Acute and Subchronic Toxicity Study of Flavonoid Rich Extract of Glycyrrhiza glabra (GutGard®) in Sprague Dawley Rats

Glycyrrhiza glabra (G. glabra) is well known for its health benefits based on the traditional and current scientific evidence. The aim of the present study was to evaluate the safety of GutGard, a standardised-flavonoid rich extract of G. glabra. The study was designed to evaluate the acute and subchronic oral toxicity of GutGard in Sprague Dawley rats according to the procedures and methods of Organisation for Economic Cooperation and Development (OECD) test guidelines for acute and subchronic toxicity. A single dose of GutGard at 5000 mg/kg body weight did not produce treatment related clinical signs of toxicity or mortality in any of the animals tested during the 14-day observation period. Therefore, the median lethal dose was estimated to be more than 5000 mg/kg. A subchronic oral toxicity study for 90 days in rats at the dose levels of 250, 500, and 1000 mg/kg did not show any treatment related adverse clinical signs. The treated animals exhibited normal weight gain and comparable feed intake. Ophthalmoscope examination did not reveal any abnormalities. Further, GutGard administration in rats did not show any clinical evidence of toxicity with respect to urinalysis, haematology, and blood chemistry parameters. The relative organ weight of vital organs did not differ significantly as compared to control. Gross and histopathological findings did not show any remarkable and treatment related changes. Based on the current experimental study findings, the median lethal dose (LD50) of GutGard was found to be >5000 mg/kg b.wt and the no observed adverse effect level (NOAEL) was found to be 1000 mg/kg rat b.wt.