Biochemical and functional properties of extracts from Cordyceps militaris residues enriched with Styphnolobium japonicum flowers

Abstract

Medicinal fungus Cordyceps militaris is widely cultivated in Vietnam, yet its solid-state cultivation residues are often discarded, representing a loss of potentially valuable bioactive compounds. In this study, the solid medium was supplemented with 50% Styphnolobium japonicum flower powder to investigate the effects of fermentation on biochemical composition and bioactivities of the fermented extracts. These extract maintained the fruiting body yield while exhibiting significantly enhanced antioxidant activity (SC₅₀ = 98 µg/mL), a 1.5-fold increase over the unfermented control. Meanwhile, the antimicrobial, anti-inflammatory, tyrosinase inhibitory, and cytotoxic activities against cell lines of the post-fermentation sample remained comparable with those of the pre-fermentation sample. Although the increase in total phenolic and total flavonoid content after fermentation was statistically insignificant, several biochemical changes were observed in the TLC and HPLC profiles of the post-fermentation sample compared with the pre-fermentation control. These results suggest that supplementing medicinal substrates with plant-derived powders can effectively enhance the functional properties of the fermented products. Furthermore, this approach provides a sustainable strategy for valorising underutilised solid residues, adding economic and environmental value to C. militaris cultivation. Overall, the study highlights the potential of integrating plant supplementation and solid-state fermentation as a practical method to produce bioactive-rich extracts, contributing to the development of functional foods, nutraceuticals, and other value-added products from medicinal fungi.