Effects of a 2-week diet of Pycnogenol and Grape Seed Extract on the Cardiovascular Function of Rats

Kubota Yoko, Kobayashi Kyoko, Tanaka Naoko, Kagota Satomi, Nakamura Kazuki, Kunitomo Masaru, Umegaki Keizo, Shinozuka Kazumasa

doi:10.18891/jjfcs.10.3_127

In a previous study, we examined the effects of various dietary supplements on the cardiovascular function of rats. The results suggested that the feeding of ginkgo biloba extract diet increased the liver weight, enhanced gene expression of hepatic cytochrome P-450 in the liver and attenuates the hypotensive effect of nicardipine. In this study, we examined that the effects of the proanthocyanidinsrich pycnogenol and grape seed extract on the cardiovascular function of Wistar rats, which were fed ad libitum on a diet of pycnogenol and grape seed extract for 2 weeks. Furthermore, we studied the effects of pycnogenol and grape seed extract on the liver weight, because ginkgo biloba extract is known to contain proanthocyanidins. The proanthocyanidin content in pycnogenol, grape seed extract, ginkgo biloba extract, isoflavones and catechins as determined by the vanillin-HCl assay were 17.9, 25.4, 2.9, 0.7 and 16.6%, respectively. After feeding for 2 weeks, the liver, atria and aorta were isolated from rats. The diet of pycnogenol and grape seed extract did not change body weight or liver weight. Isoproterenol-induced positive and acetylcholine-induced negative inotropic and chronotropic effects on the atria were not affected by the diet, nor was acetylcholine and sodium nitroprusside-induced relaxation of the aortic rings. In in vitro experiments, pycnogenol (1.0 mg/ml) significantly increased the beat rate of the atria isolated from the rats. In addition, pycnogenol (3-300μg/ml) caused a dose-dependent relaxation in the aortic ring precontracted with noradrenaline. These results suggested that a diet of pycnogenol and grape seed extract did not change the cardiovascular function in vivo. Furthermore, proanthocyanidins in pycnogenol and grape seed extract did not increased the liver weight.

Effects of a 2-week diet of Pycnogenol and Grape Seed Extract on the Cardiovascular Function of Rats

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