Antioxidation and inhibition of α-glucosidase activity of secondary metabolites of Monascus purpureus Mp-21

Abstract:

[Objective] To study the separation, purification and biological activity of secondary metabolites from Monascus purpureus Mp-21. [Methods] The secondary metabolites of Monascus purpureus Mp-21 were isolated and purified using silica gel column, RPC₁₈ column and Sephadex LH-20 gel column and other column chromatographic separation techniques, and the structure of the compound was identified by spectroscopy technique (NMR and HR-ESI-MS). The anti-oxidation and hypoglycemic-related enzyme inhibitory activities of the identified compounds were determined. [Results] Ten active compounds were identified from the secondary metabolites of Monascus purpureus Mp-21, namely FMOC-ALLO-THR(TBU)-OH (1), quercetin (2), hesperetin (3), monascin (4), monasphilone A (5), oleanolic acid (6), β-sitosterol (7), ergosterol (8)、indole-3-carboxylic acid (9) and chlorogenic acid (10). Among them, compound 1 is a new natural product, which complements the information of the compound in nature and the information of the organic spectrum. Compounds 2, 6, 9 and 10 are discovered from the Monascus for the first time. In the in vitro antioxidant activity tests of O^2-, DPPH and OH^- free radicals, compound 2 (IC₅₀ of 5.07, 4.84 and 27.39 μg/mL, respectively) showed strong antioxidant capacity. Electron paramagnetic resonance (EPR) showed that compound 2 had strong scavenging ability on DPPH and OH^-. Compound 6 had strong inhibitory activity on α-glucosidase with IC₅₀ of 22.87 μg/mL. [Conclusion] Monascus purpureus Mp-21 is a high-quality germplasm resource with high development performance, and has the potential to be developed into functional food such as antioxidant and hypoglycemic.