Essential oils and bioactivities of Piper betle / Sofea Syahira Ahmad Sufi

The chemical compositions as well as antioxidant and antibacterial activities of the leaves of P. betle collected from Negeri Sembilan, Selangor and Malacca have been studied. The essential oils were extracted by using hydrodistllilation method and the chemical compositions were analysed by using gas chromatography-mass spectrometry (GC-MS). The antioxidant effect was carried out using 2,2- diphenyl-1-picrylhydrazyl radical scavenging assay, while screening for antibacterial activity was performed using disc diffusion method. The essential oils from Negeri Sembilan, Selangor and Malacca yielded 32 (90.6%), 22 (95.8%) and 34 (86.2%) compounds, respectively. All essential oils were dominated by phenylpropanoids (41.5-85.2%) with eugenol being the most abundant compound (24.0-61.1%). The essential oil from Negeri Sembilan was also rich in 4-ally-1,2- diacetoxybenzene (13.9%), chavibetol acetate (12.6%) and germacrene D (9.5%), while the essential oil from Selangor was also contained chavicol (12.2%) and chavibetol acetate (5.9%) as the main compounds. Germacrene D (5.8%), β- caryophyllene (5.2%) and 4-ally-1,2-diacetoxybenzene (5.2%) were also identified in significant amount in the essential oil from Malacca. All investigated oils showed 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity with the IC50 values 50.53 ̶ 126.10 µg/mL. The highest radical scavenging activity was showed by the essential oil from Selangor (IC50 50.53 µg/mL). The essential oil from Selangor also demonstrated the highest antibacterial activity toward S. aureus and E. coli with the inhibition zones 25.00 and 21.60 mm, respectively