Antibacterial potentiality and phytochemical analysis of mature leaves of Polyalthia longifolia (Magnoliales: Annonaceae)

The present study evaluated the antibacterial potentiality of hot aqueous and methanol solvent extract of mature leaves of Polyalthia longifolia (Sonn.) Thwaites (Magnoliales: Annonaceae) against six reference bacteria viz. Staphylococcus aureus MTCC 2940, Bacillus subtilis MTCC 441, Escherichia coli MTCC 739, Klebsiella pneumoniae MTCC 530, Proteus vulgaris MTCC 426 and Enterobacter aerogenes MTCC 111. A sensitivity test performed with commercially available sensitivity test disks resulted in the appearance of multiple drug resistance phenotypes as all the tested bacteria are resistant to amoxycillin, cloxacillin, penicillin G and ampicillin. Most effective antibiotic against bacteria includes ofloxacin against S. aureus and K. pneumoniae; cephalexin against P. vulgaris; ciprofloxacin against E. coli and B. subtilis; kanamycin against E. aerogenes. When antibacterial potentiality of hot aqueous and methanol solvent extract of mature leaves of P. longifolia was evaluated against the bacteria, highest antibacterial activity was observed against K. pneumoniae in both the extracts followed by E. coli in hot aqueous extract and B. subtilis in methanol extract as evident from MIC values. Chromatographic analysis of the methanol extract of P. longifolia revealed the presence of steroids, alkaloids, biterpenoids, carbohydrates, amino acids, essential oil, phenolics and flavonoids as major phytochemicals.