ANTIBACTERIAL AND ANTIOXIDANT ACTIVITIES OF STEM BARK ESSENTIAL OIL CONSTITUENTS OF LITSEA GLUTINOSA C. B. ROB.

Objective: To evaluate the chemical composition, antibacterial and antioxidant properties of stem bark essential oil of Litsea glutinosa C. B. Rob. Methods: The essential oil isolated from stem bark of L. glutinosa and their chemical composition was analyzed by gas chromatography coupled with mass spectrometry detector. The in vitro antibacterial activity of the stem bark essential oil was investigated against eight human pathogenic bacterial clinical isolates using agar disc diffusion method and MIC value was determined by modified resazurin microtitre-plate assay. The antioxidant activity of essential oil was measured by 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH), 2, 2-azinobis-3-ethylbenzothiazoline-6-sulphonate radical cation (ABTS) and β-carotene bleaching assay. Results: GC-MS analysis of stem bark essential oil resulted in the identification of 37 compounds, off which 9,12-octadecadienoic acid (62.57%), hexadecanoic acid (12.68%), stigmast-5-en-3-ol (6.87%) and vitamin E (2.51%) were the main constituents representing 84.63% of the oil. The determination of in vitro antibacterial activity of stem bark essential oil resulted in significant inhibition zone (15.00±0.57 mm) and MIC value (0.15±0.15×10 -2 mg/ml) against the pathogenic bacteria Vibrio cholera followed by Pseudomonas aeruginosa and Salmonella typhi. The results of DPPH radical scavenging (IC 50 :4.540±0.06 µg/ml), ABTS (IC 50 :256.02±0.06 µg/ml) and β-carotene bleaching assay (%I: 78.51±0.42 % ) showed significant in vitro antioxidant property. Conclusion: L. glutinosa stem bark essential oil showed potential antibacterial activity against the Vibrio cholera . The results of this investigation supported the ethnomedical claim of essential oil as a demulcent, antidiarrheal and antioxidant drug.