Inhibition Effect of Cordyceps sinensis (C. sinensis) Mycelium on Some Metabolic Enzymes and Investigation of Antioxidant Properties

Cordyceps sinensis (CS), a traditional medicinal fungus, is a rich source of bioactive metabolites with pharmacological potential. This study investigated the inhibitory effects of CS mycelium on human carbonic anhydrase isoenzymes I and II (hCA I and hCA II) and acetylcholinesterase (AChE), as well as its antioxidant properties. Enzyme inhibition was assessed using spectrophotometric methods, whereas antioxidant capacity was evaluated by DPPH, ABTS, CUPRAC, FRAP, and Fe3⁺-reducing assays. LC-MS/MS analysis identified key secondary metabolites, including apigenin, apigenin-7-glucoside, (+)-taxifolin, dihydrokaempferol, p-coumaric acid, salicylic acid, and L-theanine, with apigenin as the major constituent. CS strongly inhibited hCA I (IC50 = 1.11 µg/mL) and hCA II (IC50 = 1.77 µg/mL), exceeding the potency of acetazolamide, and also showed relevant AChE inhibition (IC50 = 8.00 µg/mL), comparable to tacrine. Antioxidant assays revealed moderate DPPH activity but strong ABTS and CUPRAC reducing capacities, indicating the structural contributions of flavonoids and phenolic acids. These findings suggest that CS possess dual bioactivity through enzyme inhibition and antioxidant effects, highlighting its therapeutic potential against neurodegenerative and oxidative stress–related diseases.