ANTIBACTERIAL MODE OF ACTION OF BIO-OIL OBTAINED FROM PYROLYSIS OF PINUS DENSIFLORA SIEBOLD & ZUCC. SAWDUST AGAINST FOOD POISON CAUSING STAPHYLOCOCCUS AUREUS ROSENBACH

Abstract

Staphylococcus aureus is a major foodborne pathogen that causes food poisoning. The antibacterial potential of pyrolyzed bio-oil (PBO) manufactured from sawdust of Pinus densiflora against three strains of pathogenic S. aureus (ATCC 49444, ATCC 12600 and ATCC 12692) was evaluated for its mode of action. PBO at 1,000 mu g/disc exhibited strong antibacterial activity against S. aureus ATCC 49444 and ATCC 12600, with 10 - 11 mm inhibition zones. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of PBO ranged from 250 to 500 and 500 to 1,000 mu g/ml, respectively. The mode of action of PBO at the MIC against S. aureus ATCC 49444 revealed its strong impairing effect on membrane permeability in terms of its increased relative electrical conductivity, release of 260 nm absorbing material and leakage of potassium ions (K+), along with its loss of high salt tolerance capacity. Overall, the results of this study suggest that PBO exerts a strong antibacterial effect against S. aureus via disturbance of membrane integrity.