Subchronic toxicity evaluation of aloesin

► Aloesin, a chromone, is a component of Aloe ferox, and may have potential for use as a medical food. ► Aloesin was tested for subchronic toxicity in Sprague-Dawley rats at doses of 250, 500, 1000mg/kg bw/day. ► Urinary ketones increased due to the ketone functionality present in aloesin, not due to a systemic effect. ► NOAEL was considered to be 1000mg/kg bw/day, the highest dose tested. Aloesin, an aromatic chromone present in various Aloe species, shows potential beneficial effects on indices related to pre-diabetic states, including metabolic syndrome. Aloesin may have utility as a functional food ingredient. As part of a program to assess its safety, aloesin was administered by oral gavage at doses of 250, 500, and 1000mg/kg body weight/day to groups of 10 male and 10 female Sprague-Dawley rats for 90days. Treatment was not associated with mortality and appeared to be well tolerated. There were no toxicologically or statistically significant changes in body weight gain or in feed and water consumption. A few statistically significant changes in serum biochemistry and hematology parameters were noted, but all were mild in nature, were confined to one sex, and/or did not show dose–response relationships. Urinalysis revealed dose-dependent increases in urinary ketones. This result was due to the presence of aloesin, which possesses ketone functionalities, in the urine and not due to a systemic effect. There was no effect of treatment on organ weights or on the results of the histopathological examinations. The no-observed-adverse-effect level was considered to be 1000mg/kg body weight/day, the highest dose tested. The results support potential use of aloesin as a functional food ingredient.