Trans p coumaric acid

The phenolic standards including malvidin-3-O-glucoside, procyanidin dimers B1, gallic acid, (+)catechin, (−)epicatechin, procyanidin dimers B2, (−)-epigallocatechin, caffeic acid, myricetin, quercetin, quercetin 3-glucoside, vanillic acid, trans-p-coumaric acid, 3,4-dihydroxybenzoic acid, polydatin, kaemperol, cis-resveratrol, trans-resveratrol, trans-4-hydroxy-3-methoxycinnamic acid and viniferin were purchased from Sigma-Aldrich (St. Louis, MO, USA). The water was purified using a Milli-Q system (Millipore, Billerica, MA, USA). Ortho-phosphoric acid was obtained from Tianjin kemio chemical reagent Co., Ltd. (Tianjin, China). Acetonitrile was obtained from Fisher Scientific (Fair Lawn, NJ, USA). Acetaldehyde, DNPH-Acetaldehyde hydrazine standard, DNPH (30% water, m/m) and bovine serum albumin were obtained from Sigma-Aldrich (St. Louis, MO, USA), while the DNPH (30% water, m/m) was purified by recrystallization from Acetonitrile. All above solvents employed were high-performance liquid chromatography (HPLC grade). DPPH was purchased from Sigma-Aldrich (St. Louis, MO, USA).

Commercially available FRP CocoaVia® was purchased from Cocoavia.com (Lot number 144533, MARS International). The cocoa extract was chemically profiled for polyphenols (see below) and archived in compliance with NCCIH Product Integrity guidelines. Phenolic standards including gallic acid (GA), caffeic acid (CA), trans-p-coumaric acid (p-CA), catechin ((+)-C), epicatechin ((−)-EC), dihydrocoumaric acid (diHCA), 3-(3,4-dihydroxyphenyl)propionic acid (3,4-diHPPA), 3,4-dihydroxybenzoic acid (3,4-diHBA), hippuric acid (HA), homovanillic acid (HVA), 3-hydroxybenzoic acid (3-HBA), 4-hydroxybenzoic acid (4-HBA), 3-hydroxyphenylacetic acid (3-HPAA), 3-(3-hydroxyphenyl)propionic acid (3-HPPA), vanillic acid (VA), and trans-cinnamic acid-d₇ (internal standard) were purchased from Sigma-Aldrich (St. Louis, MO, USA); 3,4-dihydroxyphenylacetic acid (3,4-diHPAA) and ferulic acid (FA) were from ChromaDex Inc. (Irvine, CA); 5-(4-hydroxyphenyl)valeric acid (4-HPVA) was from Alfa Aesar (UK). Acids and solvents (all HPLC Grade) including glacial acetic acid (AA), formic acid (FA), acetonitrile (ACN), methanol (MeOH) and ethyl acetate were obtained from Fisher Scientific (Pittsburgh, PA, USA), and Pierce™ LC-MS water from Thermo Fisher Scientific (Waltham, MA, USA).

HPLC-grade methanol (MeOH), HPLC-grade acetonitrile (ACN), dimethyl sulfoxide (DMSO), sodium carbonate (Na₂CO₃ > 99%), aluminium chloride (AlCl₃ > 99%), D-(+)-glucose, DL-lactic acid (90%), choline chloride (98%), and standard compounds: ethyl-o-vanillin - ISTD (99%), diosmin (95%), rutin (99%), chrysin (99%), morin hydrate (95%), myricetin ( > 96%), apigenin (97%), (–)-epicatechin (99%), (+)-catechin, vanillic acid (97%), syringic acid (97%), trans-p-coumaric acid (98%), o-coumaric acid (98%), ferulic acid (98%), and rosmarinic acid (97%) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Chlorogenic acid (99%), trans-cinnamic acid (98%), quercetin hydrate (99%) and flavone (99%) were supplied by Acros Organics (Belgium). Protocatehuic acid (99%), caffeic acid (99%) and kaempferol as well as Folin–Ciocalteu phenol reagent (2N), D-(–)-fructose and sodium acetate (CH₃COONa) were supplied by Merck (Germany). Gallic acid (99%) was purchased from Carlo Erba (Italy). Ultrapure water (resistance above 18 MΩ cm) used was obtained from a Milli-Q water purification system.

All solvents and chemicals were of analytical grade. Nutrient Broth (NB), Nutrient Agar (NA), Mueller Hinton Broth (MHB), Mueller Hinton Agar (MHA), McFarland standard were purchased from Oxoid (Basingstone, UK). 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH), 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA), dinitrophenylhydrazine (DNPH), trichloroacetic acid (TCA), perchloric acid (PCA), thiobarbituric acid (TBA), 1,1,3,3-tetramethoxypropane (TEP), guanidine hydrochloride, ortho-phthalaldehyde (OPA), reduced glutathione (GSH), phosphoric acid, potassium dihydrogen phosphate (KH₂PO₄), hydrochloric acid (HCl), streptozotocin (STZ), ethanol, ethyl acetate, and methanol from Sigma-Aldrich (St. Louis, MO, USA). All HPLC analytical standards, including protocatechuic acid, syringic acid, rutin, ellagic acid, cynaroside, daidzein, neochlorogenic acid, chlorogenic acid, vitexin, trans p-coumaric acid, trans-sinapic acid, trans ferulic acid, rosmarinic acid, resveratrol, apigenin, myricetin, quercetin, and kaempferol, were bought from Sigma-Aldrich (St. Louis, MO, USA). Phosphate buffer saline (PBS) was bought from VWR (Radnor, PA, USA).

Brown rice (Oryza sativa L.), wheat (Triticum aestivum L.) and oat (Avena nuda L.) were procured from local market. Standard phenolic acids (p-hydroxybenzoic acid, chlorogenic acid, vanillic acid, trans-caffeic acid, syringic acid, trans-p-coumaric acid, trans-ferulic acid, trans-sinapic acid) were procured from Sigma-Aldrich (St. Louis, MO, USA), and the cis-phenolic acids (cis-p-coumaric acid, cis-ferulic acid, cis-sinapic acid) were prepared by exposing a known solution of fresh trans-hydroxycinnamic acid to UV light overnight [10 (link)]. 2, 2' azino-bis (3-ethylbenzthiazoline) 6-sulfonic acid (ABTS), Folin-Ciocalteu reagent, digest enzymes (pepsin, pancreatin) were procured from Sigma-Aldrich (St. Louis, MO, USA). Bile extract (porcine origin) were procured from Solarbio (Beijing, China). HPLC-grade solvents were from Xilong (Guangdong, China). All other chemicals and reagents used were of analytical grade.

Methanol and n-hexane were purchased from Honeywell (Charlotte, North Carolina, USA), whereas ethanol was acquired from Scharlab (Barcelona, Spain). Double-deionized water was obtained using a Milli-Q system (Millipore, Bedford, MA, USA). Standards of trans-p-coumaric acid, hydroxytyrosol, tyrosol, maslinic acid, oleanolic acid and oleuropein were purchased from Sigma-Aldrich (St. Louis, MO, USA), and (+)-pinoresinol was acquired from PhytoLab (Vestenbergsgreuth, Germany). Apigenin and luteolin were purchased from LGC (Teddington, Middlesex, UK), and luteolin-7-O-glucoside, loganin and verbascoside were purchased from Extrasynthese (Lyon, France).