Reduced glutathione

¹H NMR, ¹³C NMR, and DEPT spectra were recorded at 500 MHz for ¹H and at 125 MHz for ¹³C, with a Bruker DRX 500 instrument in DMSO-d₆ solution. ESI-MS spectra were recorded on a Bruker Esquire 3000^plus mass spectrometer, using a negative ion probe with samples dissolved in methanol.
1,1-Diphenyl-2-picrylhydrazyl (DPPH), ferrozine, and Folin-Ciocalteu reagent were purchased from Sigma Aldrich Co (St. Louis, MO, USA). The reference standard Pycnogenol (Maritime Pine Extract, containing 673 mg proanthocyanidins per g material) was purchased from the United States Pharmacopeial Convention (Rockville, MD, USA). The reference standards gallic acid (purity ≥ 98%), rutin (purity ≥ 98%), proanthocyanidins (purity ≥ 95%), and ascorbic acid (purity ≥ 99%) were purchased from Internet Aladdin reagent database Inc. (Shanghai, China). The detection kits for protein content, total antioxidative capacity (T-AOC), superoxide anion free radical, hydroxyl free radical and malondialdehyde (MDA), aspartate aminotransferase (AST), alanine aminotransferase (ALT), superoxide dismutase (SOD), and reduced glutathione (GSH) were purchased from Nanjing Jiancheng Bioengineering Institute (Nanjing, Jiangsu, China). All other reagents were of analytical grade and made in China.

DDC (D154604) was obtained from Aladdin (Shanghai, China). Biochemical kits, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), reduced glutathione (GSH), MDA, SOD, and catalase (CAT) were supplied by Nanjing Jiancheng Bioengineering Institute (Nanjing, China). Enzyme-linked immunosorbent assay (ELISA) detection kits, including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β), were obtained from Multi Sciences Biotech Company (Hangzhou, China). All phenolic standards were purchased from Must bio-technology CO., Ltd. (Chengdu, Sichuan, China) with purity ≥ 97%.