Safety assessment of aqueous extract from leaf Smallanthus sonchifolius and its main active lactone, enhydrin

Abstract

Ethnopharmacological RelevanceLeaves of Smallanthus sonchifolius (Poepp. & Endl.) H. Robinson (yacon) have been used since pre-Columbian times in the Andean region to prepare medicinal herbal tea with beneficial health properties. However, there are still disagreements about the safe use. This work was carried out to evaluate the toxicity profile of both, 10% decoction of yacon leaves and their major active lactone, enhydrin. Materials and methodsIn vitro cytotoxicity assays were performed with Hep-G2, COS1, CHO-K1 and Vero cell lines using a test of metabolic competence based upon assessment of mitochondrial performance. In vivo toxicity study was performed in adult Wistar rats. In the acute oral toxicity each group of rats was orally given a single dose of 10% decoction or enhydrin. General condition, behavior and mortality were recorded for up to 14 days post treatment. In subchronic toxicity studies, both products were given orally for 90 days to rats. Body weight and food intakes were observed weekly. Hematological, clinical chemistry parameters and organ weight were determined in all animals at the end of the experimental period. ResultsCell viability decreased in a concentration dependent fashion when cells were incubated with 2–200μg of 10% decoction and 0.015–7.5μg of enhydrin. In acute study in rats, there were no deaths or signs of toxicity observed after oral administration of single doses of 10% decoction or enhydrin at any dose level up to the highest dose tested (14.0g/kg and 0.32g/kg, respectively). In subchronic studies in rats, both products administered orally for 90 days at daily doses of 0.07, 0.14 and 0.28g 10% decoction/kg and 0.4, 0.8 and 8.0mg enhydrin/kg, did not caused haematological, biochemical and histological alterations. ConclusionsThe results presented in this paper lead us to the conclusion that the use of 10% decoction and enhydrin is safe in rat at doses in which it is demonstrated the hypoglycaemic effect.