Studies of the toxicological potential of capsinoids: VII. A 13-week toxicity study of dihydrocapsiate in rats.

To evaluate the safety of dihydrocapsiate (4-hydroxy-3-methoxybenzyl 8-methylnonanoate; CAS No. 205687-03-2), a 13-week gavage toxicity study was conducted in Sprague-Dawley rats (10/sex/group). Test subjects received either dihydrocapsiate, 100, 300, or 1000 mg/kg/day, or vehicle by gavage and were observed for antemortem and postmortem signs of toxicity, which included changes in clinical signs, body weights, food consumption, water intake, ophthalmology, clinical pathology (clinical chemistry, hematology, urinalysis), tissue findings (macroscopic and microscopic examination), as well as organ weights. No changes attributable to the test article were observed in clinical signs, body weights, food consumption, water intake, ophthalmology, urinalysis, hematology, or histopathology. A number of sporadic blood chemistry differences were observed at the high dose between treated and controls, but were not of toxicological significance and were not attributable to the test article. These included increased alanine aminotransferase (ALT) activity in males; increased total protein in males and females; increased calcium, percentage of albumin fraction, and A/G (albumin/globulin) ratio and decreased percentage of gamma-globulin fraction in female rats. An effect, which was attributable to the test article, was increases in both absolute and relative liver weights in the high dose (both sexes). In the absence of histopathological changes attributable to the test article, the liver weight changes were considered adaptive (physiological) in nature and not of toxicological significance. It was concluded that the no observed adverse effect level (NOAEL) of dihydrocapsiate was 1000 mg/kg/day for both male and female rats in this 13-week gavage study.