Isolation, X-ray crystal structure of the new diterpene and identification of others lignans and flavonoids from the fresh needles of Pinus massoniana.

Three new compounds, namely massonside C (1), massonianoside F (2), and 3, 8-dimethyl- herbacetin-7-O-β-D-glucopyranoside (3), together with five known compounds (4-8), were isolated from the fresh needles of Pinus massoniana. Their structures were established by 1D, 2D NMR, HRMS and comparison with the literature data. The absolute configuration of 1 was confirmed by a combination of X-ray single crystal analysis. All isolated compounds were evaluated for the protective effect of human umbilical vein endothelial cells against oxidative damage.