Exploration of the Functional Constituents of the Substrate of Flammulina velutipes

After harvesting, the substrate of Flammulina velutipes (SFV) is repurposed for uses such as feed, fuel, and culture medium. This study identified four phenolic acids and one flavonoid from the SFV for the first time using solvent extraction and chromatography: ferulic acid (1), ρ-coumaric acid (2), vanillic acid (3), 3-methoxygallic acid (4), and tricin (5). They showed significant activity in the DPPH scavenging test with concentrations determined by HPLC as follows: ferulic acid (218.88 mg/kg), ρ-coumaric acid (157.31 mg/kg), vanillic acid (281.54 mg/kg), 3-methoxygallic acid (33.85 mg/kg), and tricin (713.42 mg/kg). These findings indicate that the SFV is a valuable source of bioactive compounds for medicinal and health-promoting applications.