Activity Guided Isolation of Phenolic Compositions from <i>Anneslea fragrans</i> Wall. and Their Cytoprotective Effect against Hydrogen Peroxide Induced Oxidative Stress in HepG2 Cells

• Main Authors: Shuyue He, Xiaoyan Cui, Afsar Khan, Yaping Liu, Yudan Wang, Qimin Cui, Tianrui Zhao, Jianxin Cao, Guiguang Cheng
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Molecules
• Subjects: <i>Anneslea fragrans</i>; antioxidant; guided isolation; oxidative stress; flavonoid glycosides
• Online Access: https://www.mdpi.com/1420-3049/26/12/3690

<i>Anneslea fragrans</i> Wall., commonly known as “Pangpo Tea”, is traditionally used as a folk medicine and healthy tea for the treatment of liver and intestine diseases. The aim of this study was to purify the antioxidative and cytoprotective polyphenols from <i>A. fragrans</i> leaves. After fractionation with polar and nonpolar organic solvents, the fractions of aqueous ethanol extract were evaluated for their total phenolic (TPC) and flavonoid contents (TFC) and antioxidant activities (DPPH, ABTS, and FRAP assays). The <i>n</i>-butanol fraction (BF) showed the highest TPC and TFC with the strongest antioxidant activity. The bio-guided chromatography of BF led to the purification of six flavonoids (<b>1</b>–<b>6</b>) and one benzoquinolethanoid (<b>7</b>). The structures of these compounds were determined by NMR and MS techniques. Compound <b>6</b> had the strongest antioxidant capacity, which was followed by <b>5</b> and <b>2</b>. The protective effect of the isolated compounds on hydrogen peroxide (H₂O₂)-induced oxidative stress in HepG2 cells revealed that the compounds <b>5</b> and <b>6</b> exhibited better protective effects by inhibiting ROS productions, having no significant difference with vitamin C (<i>p</i> > 0.05), whereas <b>6</b> showed the best anti-apoptosis activity. The results suggest that <i>A. fragrans</i> could serve as a valuable antioxidant phytochemical source for developing functional food and health nutraceutical products.