Effects of Solid-State Fermentation Using R. Oligosporus on the Phytochemical Composition of Wild-Simulated Ginseng Leaf and Its Biological Properties

Wild-simulated ginseng (WSG) harvested from mountainous terrains without specialized facilities is commonly utilized as a functional food in Asian nations due to its abundance of bioactive compounds like ginsenosides. However, the protracted cultivation period, diminished survival rate, and limited size of WSG curtail its application in the food sector. This investigation assessed the fermentation of WSG leaves, which are annually harvestable, employing Rhizopus oligosporus over a span of 10 days. The study observed an augmentation in the phytochemical constituents of fermented WSG leaves, inclusive of squalene, phenols, saponins, and a majority of ginsenosides, except Rb1. Remarkably, L-carnitine was newly formed in the WSG leaves, attaining a concentration of 165.1 μg/g post 10 days of fermentation. Additionally, minor ginsenosides Rg2, Rg3, Rh1, F1, F2, and CK demonstrated a 1.32 to 4.43 fold enhancement compared to their unfermented counterparts. Optimal antioxidant activities, gauged by FRAP and ORAC assays, were realized after three days of fermentation. Moreover, fermented WSG leaves exhibited superior inhibition of nitric oxide (NO) release in lipopolysaccharide (LPS)-induced RAW264.7 cells and lipid accumulation in mouse 3T3-L1 cells compared to non-fermented leaves. Consequently, these findings imply that fermented WSG leaves may hold promising applications as functional ingredients within the food industry.