P coumaric acid

Foxtail millet husk (dry) was acquired from Jinsu Agricultural Technology Corporation (Henan Province, China). The sample was smashed (RS-FS1401 mill, Royalstar Co., Ltd., Hefei, China) sieved (40-mesh), and then stored at −20 °C.
Betaine and L-lactic acid were obtained from Shanghai Macklin Biochemical Co., Ltd., (Shanghai, China). Acetylcholinesterase, α-glucosidase (from Saccharomyces cerevisiae), and standards (vanillic acid, p-hydroxybenzoic acid, p-hydroxybenzaldehyde, caffeic acid, p-coumaric acid, ferulic acid, syringic acid, rutin, and kaempferol, the purity above 98%) were sourced from Shanghai Yuanye Biotechnology Co., Ltd., (Shanghai, China), while ABTS(2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate)), DPPH(2,2′-diphenyl-1-picrylhydrazyl), Folin–Ciocâlteu reagent, Trolox (6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid), and TPTZ(2,4,6-tris(2-pyridyl)-s-triazine) were acquired from Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). Chromatographic methanol and formic acid were purchased from Thermo Fisher Scientific Reagent Co., Ltd., (Waltham, MA, USA). All other reagents, including glycerol, sodium carbonate (Na₂CO₃), sodium acetate, sodium hydroxide (NaOH), sodium nitrite (NaNO₂), glycol, aluminum trichloride (AlCl₃), ferric chloride (FeCl₃), and methanol, were purchased from Tianjin Deen Chemical Reagent Co., Ltd. (Tianjing, China).

Two kinds of K. coccinea fruit (Zihe and Dahong in Figure 1) were collected from Tongdao County, Hunan Province, (26°54′ N, 109°42′ E), China. The scientific identification was performed by Zhonghai Li (College of Food Science and Engineer, Central South University of Forestry and Technology, Changsha, China). HUVECs were purchased from the Institute of Cell Resource Center, Chinese Academy of Science (Shanghai, China), the cell line originated from ATCC (American Type Culture Collection, Manassas, VA, USA). Cyanidin-3-glucoside, protocatechuic acid, p-hydroxybenzoic acid, cinnamic acid, syringic acid andvitexin, were purchased from Sichuan Victory Biological Technology Co., Ltd. (Chengdu, China). Ferulic acid, p-coumaric acid, vanillic acid, hyperoside and rutin were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China). Fetal bovine serum was purchased from Bioind (Kibbutz Beit Haemek, 25115, Israel). Dulbecco’s modified Eagle’s medium (DMEM), penicillin, streptomycin and trypsin were purchased from Gibco BRL (Grand Island, NY, USA). Cytotoxicity and the proliferation assay kit was purchased from PROMEGA (Madison, WI, USA). All other chemicals were analytical grade and purchased from the China National Pharmaceutical Corporation (Shanghai, China).

The chemical standards harpagide (1), harpagoside (2), ferulic acid (3), catalpol (4), aucubin (5), cinnamic acid (6) , and caffeic acid (7) were purchased from the Chinese National Institute of Control of Pharmaceutical and Biologiceal Products (Beijing, China); angoroside C (8) was purchased from Chengdu Chroma-Biotechnology Co., Ltd. (Chengdu, China); verbascoside (9) was purchased from Shanghai Yongye-Biotechnology Co., Ltd. (Shanghai, China); p-Coumaric acid (10) and p-methoxycinnamic acid (11) were purchased from Shanghai Yuanye-Biotechnology Co., Ltd. (Shanghai, China); fumaric acid (12) was purchased from Sinopharm chemical reagent Co., Ltd. (Nanjing, China). The purity of all chemical standards is greater than 99% (Figure 2). Methanol and acetonitrile of HPLC grade were purchased from Merck (Damstadt, Germany). Ultrapure water was prepared using a Milli-Q purifying system (Millipore, Bedford, MA, USA) under a resistivity of 18.2 MΩ/cm, other reagent solutions were analytical grade (Sinopharm Chemical Reagent Co., Ltd., Shanghai, China).

The organic acid standards (L-tartaric acid, lactic acid, malic acid, acetic acid, etc.), as well as polyphenol standards (protocatechuic acid, p-hydroxybenzonic acid, chlorogenic acid, vanillic acid, (-)-epigallocatechin gallate, epicatechin, vanillin, p-coumaric acid, (-)-epicatechin gallate, isoferulic acid, etc.), were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China). Water was purified using a Milli-Q system from Millipore (Bedford, MA, USA).
Isoamyl ethanoate, benzylcarbinyl acetate, isobutyl acetate, butyl acetate, propyl acetate, hexyl acetate β-damascenone, naphthalene, cinnamene, linalool, citronellol, d-limonene, α-terpineol, nerol oxide, ethyl dodecylate, ethyl heptoate, ethyl caproate, ethyl butanoate, ethyl caprylate, ethyl propanoate, ethyl isobutyrate, ethyl n-valerate, etc., were provided by Sigma-Aldrich (Shanghai, China). The internal standard of 4-methyl-1-pentanol was obtained from Tokyo Chemical Industry Co. Ltd. (Tokyo, Japan). The calculation of retention indices (RIs) was used with n-alkanes (C8-C40) purchased from Supelco (Bellefonte, PA, USA).

Gallic acid, p-hydroxybenzoic acid, ferulic acid, trans-cinnamic acid, p-coumaric acid, benzoic acid, ellagic acid, protocatechuic acid, sinapic acid, caffeic acid, quercetin, rutin, taxifolin, isoquercitrin, catechin, gallocatechin, epicatechin, vitexin, genistin, daidzin, phloroglucinol, quinic acid, and 3,4-dihdyroxyphenylaceticacid were obtained from Yuanye Bio-Technology Co., Ltd. (Shanghai, China). Procyanidin B1, procyanidin B2, and kaempferol-3-O-rutinoside were obtained from Chengdu Pusi Biotechnology Co., Ltd. (Chengdu, China). 2,20-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,4,6tri(pyridin-2-yl)-1,3,5-triazine (TPTZ), (±)-6-Hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), fluorescein, 3′,6′-dihydroxyspiro [isobenzofuran-1 (3 H),9′-(9 H) xanthene]-3-one (FL), 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH), and EDTA-2Na were purchased from Aladdin Biochemical Technology Co., Ltd. (Shanghai, China). Thermo Fisher Scientific (Waltham, MA, USA) provided the methanol (HPLC quality), formic acid (99.9%, LC-MS grade), and acetonitrile (LC-MS grade). Cellulase (T richoderma Vride G, 400 u/mg), hemicellulase (Aspergillus niger, 20 u/mg), and pectinase (Aspergillus niger, 500 u/mg) were obtained from Yuanye Bio-Technology Co., Ltd. (Shanghai, China).

Standards of kaempferol, myricetin, chlorogenic acid, caffeic acid, p-coumaric acid, resveratrol, luteolin, gallic acid, and ellagic acid were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China). The purity of all standards was required to be greater than or equal to 98%. Potassium oxonate, xanthine oxidase and 2,6-dihydroxypurine were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China). Xanthine sodium salt (XSS) and allopurinol (APL) were purchased from Sigma Aldrich Inc. (St. Louis, MO, USA). A uric acid (UA) test kit, xanthine oxidase (XOD) assay kit (Colorimetric method), urea assay kit (BUN), and creatinine (Cr) assay kit (sarcosine oxidase) were purchased from Nanjing Jiancheng Bioengineering Institute (Nanjing, China).