Quercetin

All the chemicals used in this study were of laboratory grade. The Folin–Ciocalteu's phenol reagent (FCR), α-amylase and acarbose were obtained from Sigma Aldrich, St. Louis, MO, USA. The solvent ethanol and methanol (Qualigens Fine Chemicals) were purchased from the local city of Kathmandu, Nepal. Sulphuric acid, hydrochloric acid, aluminium chloride, sodium chloride, sodium carbonate, dimethyl sulphoxide, potassium acetate, disodium hydrogen phosphate dihydrate, and sodium dihydrogen phosphate dihydrate (Thermo-Fisher Scientific India) were purchased from Kathmandu, Nepal. quercetin and gallic acid (Hi-media Laboratories) were procured from the local city of Kathmandu, Nepal. The 1,1-diphenyl-2-picrylhydrazyl (DPPH), gallic acid and quercetin (Wako Pure Chemicals, Osaka, Japan), were purchased from the local city of Kathmandu, Nepal.

All prostanoids (PGE₃, PGF_3α, TXB₃, PGE₂, PGF_2α, and TXB₂), deuterated prostanoids (PGE₂-d4, PGF_2α-d4, and TXB₂-d4), and EPA were purchased from Cayman Chemical Co. (Ann Arbor, MI). Calcium ionophore A23187 and indomethacin were purchased from Sigma Aldrich (St. Louis, MO). Adenosine 5′-triphosphate (ATP) disodium salt hydrate, 5′-adenylic acid (AMP), and sodium creatine phosphate hydrate were purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan). Creatine kinase was purchased from Roche Applied Science (Tokyo, Japan). Dipyridamole, probenecid, quercetin, methotrexate, and folic acid were purchased from Wako Pure Chemical Industries (Osaka, Japan). MK571, celecoxib, candesartan, estradiol 17β-glucronide (E₂17βG), adenosine 3′, 5′-cyclic monophosphate (cAMP), and guanosine 3′, 5′-cyclic monophosphate (cGMP) were purchased from Sigma Aldrich (St. Louis, MO). All other chemicals were of the highest purity available.

We examined the inhibitory activities of food constituents in cell proliferation assays. Test compounds used in the assays were as follows: curcumin (Wako or Sigma-Aldrich), zerumbone (Wako), genistein (Sigma-Aldrich), chalcone (Wako), corosolic acid (Wako), carnosol (Wako), ursolic acid (Wako), epigallocatechin (Sigma-Aldrich), isoflavone (Wako), apigenin (Wako), chrysin (Wako), flavanone (Wako), resveratrol (Wako), flavone (Wako), quercetin (Wako), daidzein (Wako), and clodronate (Sigma-Aldrich). These compounds were firstly dissolved with dimethyl sulfoxide (DMSO; Wako) and then appropriately diluted with RPMI1640 + 10% FCS to apply the assays. The final concentration of DMSO was adjusted not to exceed 1% at most in cell cultures.

Flavone, 6-hydroxy flavone, 3-hydroxy flavone, 7-hydroxy flavone, 6-methoxy-flavone, 6-methoxy flavanone, naringenin and naringin were purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan). Biochanin A, genistein, apigenin, puerarin, wogonin, catechin (C), epicatechin (EC), luteolin, daidzein, daidzin, resveratrol, piceid and neohesperidin-dihydrochalcone were purchased from Aladin Co. Ltd. (Shanghai, China). Galangin, kaempferol, quercetin, myricetin, baicalein and chrysin were purchased from Wako Pure Chemical Industries (Osaka, Japan). All other polyphenols were obtained commercially from Shanghai Tauto Biotech CO., Ltd. (Shanghai, China). Peptone, yeast extract, agar, 1-deoxy-1-morpholino fructose (DMF) and bovine serum albumin (BSA) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Nitrotetrazolium Blue chloride (NBT) was obtained from Sinopharm Chemical Reagent Co., Ltd. (Beijing, China). Kanamycin and carbenicillin were purchased from Shanghai Xinya Pharmaceutical Co., Ltd. (Shanghai, China). Fetal bovine serum (BP) of no phage and low endotoxin was from Sijiqing Biological Engineering Materials Co., Ltd. (Hangzhou, China). All other reagents and solvents were analytical grade and used without further purification.

ISO was synthesized from quercetin (Fujifilm Wako Pure Chemical Corp., Tokyo, Japan) following the protocol of the National Institute of Advanced Industrial Science and Technology (Kato et al., 2016 (link)) and was used for in vitro and in vitro experiments. AgII was purchased from Wako Pure Chemical Industries Ltd (Osaka, Japan).