the isolation, characterization and antimicrobial activity of S . terebinthifolius leaf lectin ( S te LL ). Methods and Results The isolation procedure involved protein extraction with 0·15 mol l −1 NaCl, filtration through activated charcoal and chromatography of the filtrate on a chitin column. Ste LL is a 14‐ kD a glycopeptide with haemagglutinating activity that is inhibited by N ‐acetyl‐glucosamine, not affected by ions ( C a 2+ and M g 2+ ) and stable upon heating (30–100°C) as well as over the pH 5·0–8·0. The antimicrobial effect of Ste LL was evaluated by determining the minimal inhibitory ( MIC ), bactericide ( MBC ) and fungicide ( MFC ) concentrations. Lectin was active against E scherichia coli, K lebsiella pneumoniae , P roteus mirabilis , P seudomonas aeruginosa, S almonella enteritidis and S taphylococcus aureus . Highest bacteriostatic and bactericide effects were detected for S alm. enteritidis ( MIC : 0·45 μg ml −1 ) and Staph. aureus ( MBC : 7·18 μg ml −1 ), respectively. Ste LL impaired the growth ( MIC : 6·5 μg ml −1 ) and survival ( MFC : 26 μg ml −1 ) of C andida albicans . Conclusions Ste LL , a chitin‐binding lectin, purified in milligram quantities, showed antimicrobial activity against medically important bacteria and fungi. Significance and Impact of the Study Ste LL can be considered as a new biomaterial for potential antimicrobial applications.