Efficient purification of flavonoids from bamboo shoot residues of Phyllostachys edulis by macroporous resin and their hypoglycemic activity

Abstract

The adsorption/desorption process of flavonoids obtained from bamboo shoots residues of <i>Phyllostachys edulis</i> (RPEFs) was established by resin screening, adsorption isotherms, adsorption kinetics and dynamic tests. Results indicated the Langmuir equation fairly fitted the isotherms data and the pseudo-second-order model accurately described its kinetic adsorption on HPD-500 resin. The optimal process was as follows: 2 mg/mL of solution, 2.8 BV feed volume under 2 BV/h flow rate for adsorption; 5 BV volume of 70 % ethanol with a flow rate of 2 BV/h for desorption. After enrichment, the flavonoids in RPEFs increased from 1.39 % to 37.34 %. The analysis of UPLC-TOF-MS/MS uncovered that the purified RPEFs were composed of four major flavonoids. It had potent hypoglycemic activity <i>via</i> PI3K/AKT pathway by upregulating the protein expression of PI3K, AKT, IRS-1, and GLUT4 in a dose-dependent manner based on HepG2-IR cells. Those results provide possible utilization of <i>Phyllostachys edulis</i> by-products in food additives.