Essential Oil Composition and Antibacterial Studies of Vitex negundo Linn. Extracts

Essential oils from fresh leaves, flowers and dried fruits of Vitex negundo were obtained by hydrodistillation. Using Soxhlet extractor five successive extracts from dried and powdered leaves were also taken. The chemical constituents of essential oil of leaves, flowers and dried fruits were analyzed by GC-FID and GC/MS techniques. Main constituents identified in leaves oil were delta-guaiene, carryophyllene epoxide and ethyl-hexadecenoate; in flowers oil - alpha-selinene, germacren-4-ol, carryophyllene epoxide and (E)-nerolidol while fruit oil showed beta-selinene, alpha-cedrene, germacrene D and hexadecanoic acid as the main constituents. beta-Caryophyllene was only the constituent identified as common to all three oils. alpha-Guaiene and guaia-3,7-diene were identified as common constituents in leaf and dried fruit oil while leaf and flower oils showed p -cymene, valencene, caryophyllene epoxide and (E)-nerolidol as common constituent. All the essential oils and successive extracts were evaluated for antibacterial potential against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa bacterial strains. Each of the essential oils and extracts were found to give promising results against B. subtilis and E. coli. Ethyl acetate and ethanol extracts showed prominent antibacterial activity against all the tested strains. Fruits and leaves oil were found to be most active against E. coli and S. aureus, respectively. Only flowers oil was found to be active against P. aeruginosa.