Toxicological evaluation of the dried hydroethanolic extract of Amaranthus spinosus L. roots in Artemia salina larvae and Sprague Dawley rats

Abstract Background Amaranthus spinosus is a medicinal plant used in traditional medicine to treat several diseases including diabetes and its complications. The aim of this study was to prove the safety of the plant in animal health. Methods The dry extract was obtained following the hydroethanolic extraction of A. spinosus roots. The cytotoxicity was evaluated in vitro by incubating Artemia salina larvae with the extract for 24 h. In vivo toxicity was assessed in Sprague Dawley rats. A single dose of 5000 mg/kg bw of extract was administered orally to female rats in acute toxicity and observed for 14 days for mortality and signs of toxicity. In subchronic toxicity, extract doses of 500 and 1000 mg/kg bw were administered orally to male and female rats for 28 consecutive days and observed for previous signs. Body weight was recorded daily and blood glucose levels every week. On day 29, blood was collected for biochemical and hematological studies. Organs were then exised for gross autopsy and histopathological examination. Results The in vitro study showed that the extract had a LC50 = 1.178 mg/mL in larvae and was considered to be non-cytotoxic. Oral administration of extract at a single dose of 5000 mg/kg bw did not cause any mortality or sign of toxicity in gross necropsy. In subchronic oral toxicity, repeated doses of 500 and 1000 mg/kg bw of extract, did not also cause any mortality or significant change in body weight, relative weight of vital organs. Furthermore, hematological and biochemical parameters and histopathological examination did not show any significant change. The observed decrease in blood glucose levels did not correlate with organ damage and supports the safety of the plant. However, the reduction of LDL-cholesterol has shown that the extract can prevent cardiovascular disease. Conclusions This finding demonstrated that A. spinosus root is non-toxic with a LD50 > 5000 mg/kg bw. Thus, the extract can be used for cutaneous and subchronic oral administration at doses ≤ 1000 mg/kg bw. However, further studies such as embryo/fetotoxicity, genotoxicity and neurotoxicity will be needed to prove the safety of chronic administration of the extract in patients and fetuses.