1 1 diphenyl 2 picrylhydrazyl dpph 2 2 azino bis 3 ethylbenzothiazoline 6 sulfonic acid diammonium salt

1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) were purchased from Sigma Chemical Co. (St. Louis, MO, USA). Ferric-tripyridyltriazine (Fe³⁺-TPTZ) is purchased from Beyotime Biotechnology (Shanghai, China). Chromatographic grade analytical standards asparaginic acid, glutamic acid, asparagine, serine, glutamine, histidine, glycine, threonine, citrulline, arginine, alanine, tyrosine, cystine, valine, methionine, tryptophan, phenylalanine, isoleucine, leucine, lysine, hydroxyproline, proline, 5′-CMP, 5′-UMP, 5′-GMP, 5′-IMP, 5′-XMP, 5′-AMP, trehalose, mannitol, quininic acid, l-malic acid and fumaric acid purchased from Solarbio Science & Technology Co., Ltd. (Beijing, China). α-Amylase, α-glucosidase, 4-nitrophenyl α-d-glucopyranoside (PNPG), and soluble starch were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China). All other reagents were analytical grade and obtained from Chengdu Kelong Chemical Factory (Chengdu, China).

1,1-Diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS), butylated hydroxy anisole (BHA) tert-butyl hydroperoxide, chlorpromazine, guanosine, tryptophan, ascorbic acid, silymarin and hyperoside were obtained from Sigma-Aldrich Co., St. Louis, MO, USA. Rutin and p-nitroso dimethyl aniline (p-NDA) was from Acros Organics, Morris Plains, NJ, USA. Naphthyl ethylenediamine dihydrochloride (NEDD) was from Roch-Light Ltd., Suffolk, UK. Nitro blue tetrazolium (NBT) was from SD Fine Chemicals Ltd., Mumbai, India, and 2-deoxy-d-ribose was from Hi-Media Laboratories Pvt. Ltd., Mumbai, India. Sodium nitroprusside was from Ranbaxy Laboratories Ltd., Mohali, India. Sodium carboxy methyl cellulose (CMC), sulfanilic acid and α-tocopherol were from Merck (India) Ltd., Delhi, India. Cupric chloride, ferric chloride, ferrous ammonium sulfate and all other chemicals were of analytical or equivalent grade. All chemicals were used without further purification. The water used for the preparation of solutions was purified through a Milli-Q water purification system (Millipore, Billerica, MA, USA; Specific conductivity <0.1 μs·cm⁻¹), and the sample solutions were prepared just prior to carrying out the experiments.