The Inhibitory Action on Rabbit Platelet Aggregation by Vitisin C from Vitis thunbergii

• Main Authors: Pei-Shan Tsai, 蔡佩姍
• Other Authors: Jyh-Fei Liao
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/56573587426053438423

碩士 === 國立陽明大學 === 藥理學研究所 === 94 === Vitis thunbergii Sieb. & Zucc. has been used as a remedy for diarrhea, hepatitis, and injury in Taiwan. Resveratrol, a polyphenolic compound found naturally in grapes and red wine, exhibits broad biological activities such as anti-inflammatory, anticancer, anti-oxidative, antifungal, and anti-platelet properties. Five resveratrol derivatives, vitisinols B to D, viniferal, and vitisin C, were isolated from the roots of V. thunbergii and their effects on rabbit platelet aggregation were characterized in vitro in the present study. The results showed that vitisin C was the most potent compound to suppress platelet aggregation induced by arachidonic acid (AA, 100 μM) with the IC50 value of 16.62 ± 0.15 μM. Vitisin C did not affect the production of AA metabolites, thromboxane A2 (TXA2) and malondialdehyde, during platelet activation by AA. However, vitisin C suppressed U46619 (a TXA2 analogue, 1 μM)-induced platelet aggregation with the IC50 value of 9.20 ± 2.01 μM. Furthermore, radioligand receptor binding assay showed that vitisin C could compete with [3H]SQ29548 (a prostanoid TP receptor antagonist) binding to TP receptors on rabbit platelets with the Ki value of 16.7 ± 0.4 μM. Vitisin C also suppressed U46619-induced increase in platelet IP3 and [Ca2+]i levels but had no effects on cAMP and cGMP levels. In addition, it could decrease PKC translocating from the cytosol to membrane of platelet under U46619 stimulation. Therefore, the present study demonstrated for the first time that vitisin C may block the TP receptor to inhibit the down-stream signal transduction and platelet aggregation induced by AA or U46619.