title: Antibacterial activities of essential oils extracted from leaves of Murraya koenigii by solvent-free microwave extraction and hydro-distillation.
abstract: Solvent-free microwave extraction (SFME) for the isolation of essential oil from leaves of Murraya koenigii L. (Rutaceae) has been compared with the conventional hydro-distilled oil (HD) in terms of yield, composition, antioxidant activity, and antibacterial activity against Listeria innocua. The yield of essential oil obtained from 30 min of SFME was similar to that of HD for 180 min. By GC-MS analysis, the major compounds of the essential oil extracted by SFME, which were obtained in somewhat lower amounts than in the essential oil obtained by HD, were alpha-copaene (44.3%), beta-gurjunene (25.5%), isocaryophyllene (12.1%), beta-caryophyllene (8.7%) and germacrene D (2.9%). The content of oxygenated terpenes, slightly higher for the SFME-essential oil (2.3%) than the HD-essential oil (1.4%), were much lower than that of nonoxygenated terpenes in both oils. DPPH radical scavenging activities of both essential oils were relatively low (10%-24%). Complete inhibition of growth of L. innocua was observed with both SFME and HD essential oils, at 400 and 600 microg/mL (minimum inhibitory concentration), respectively. The SFME-essential oil at 300 microg/mL provided 92% inhibition, indicating its potential as a natural antimicrobial agent.
authors.affiliation: Department of Environmental Sciences, Nova Scotia Agricultural College, P.O. Box 550, Truro, Nova Scotia, Canada B2N 5E3.
authors.forename: Naciye
authors.initials: N
authors.lastname: Erkan
authors.forename: Zhou
authors.initials: Z
authors.lastname: Tao
authors.forename: H P Vasantha
authors.initials: HP
authors.lastname: Rupasinghe
authors.forename: Burcu
authors.initials: B
authors.lastname: Uysal
authors.forename: Birsen S
authors.initials: BS
authors.lastname: Oksal
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D057168:Distillation; D032101:Murraya / Q000737:chemistry*; D009822:Oils, Volatile / Q000032:analysis / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D052617:Solid Phase Microextraction
chemical_list: D000900:Anti-Bacterial Agents; D009822:Oils, Volatile