Taxol has been widely used as an anticancer drug for ovarian, breast, lung and prostate cancer. Some kinds of Taxus plants are widely distributed in the Northeast Asia region. We have isolated seven tricyclic diterpenoids, taxinine, taxagifine, 5-O-cinnamoyltaxacin I triacetate, 5-decinnamoyltaxinine J, 5-cinnamoyl-9-acetyltaxicin I, taxacin and taxol from the needles of Taxus media var. Hicksii, and investigated their effects on stimulus-induced superoxide generation and translocation of cytosolic compounds to the cell membrane in human neutrophils. Six tricyclic diterpenoids used in this experiment suppressed the superoxide generation induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) and arachidonic acid (AA) in a concentration-dependent manner. Taxinine significantly suppressed the superoxide generation induced by phorbol 12-myristate 13-acetate (PMA). The compounds also suppressed fMLP- and AA-induced tyrosyl or PMA-induced serine/threonine phosphorylation, and translocation of cytosolic compounds, p47 (phox), p67 (phox) and Rac to the cell membrane in parallel with the suppression of the stimulus-induced superoxide generation.

In present work, the effects of bioflavonoids (ginkgetin and sciadopitysin) on stimulus-induced superoxide generation, tyrosyl and serine/threonine phosphorylation of proteins in human neutrophils, and the translocation of cytosolic compounds (p47phox, p67phox and Rac) to cell membrane were studied, which were isolated from the needles of Taxus media var. Hicksii. Meanwhile, three normal flavonoids (apigenin, quercetin and isoquercetin) were involved as contrasts. The results indicated that ginkgetin and sciadopitysin were capable of concentration-dependently inhibitory effects on the superoxide generation induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP), arachidonic acid (AA) and phorbol-12-myristate 13-acetate (PMA). And they also suppressed fMLP- and AA- induced tyrosyl or PMA-induced serine/threonine phosphorylation and the translocation of cytosolic compounds (p47phox, p67phox and Rac) to cell membrane, which were in parallel with the suppression of the stimulus-induced superoxide generation. The effect of these compounds on the radical-scavenging was also investigated. Ginkgetin and sciadopitysin did not show remarkable effect on DPPH radical-scavenging activity, and they didn’t display the radical-scavenging activity on superoxide anion generated by phenagine methoxysulfate (PMS)-NADH system. Apparently, ginkgetin and sciadopitysin had great performance in pharmacological value and they are worthy of in-depth study.