Low-molecular-weight hyaluronic acid prepared through photoelectric-Fenton reaction protects Caco-2 cells from oxidative damage by regulating metabolites

Abstract

Hyaluronic acid (HA), which has been extensively used in medicine, cosmetics and food, possesses numerous bioactivities varying with its molecular weight. In the present study, a photoelectric-Fenton depolymerization method was established to prepare low-molecular-weight HA whose antioxidant activity was evaluated in Caco-2 cells through metabonomics analysis. The depolymerization products were monitored by high-performance gel permeation chromatography, thin-layer chromatography, infrared spectra, and nuclear magnetic resonance, and the results suggest 8 mM Fe²⁺ and 0.5% H₂O₂ as the optimal conditions with which 2 low-molecular-weight HA samples, DHA1 and DHA2 with relative molecular weights of 6.7 kDa and 1.6 kDa were obtained after 10 min and 25 min, respectively, in the photoelectric-Fenton system. Moreover, a comparison of HA and its depolymerization products showed minimal disruption of HA's structural units by photoelectric-Fenton reaction. In addition, metabolite analysis by LC-MS/MS revealed that both HA and DHA2 could alleviate cellular oxidative damage through modulating the arginine and proline metabolic pathways by upregulating the content of hydroxyproline and downregulating the levels of L-proline, creatinine, spermidine, L-glutamic acid, and acetyl-CoA. Notably, DHA2 exhibited superior effects compared to original HA. The study indicate that the photoelectric-Fenton degradation process holds great potential to prepare low-molecular-weight HA which possessed better protective capability against oxidative damage.