Efficacy of Green Extracting Solvents on Antioxidant, Xanthine Oxidase, and Plant Inhibitory Potentials of Solid-Based Residues (SBRs) of Cordyceps militaris

Abstract

Solid-based residues (SBRs) of Cordyceps militaris are often considered as waste after the cultivation of the fruiting body. To demonstrate the value of this by-product, different ratios of two favorable green solvents (EtOH and water) were employed to optimize the yields of cordycepin (Cor) and adenosine (Ado) and investigate relevant activities of plant growth inhibition (allelopathy), antioxidants, and xanthine oxidase. The SBR extracts of 60% EtOH-40% water (W4) and 40% EtOH-60% water (W6) exhibited the highest antioxidant activity as well as yielded the optimum content of Cor and Ado. The W4 and Wt (hot water) exhibited maximum inhibitory effects on the growth of Raphanus sativus (radish), Lactuca sativa (lettuce) and two noxious weeds, Echinochloa crus-galli (barnyard grass) and Bidens pilosa (beggarticks). Furthermore, GC-MS scan analysis revealed the presence of 14 major compounds in the SBRs. W4 is the best solvent to optimize yields of Cor and Ado, as well as having the strongest levels of antioxidant activity, xanthine oxidase, and growth-inhibitory activity. This study reveals that SBRs are a potential source of medicinal and agricultural utilization.