Acute and subchronic toxicological evaluation of Stachys lavandulifolia aqueous extract in Wistar rats

Stachys lavandulifolia (S. lavandulifolia) is a plant that has been widely used as an herbal medicine in Iran. Unfortunately, despite the prevalent medicinal uses of the plant, there are no reports on the possible toxic effects of S. lavandulifolia. In the present study the potential toxicity of S. lavandulifolia after acute and subchronic administration in rats was evaluated. Rats were orally treated with single doses of S. lavandulifolia aqueous extract and screened for signs of toxicity two weeks after administration. In the sub-chronic toxicity study, S. lavandulifolia was administered for 45 days. Mortality, clinical signs, body weight changes were assayed during the study. After 45 days animals were sacrificed and hematological and biochemical parameters, as well as weight of some organs were measured. All of the rats treated with different concentrations of water extracts of S. lavandulifolia were alive for all 14 days of observation. No hematological changes were observed a part from significant increase in WBC and neutrophils counts. Moreover, serum aspartate aminotransferase (AST) and creatinine significantly increased. Histopathological examinations showed fatty change, degeneration of hepatocytes and renal glomerular atrophy in the male rats. In the female rats, atrophy of hepatocytes and dilatation of sinusoids in liver, hyperemia and degeneration of renal epithelium mostly in cortical region were observed. Based on the results of this study no observed adverse effect level (NOAEL) of the total aqueous extract of S. lavandulifolia considered to be 250 and 100 mg/kg/day for the male and female rats, respectively.