Biological and antioxidant activity of Gunnera tinctoria (Nalca)

摘要

The endemic Chilean edible plant Gunnera tinctoria (Nalca) is highly appreciated in the south of Chile by the small farmers. Nevertheless, no background exists about his secondary metabolites. In the present study, in the leaf from G. tinctoria was investigated the content of bioactive compounds like coumaric acid, ascorbic acid and total phenols; the antioxidant capacity was evaluated by 3-ethylbenzothiazoline-6-suslfonic acid (ABTS), oxygen radical absorbance capacity (ORAC), ferric reducing antioxidant power), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods reducing sugars were measured. Finally, the biological activity was evaluated against Cladophialophora and Cryptococcus laurentii. The results suggest that the most abundant constituent in the extract were catechin (1344.97 mg/100 g dry weight) and epicatechin (1429.28 mg/100g dry weight), and was confirmed and quantified by high performance liquid chromatografy (HPLC-PDA); while the ORAC methodology showed a high antioxidant capacity (192000.0±5.91 umol Trolox Eq/100 g dry weight). On the other hand, the extract had a fungicide effect against both microorganism assayed, inhibiting the growth of Cladophialophora´s mold- and the yeast Cryptococcus laurentii. This is the first report of antioxidant capacity, bioactive compounds and biological activity of G. tinctoria, and these findings suggest that an extract prepared from the Nalca leaf may be a promising source of antioxidant and bioactive compounds and as a research object by being an antifungal and therapeutic alternative in development.