28 Days repeated oral dose toxicity test of aqueous extracts of mahwangyounpae-tang, a polyherbal formula.

Mahwangyounpae-tang (MT), consisting of 22 types of herbal extracts has been used for thousands of years in Korean traditional medicine for the oral treatment of respiratory diseases including asthma. As part of a safety evaluation of MT extract for use in asthma, the 28 day repeat oral dose toxicity of an aqueous MT extract was evaluated at 800, 400 and 200mg/kg per day dose levels. The results showed that no significant toxicological changes were observed when 200 and 400mg/kg per day of MT extract was administered to rats. But when the dose was increased to 800 mg/kg per day, increases of body weights, food consumptions, and heart and kidney weights were observed with hypertrophy of heart and tubular necrosis of kidney. Besides this, no other signs of toxicity were observed. Based on these results, it can be concluded that the no observed adverse effect level of MT extract is 400mg/kg per day. Therefore, the use of MT is expected to be safe because 30 mg/kg was shown to be pharmacologically effective in mice and the high dose heart and kidney findings are not considered to represent any safety concern for humans.