Health-Beneficial Phenolic Aldehyde inAntigonon leptopusTea

Tea prepared from the aerial parts ofAntigonon leptopusis used as a remedy for cold and pain relief in many countries. In this study,A. leptopustea, 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 g/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 g/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 compound1gave the highest COX-2 enzyme inhibitory activity as indicated by a 50% inhibitory concentration (IC50) at 9.7 g/mL. The analogs showed only marginal LPO activity at 6.25 g/mL. The hydroxy analogs6,7and9showed 55%, 61% and 43% of COX-2 inhibition at 100 g/mL. However, hydroxy benzaldehydes3and12showed selective COX-1 inhibition while compounds4and10gave little or no COX-2 enzyme inhibition at 100 g/mL. At the same concentration, compounds14,21and22inhibited COX-1 by 83, 85 and 70%, respectively. Similarly, compounds18,19and23inhibited COX-2 by 68%, 72% and 70%, at 100 g/mL. This is the first report on the isolation of compound1fromA. leptopustea with selective COX-2 enzyme and LPO inhibitory activities.