Seasonal variation, chemical composition, and analgesic and antimicrobial activities of the essential oil from leaves of Tetradenia riparia
Seasonal variations of the essential oil from fresh leaves of Tetradenia riparia (1,2) cultivated in southern Brazil were analyzed by CG-MS, and the analgesic and antimicrobial activities of the oil were assayed. The yield of essential oil varied from 0.17% to 0.26%, being highest in winter and lowest in spring. The essential oil contained 14-hydroxy-9-epi-caryophyllene as the most abundant component (19.3–26.1%), followed by calyculone (12.1–25.7%), cis-muurolol-5-en-4-α-ol (7.4–14.9%), fenchone (2.6–13.4%), and α-trans-bergamotene (1.1–5.2%). Samples collected in summer were richer in oxygenated monoterpene (20.6%), whereas those in spring were higher in oxygenated sesquiterpene (69.3%), and those in winter were higher in oxygenated diterpenes (39.9%). The contents of most chemical constituents varied significantly (p<0.05) with the seasons. The essential oil exhibited good analgesic activity on acetic acid-induced writhing in mice, and this activity was not affected by seasonal variation. The antimicrobial activity of the essential oil against the bacteria Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, Klebsiella pneumonia, Proteus mirabilis, Morganella morganii, and Enterobacter cloacae, and the pathogenic fungus Candida albicans was assessed by the disc diffusion method and determination as the minimum inhibitory concentration. The results of the antimicrobial assays indicated that all the microorganisms tested were affected significantly (p<0.05) by seasonal variations in the oil.
Acknowledgements: The authors are grateful to CNPq for providing a research grant and fellowships
References: 1. Campbell, W.L. et al. (1997) Planta Medica. 63: 270–272.
2. Omolo, M.O., et al. (2004) Phytochemistry, 65: 2797–2802.