The effect of lactic acid fermentation on the phytochemical content of fig leaf extracts compared to single solvent and sequential solvents extraction

Abstract

The aim of this study was to compare the antioxidant, natural products, and polyphenolic profiles of Ficus carica L. leaf extracts obtained with a sequential solvent extraction (n-hexane, dichloromethane, ethyl acetate, and methanol), a single solvent extraction with one of three different solvents (methanol, ethanol and ethyl acetate), and a fermentation assisted extraction. Extracts were assessed by high-performance thin-layer chromatography (HPTLC) fingerprinting pattern (before and after derivatization with DPPH free radical, anisaldehyde-sulfuric acid reagent and ferric chloride) and with ATR-FTIR phytochemical profiling. The results show that sequential solvents extraction may maximise the extraction of natural products, especially polyphenolics. However, the highest antioxidant activity was achieved with a single solvent extraction with ethyl acetate. Furthermore, fermentation assisted extraction further improves extraction of antioxidants when compared to single extraction from nonfermented material. In conclusion, brining and spontaneous lactic acid fermentation of plant material is a highly desirable method for improving the functional properties of extracts due to its low cost and low energy requirements.