Fermentation of Chenopodium formosanum Leaf Extract with Aspergillus oryzae Significantly Enhanced Its Physiological Activities

Chenopodium formosanum Koidz (CF) is an indigenous cereal plant of Taiwan. Its high content of secondary metabolites and nutrients has attracted attention for its use in skin care products and functional foods. However, most studies have focused on the extract of CF seeds, which are relatively expensive, and none have investigated the effects of combining extraction and fermentation. In this study, we evaluated the utility of using extracts of different parts of CF, i.e., the leaves, stems, and unhulled and hulled seeds. We first made aqueous, ethanolic, methanolic, and ethyl acetate extracts of the four parts. After assessing their biological activities, we selected only unfermented and fermented CF leaf methanolic extracts for subsequent analysis. None of the concentrations of fermented CF leaf extract (≤400 mg/L) were cytotoxic, and all exhibited antioxidative, anti-inflammatory, antimicrobial, skin-whitening, moisturizing, and antiaging activities. The concentrations of protocatechuic acid, epicatechin, gallic acid, and quercetin increased the most after fermentation. Therefore, they were subjected to a molecular docking analysis, which revealed that quercetin and epicatechin may contribute the most to skin-whitening and antiaging properties, respectively. In conclusion, fermented CF leaf methanolic extracts can be useful as a functional ingredient in health foods, botanical drugs, and cosmetic products.