Isolation and identification of a bioactive compound from Japanese red pine (Pinus densiflora) tea and its antioxidative effects on vascular endothelial cells

The bioactive compound, which showed a potent nitric oxide production stimulation effect, was isolated from Japanese red pine tea and identified as (+)-catechin. Compared with (−)-epigallocatechin 3-O-gallate and (−)-catechin, (+)-catechin exhibited greater NO production promotion and protection from H₂O₂-induced oxidative stress in vascular endothelial cells. The (+)-catechin content of Japanese red pine tea was found to be higher than that of buckwheat or green tea, both of which are known to contain (+)-catechin. This study indicated that (+)-catechin could be used as a potential functional ingredient for endothelium function protection and provides a basis for the use of red pine tea in endothelium dysfunction prevention in the future.