| Abstract |
In the last decade, green chemistry has been attracting great interest in many contexts, including, among others, natural antioxidants. However, only a few works deal with natural residue extracts and biowaste, which could be an efficient, economical and environmentally friendly source for the production of useful compounds. In this study, we look for antioxidant activity in Araucaria araucana seeds, an iconic pine species of the Argentine and Chilean Patagonia commonly known as "pehuen". Pinones are the edible pehuen seeds, and it is estimated that approximately 40 tons of pinones are harvested annually in Argentina and Chile. The chemical composition, antioxidants, metal corrosion-inhibiting properties and biological activity of edible and discarded pinon tissues were determined. Acute toxicity was discarded by in vitro testing and double fluorescent staining. Biological activity was evaluated in vivo by determining redox markers in salivary glands from rats treated with Cyclophosphamide (an oncological drug). All pinon tissues had antioxidants and antioxidant activity, with the coats showing the highest levels (up to 404 mu g ascorbic acid equivalent per mg). The coats, in particular, had high gallic acid, catechin, quercetin and tannin contents, and more antioxidant activity, polyphenols and flavonoids than berries from the region. Results by X-ray fluorescence spectrometry showed that Na, Mg, P, S, Cl, K, and Ca were majority elements in the coat, embryo and endosperm. Furthermore, coat extract also showed significant anti-corrosion activity and in vivo protection against oxidative damage. The results indicate that pinon biowaste is a low-cost attractive source of natural antioxidants with potential nutraceutical, medical and metal corrosion protection applications. |