Isolation, purification and characterization of antibacterial principle from Drynaria quercifolia

Abstract

The present study aims to isolate purify and characterize antibacterial principle from Drynaria quercifolia. Investigation started with antibacterial screening of forty-four ferns and phytochemical evaluation of their extracts. Those plants exhibited greater level of antibacterial activity were evaluated further and Drynaria quercifolia was selected for isolating antibacterial principle. The structure of the antibacterial principle was elucidated by UV, IR, MS, 1HNMR, 13CNMR and Elemental analysis. The compound was identified as (1E, 4E)-1,5-bis (4-hydroxy-3,5-dipropyl phenyl) penta-1,4-dien-3- one. The compound displayed meaningful antibacterial activities with MIC value of 31.25 µg/ml against Staphylococcus aureus, and 62.5 µg/ml against Pseudomonas aeruginosa and Escherichia coli. The effectiveness of the compound as antibiotic could not be equated with standard antibiotics except for P. aeruginosa. The result revealed that the compound could be used as an antibiotic like streptomycin against P. aeruginosa, which was found to be resistant against amoxycillin and chloramphenicol. The compound does not have any close structural similarity with any of the commonly used antibiotics. But the phenyl penta-1,4-dien-3-one part of the molecule has got structural similarity with a curcumin analogue (1,5-bis-(2,4-difluorophenyl)penta-1,4-diene-3 one). This compound exhibited anti-tumour and anti-angiogenic properties. A related compound 1,5-bis(4-hydroxy-3-methoxyphenyl)-penta-1,4- dien-3-one and its derivatives have anti-tumour properties.