6 hydroxy 2 5 7 8 tetramethylchromane 2 carboxylic acid

The reagents of analytical grade were purchased from Sigma/Aldrich (St. Louis, MO): β-carotene, 2,6-di-tert-butyl-4-methylphenol (BHT), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), Folin-Ciocalteu reagent, disodium fluorescein, 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH), chemical standards (gallic acid, rutin hydrate, caffeic acid, kaempferol, and catechin), 1-nitropyrene (1-NP), dimethyl sulfoxide (DMSO). HPLC grade organic reagents were from Baker Inc. (Philipsburg, PA).

Folin-Cioclateu’s phenol reagent, gallic acid, porcine pancreatic α-amylase (Type VI-B), rat intestinal acetone powder, 3,5-dinitrosalicylic acid, bovine serum albumin (BSA, fraction V), aminoguanidine hydrochloride (AG), guanidine hydrochloride, thioflavin T, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), and 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ), delphinidin-3-glucoside (D3G) were purchased from Sigma-Aldrich Co. (St. Louis, MO, USA). 2,4-dinitrophenylhydrazine (DNPH), D-maltose, D-fructose, D-glucose, sucrose, and iron (II) sulfate were purchased from Ajax Finechem (Taren Point, Australia). Trichloroacetic acid (TCA) was purchased from Merck (Darmstadt, FR, Germany). A glucose liquid color kit was purchased from HUMAN Gesellschaft für Biochemica und Diagnostica mbH (Wiesbaden, Germany). Acarbose was purchased from Bayer AG Pharmaceutical (Berlin, Germany). Cyanidin-3-O-glucoside (C3G) was obtained from PhytoLab GmbH & Co. KG (Vestenbergsgreuth, Germany). All other chemicals used in this study were analytical grade.

The total antioxidant capacity (TAC) of serum and peritoneal fluid samples of septic mice from the pretreatment (12 and 24 h after PLC induction) and posttreatment (7 days postsurgery) groups was evaluated by (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Sigma-Aldrich, St. Louis, MO, USA) equivalent antioxidant capacity assay. In this assay, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) (Sigma-Aldrich, St. Louis, MO, USA) was incubated with potassium persulphate (Sigma-Aldrich, St. Louis, MO, USA) to produce ABTS^·+, a green/blue chromophore. The inhibition of ABTS^·+ formation by antioxidants in the samples was expressed as Trolox equivalents, determined at 740 mm using a calibration curve plotted with different amounts of Trolox (Sigma-Aldrich, St. Louis, MO, USA) [29 (link)].

Fatty acid methyl esters, AR (C15, C17, C19 and C25), phenolic (ferulic, vanillic and syringic acids, vanillin and p-OH-benzaldehyde), tocopherol standards (α, β, δ and γ), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 6-Hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), 2,2-diphenyl-1-picryhydrazyl (DPPH) and 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ), were purchased from Sigma–Aldrich Co. (St. Louis, MO, USA). Syringic aldehyde was supplied by Extrasynthese (Genay, France), methyl tricosanoate by Larodan (Malmö, Sweden) and K₂O₈S₂, FeCl₃ and FeSO₄ were purchased from Panreac (Barcelona, Spain).

Two acetogenin samples (Annonacin and pseudoannonacin) from A. muricata pulp were provided by Zepeda-Vallejo’s research group (Department of Organic Chemistry of the National School of Biological Sciences, National Polytechnic Institute, Mexico City, Mexico). The chemical structure of the above acetogenins was established based on semipreparative-HPLC, HPLC–MS, and NMR analysis. The purity of each sample was determined to be above 95%. Silica gel, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid; 2,2-diphenyl-1-picrylhydrazyl; methanol, acetonitrile, 3,5-hydroxybenzoic acid, 2,4,6-tripyridyl-s-triazine, 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid, ferric chloride hexahydrated and water-HPLC grade were purchased from Sigma-Aldrich Co. Ltd. (St. Louis, MO, USA). Petroleum ether, potassium hydroxide, dichloromethane, ethyl acetate, hexane, chloroform, ethanol, and acetone, all analytical grade, were purchased from Jalmek Scientific S.A., Guadalajara, Jalisco, Mexico.

The burdock (Arctium lappa L.) roots of the Yanagawarisou variety that were harvested in April 2020, were purchased from Jiali District Farmers’ Association in Tainan City, Taiwan (R.O.C.). The chemical reagents, (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid, 2,4,6-tris(2-pyridyl)-s-triazine, 3,5-dinitrosalicylic acid, Folin & Ciocalteu’s phenol reagent, gallic acid, ferrous sulfate heptahydrate, and ferric chloride were purchased from Sigma-Aldrich Co. (St. Louis, MO, USA). The purchased reagents used as standard in analysis were chlorogenic acid from Sigma-Aldrich Co. (St. Louis, MO, USA), cynarin and inulin from Toronto Research Chemicals Inc. (Toronto, ON, Canada), and fructose from Chem Service Inc. (West Chester, PA, USA). Other chemicals were purchased from Bionovas biotechnology Co. (Toronto, ON, Canada), Merck (Darmstadt, Germany), Sigma-Aldrich Co. (St. Louis, MO, USA), and IT’S Science Corporation Ltd. (New Taipei City, Taiwan).

Acetic acid, ethanol 96%, methanol, and sucrose were from Chempur (Piekary Śląskie, Poland). HPLC-grade methanol and acetonitrile were purchased in Merck (Darmstadt, Germany).
Plant culture media components, plant growth regulators BA (6-benzyladenine) and NAA (1-naphthaleneAcetic acid) and agar were purchased in Duchefa Biochemie (Haarlem, Netherlands). Cultures were grown in the plant tissue-dedicated glass containers (V8630, Sigma-Aldrich, Saint Louis, MI, USA).
Commercially available standards: chlorogenic acid, cryptochlorogenic acid, and neochlorogenic acid, hyperoside (quercetin 3-galactoside), isoquercitrin (quercetin 3-glucoside), isorhamnetin, kaempferol, guaijaverin (quercetin 3-arabinoside), quercetin, rutoside (quercetin 3-rutinoside), and trifolin (kaempferol-3-galactoside) of HPLC grade (≥95.0%) purity were acquired in Sigma-Aldrich Saint Louis, MI, USA. Ammonium acetate, CuCl₂⋅2H₂O, DPPH, FeCl₃⋅6H₂O, Folin-Ciocalteu reagent, hydrochloric acid (HCl), Na₂CO₃, 2,9-dimethyl-1,10-phenanthroline (neocuprine), 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ), and (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (trolox) were also provided by Sigma-Aldrich. Deionised water (>15 MΩ) was produced in house (PureLab OptionR, Elga, High Wycombe, UK).