[Effects of Codonopsis pilosulae on the synthesis of thromboxane A2 and prostacyclin]

24 angina pectoris patients were treated with Codonopsis pilosulae (CP) oral solution 20 ml (containing crude CP 20 g) thrice daily for 7 days, other 10 cases were treated by aspirin 0.5 g per day for a week as the control group. After treatment, in the CP group, the plasma level of TXB2 was obviously reduced from 156.76 +/- 11.87 pg/ml to 125.01 +/- 8.85 pg/ml (means +/- S means), the inhibitory rates was 15. 67% (P less than 0.05), and of 6-keto-PGF1 alpha (6-K) was not markedly changed (P greater than 0.05). In the aspirin group, TXB2 was also reduced significantly (P less than 0.05); 6-K was reduced more than that of CP group, the inhibitory rate was 24.33 +/- 9.40% (P less than 0.05). To reveal the mechanism of CP action on the synthesis of TXA2 and PGI2, the porcine lung microsome was used as the donor of cyclooxygenase, thromboxane synthase and prostacyclin synthase, the effects of CP on the formation of TXB2 and 6-K from arachidonic acid (AA) or endoperoxides were measured by RIA respectively. The results showed that both the levels of the formation of TXB2 from AA or endoperoxides were markedly reduced by CP in a dose-dependent (at doses of 3-300 mg/ml). The synthesis of TXB2 was distinctly inhibited alone with a dose of 100 mg/ml CP, which suggested that CP might be an inhibitor of TXB2 synthase at that dose; while at a dose of 300 mg/ml CP, the synthesis of TXB2 and 6-K were inhibited simultaneously (P less than 0.001). It showed that a larger dosage of CP, which could inhibited the synthesis of both TXA2 and PGI2, its mechanism of action needs further study.