Anti-Inflammatory and Antioxidant Activities of Polyphenols From Loquat (Eriobotrya japonica Lindl.) Leaf Hair in Lipopolysaccharide-Induced In Vitro and In Vivo Models

This study aimed to characterize polyphenols present in Loquat (Eriobotrya japonica Lindl.) leaf hair (LLH) and evaluate their antioxidant and anti-inflammatory effects in lipopolysaccharide (LPS)-induced inflammation models In Vitro and In Vivo. Ultra-performance liquid chromatography coupled with UPLC-HRMS identified 24 compounds in LLH, including 21 polyphenols, notably revealing the presence of four polymethoxyflavones previously unreported in loquat. Antioxidant evaluations (ABTS, DPPH, FRAP, and ORAC) confirmed robust radical-scavenging and reducing capabilities of LLH extract. In Vitro studies utilizing human liver L02 cells demonstrated that LLH significantly suppressed LPS-induced reactive oxygen species (ROS) generation, preserved antioxidant enzyme activities (CAT, SOD, and GSH-Px), and upregulated antioxidant-related genes (Nrf2, Cat, Sod1, and Gpx1). Furthermore, LLH pretreatment markedly inhibited LPS-induced nitric oxide (NO) release, inflammatory cytokine (IL-1β, IL-6, and TNF-α) production, and downregulated the Jak2–Stat3 inflammatory signaling pathway. Consistently, In Vivo experiments using an LPS-induced acute liver injury mouse model revealed that oral administration of LLH significantly reduced hepatic oxidative stress and inflammation by restoring antioxidant enzyme activities, enhancing Nrf2-mediated antioxidant pathways, and suppressing inflammatory mediators and Jak2–Stat3 signaling in liver. Collectively, these findings demonstrate LLH polyphenols' potent antioxidant and anti-inflammatory effects and suggest their potential as natural functional agents for managing inflammation-related oxidative stress.