IN VITRO ANTIBACTERIAL ACTIVITY OF HEXANE, CHLOROFORM AND METHANOLIC EXTRACTS OF DIFFERENT PARTS OF ACRONYCHIA PEDUNCULATA GROWN IN SRI LANKA.

This study accessed the antibacterial potential in vitro of hexane, chloroform and methanol extracts made from leaves, stem bark, flowers, seeds or roots of Sri Lankan grown Acronychia pedunculata plant against two Gram positive bacteria, Staphylococus aureus (ATCC 25923) and Bacilus cereus (ATCC 11778), and two Gram negative bacteria, Pseudomonas aeruginosa (ATCC 9027) and Escherichia coli (ATCC 35218), using agar disc diffusion bioassay technique. The results showed that none the of the extracts provoked an antibacterial action against the two Gram negative bacteria P. aeruginosa and E. coli. Conversely, compared to reference drug, Gentamicin, varying magnitudes of antibacterial activity (concentration: 300 mg/disc) ranging from zero to mild to moderate to strong antibacterial activity was evident with the three solvent systems made from different parts of the plant against the two Gram positive bacteria S. aureus and B. cereus. All the three flower extracts excerted marked antibacterial activity against both S. aureus and B. cereus. The highest antibacterial activity was exhibited by methanol flowers extract (inhibition zone: 13.8±0.32mm), with a Minimum inhibitory value of 32mg/ml, against B. cereus. The overall order of potency against S. aureus was, chloroform flowers> chloroform seeds > hexane leaves > chloroform leaves > methanol flowers> hexane flowers> methanol seeds. And against B. cereus was methanol flowers> hexane leaves > hexane flowers> chloroform leaves >chloroform flowers >chloroform seeds > hexane roots > chloroform roots > methanol seeds chloroform stem barks = hexane stem barks. These are all novel findings for A. pedunculata found in Sri Lanka and elsewhere. It is concluded that novel, potent and cost effective antibacterial agent/s, especially, against Gram-positive bacterial pathogens may be developed from flowers, seeds and leaves of A. pedunculata.