eCAM Advance Access published online on May 19, 2009
eCAM, doi:10.1093/ecam/nep041
Health-Beneficial Phenolic Aldehyde in Antigonon leptopus Tea
1Bioactive Natural Products and Phytoceuticals, Department of Horticulture and National Food Safety and Toxicology Center, Michigan State University, East Lansing, MI, USA, 2Department of Basic Medical Sciences, The University of the West Indies, Mona, Kingston, Jamaica and 3Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
Tea prepared from the aerial parts of Antigonon leptopus is used as a remedy for cold and pain relief in many countries. In this study, A. leptopus tea, prepared from the dried aerial parts, was evaluated for lipid peroxidation (LPO) and cyclooxygenase (COX-1 and COX-2) enzyme inhibitory activities. The tea as a dried extract inhibited LPO, COX-1 and COX-2 enzymes by 78%, 38% and 89%, respectively, at 100 µg/ml. Bioassay-guided fractionation of the extract yielded a selective COX-2 enzyme inhibitory phenolic aldehyde, 2,3,4-trihydroxy benzaldehyde. Also, it showed LPO inhibitory activity by 68.3% at 6.25 µg/ml. Therefore, we have studied other hydroxy benzaldehydes and their methoxy analogs for LPO, COX-1 and COX-2 enzymes inhibitory activities and found that compound 1 gave the highest COX-2 enzyme inhibitory activity as indicated by a 50% inhibitory concentration (IC50) at 9.7 µg/ml. The analogs showed only marginal LPO activity at 6.25 µg/ml. The hydroxy analogs 6, 7 and 9 showed 55%, 61% and 43% of COX-2 inhibition at 100 µg/ml. However, hydroxy benzaldehydes 3 and 12 showed selective COX-1 inhibition while compounds 4 and 10 gave little or no COX-2 enzyme inhibition at 100 µg/ml. At the same concentration, compounds 14, 21 and 22 inhibited COX-1 by 83, 85 and 70%, respectively. Similarly, compounds 18, 19 and 23 inhibited COX-2 by 68%, 72% and 70%, at 100 µg/ml. This is the first report on the isolation of compound 1 from A. leptopus tea with selective COX-2 enzyme and LPO inhibitory activities.
Keywords: anti-inflammatory – cyclooxygenase enzyme – lipid peroxidation – tea – traditional medicine
For reprints and all correspondence: Muraleedharan G. Nair, Bioactive Natural Products and Phytoceuticals, 173 National Food Safety and Toxicology Center, Michigan State University, East Lansing, MI, USA. Tel: +1-517 884 2018; Fax: +1-517-432-2310; E-mail: nairm{at}msu.edu
Received December 2, 2008; accepted April 23, 2009