Enrichment of polyphenols from Cinnamomum camphora seed kernel by macroporous adsorption resins and evaluation of its antioxidant and enzyme inhibitory activities

Abstract

The Cinnamomum camphora seed kernel (CCSK) has potential as a natural source of bioactive phenolics. However, there is limited information on the recovery and characteristics of polyphenols from the by-product of CCSK after oil extraction. In this study, an efficient macroporous adsorption resin technology was established to enrich polyphenols from CCSK (CCSK-P). HJ-18 resin was found as the most appropriate adsorbent because of its highest adsorption/desorption capacity for CCSK-P. The pseudo-second-order kinetic and Freundlich isotherm models better described the whole adsorption process. The adsorption process was spontaneous, physical, and dominated by multilinear intraparticle diffusion. The optimum enrichment procedure of CCSK-P on HJ-18 resin was as follows: for adsorption, loading flow rate and sample volume were 1.5 BV/h, and 4.79 BV, respectively; for desorption, the eluent type, elution flow rate and volume were 80% ethanol, 3.0 BV/h and 8 BV, respectively. After one-step large-scale enrichment, the total polyphenol content of CCSK-P was increased 7.11-fold with a recovery of 81.07%. Moreover, enriched CCSK-P showed significantly higher scavenging ability against DPPH radical and ABTS radical and higher inhibitory activity against α-amylase and α-glucosidase. In conclusion, CCSK-P was well enriched by HJ-18 resin and exhibited good antioxidant and enzyme inhibition activity, which may be applied in the food, cosmetic and pharmacy industries. This study provides a meaningful guidance for the industrial enrichment of polyphenols from CCSK.