Low-molecular procyanidin rich grape seed extract exerts antihypertensive effect in males spontaneously hypertensive rats

Grapes are a good source of flavonoids, which have been previously demonstrated to exert beneficial healthy effects on cardiovascular diseases. The aims of this study were to extensively characterise a grape seed procyanidin extract (GSPE) (total phenolic content, antioxidant capacity and HPLC-MS phenolic profile) and, to assess its antihypertensive effect in spontaneously hypertensive rats (SHR) which is a model of genetically hypertensive rat analogue to the essential hypertension in humans. The hypotensive effect of GSPE was also proved in normotensive Wistar-Kyoto rats. Chromatographic analysis of the extract showed that the most abundant polyphenols are monomers and dimers, in their free forms and linked to a gallate. GSPE produced a significant decrease in systolic and diastolic blood pressure of SHR dose-dependently up to 375 mg/kg (maximum decrease 6 h post-administration) and did not affect blood pressure of Wistar-Kyoto rats. GSPE increased the activity of an antioxidant endogen system, but did not affect plasma ACE activity in these animals.

► GSPE decreases SBP and DBP on hypertensive rats, but not in normotensive rats. ► Maximum decrease of SBP at 6 h post-administration of 375 mg/kg GSPE. ► GSPE increases activity of reduced glutathione, an endogenous antioxidant system. ► GSPE is rich in monomers, dimers and trimers in free form or linked to gallate. ► ACE activity and malondialdehyde, biomarker of oxidative stress, was not modified.