Optimization of the extraction of polyphenols and antioxidant capacities from two types of Solanum gilo Raddi using response surface methodology

Solanum gilo Radii is traditionally used in cooking by the local people of Brazil. The aim this work was to investigate the influence of extraction methods, ethanolic degree, and extraction time on of total phenolic compounds (TPC), flavonoids, and the antioxidant potential of immature fruits of two types of S. gilo, Long Light Green (LLG) and Spherical Dark Green (SDG), using response surface methodology (RSM). The dried and pulverized immature fruits were submitted to turbo-extraction, dynamic maceration, and sonication with different ethanolic degree (96, 70, and 40 %) and extraction times (10, 20, and 30 min). The experimental design approach using RSM was successfully applied for predicting dry residue, phenolics and flavonoids contents and antioxidant activities from the dry fruits of two types of S. gilo. The results showed that the most important variable in the extraction procedure was the ethanolic degree and the most promise type of S. gilo was SDG. The best ethanol degree was 61 % for TPC, 79 % TFF, 59 % TAC, and 65 % DPPH. These results demonstrate the potential benefit of S. gilo as an important dietary source of phenolic antioxidants for human health.