Protective Effect of Alpinia oxyphylla Fruit against tert-Butyl Hydroperoxide-Induced Toxicity in HepG2 Cells via Nrf2 Activation and Free Radical Scavenging and Its Active Molecules

Abstract

Alpinia oxyphylla Miq. (Zingiberaceae) extract exerts protective activity against tert-butyl hydroperoxide-induced toxicity in HepG2 cells, and the antioxidant response element (ARE) luciferase activity increased 6-fold at 30 μg/mL in HepG2 cells transiently transfected with ARE-luciferase. To identify active molecules, activity-guided isolation of the crude extract led to four sesquiterpenes (1, 2, 5, 6) and two diarylheptanoids (3 and 4) from an n-hexane extract and six sesquiterpenes (7–12) from an ethyl acetate extract. Chemical structures were elucidated by one-dimensional, two-dimensional nuclear magnetic resonance (1D-, 2D-NMR), and mass (MS) spectral data. Among the isolated compounds, eudesma-3,11-dien-2-one (2) promoted the nuclear accumulation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and increased the promoter property of the ARE. Diarylheptanoids, yakuchinone A (3), and 5′-hydroxyl-yakuchinone A (4) showed radical scavenging activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assays. Furthermore, optimization of extraction solvents (ratios of water and ethanol) was performed by comparison of contents of active compounds, ARE-inducing activity, radical scavenging activity, and HepG2 cell protective activity. As a result, 75% ethanol was the best solvent for the extraction of A. oxyphylla fruit. This study demonstrated that A. oxyphylla exerted antioxidant effects via the Nrf2/HO-1 (heme oxygenase-1) pathway and radical scavenging along with active markers eudesma-3,11-dien-2-one (2) and yakuchinone A (3).

Identification of mulberry leaf flavonoids and evaluating their protective effects on H2O2-induced oxidative damage in equine skeletal muscle satellite cells

“…Currently, utilizing active ingredients from traditional Chinese medicine in developing functional equine health products is a prominent trend. H 2 O 2 -induced oxidative stress serves as the primary model for assessing the biological and antioxidant effects of natural products (Zhao et al, 2011;Park et al, 2022). H 2 O 2 directly damages DNA, lipids, and other macromolecules, thereby propagating oxidative damage within cells and leading to cell death (Alía et al, 2005).…”

Hydroxyhydroquinone and Quassinoids as Promising Compounds with Hypoglycemic Activity through Redox Balance

“…Free radical intermediates generated by t-BHP can subsequently lead to oxidative stress-induced hepatocyte damage. Therefore, t-BHP has often been used to cause oxidative stress injury to in vitro cells, in order to identify antioxidant molecules from natural products [28]. Glucose uptake concentration after treatment of HepG2/IRM cells with different extracts exposed for 24 h compared to untreated HepG2/IRM cells.…”

“…Free radical intermediates generated by t-BHP can subsequently lead to oxidative stressinduced hepatocyte damage. Therefore, t-BHP has often been used to cause oxidative stress injury to in vitro cells, in order to identify antioxidant molecules from natural products [28].…”

Hydroxyhydroquinone and Quassinoids as Promising Compounds with Hypoglycemic Activity through Redox Balance

“…Free radical intermediates generated by t-BHP can subsequently lead to oxidative-induced hepatocyte damage. Therefore, t-BHP has often been used to cause oxidative stress injury to in vitro cells, in order to identify antioxidant molecules from natural products [28].…”