90-day oral toxicity study of a grape seed extract (IH636) in rats

To assess the safety of grape seed extract with less than 5.5% catechin monomers (IH636), 4 groups of male and female Sprague-Dawley rats were provided grape seed extract in the diet at levels of 0 (control), 0.5, 1.0, or 2.0% for a period of 90 days. All animals survived the duration of the study, and no significant changes in clinical signs, hematological parameters, organ weights, ophthalmology evaluations, or histopathological findings were observed. A significant increase in food consumption was observed in male and female rats provided the grape seed extract diets compared to that of the control rats, especially in male rats consuming 2.0% grape seed extract. This effect was not accompanied by increases in body weight gains. Grape seed extract appeared to increase the insoluble fraction of the diet. Male rats in the high-dose group exhibited decreased serum iron levels and decreased serum iron/total iron binding capacity ratio compared to those of the controls, although all values were within historical ranges for Sprague-Dawley rats. In conclusion, administration of the grape seed extract IH636 to male and female Sprague-Dawley rats in the feed at levels of 0.5, 1.0, or 2.0% for 90 days did not induce any significant toxicological effects.