2 2 diphenyl 1 picrylhydrazyl dpph 6 hydroxy 2 5 7 8 tetramethylchroman 2 carboxylic acid trolox

Viscum articulatum Burm. f. (CMC) and Viscum liquidambaricolum Hayata (CMP) were purchased from Pu’er, Yunnan province, China in 2016. Standard phenolic compounds (gallic acid, protocatechuic acid, chlorogenic acid, caffeic acid, p-coumaric acid, (−)-epigallocatechin, myricetin, kaempferol, apigenin, epicatechin, quercetin, vanillic acid, syringic acid, trans-cinnamic acid, catechin, ferulic acid, p-hydroxybenzoic acid and vanillin) were purchased from Beijing Beina Chuanglian Biotechnology Institute (Beijing, China). Folin-Ciocalteu phenol reagent, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), 2,2-diphenyl-1-picrylhydrazyl (DPPH) were obtained from Sigma-Aldrich (St. Louis, MO, USA). 2,4,6-Tripyridyl-s-triazine (TPTZ), 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), trichloroacetic acid, ferric chloride, ascorbic acid, ferrous sulfate, potassium ferricyanide, sodium phosphate dibasic, sodium phosphate monobasic dihydrate, H₂O₂, aluminum chloride and potassium persulfate were purchased from Aladdin Industrial Corporation (Shanghai, China). HPLC-grade methanol and formic acid were purchased from Merck (Darmstadt, Germany). All chemicals used in the experiments were of analytical grade.

Ethanol absolute was obtained from Carlo Erba (Milan, Italy). Acetic acid, acetonitrile, methanol, and water (high performance liquid chromatography—HPLC grade) were purchased from VWR (Milan, Italy).
α-pinene, β-pinene, linalool, β-myrcene, terpinolene, caryophyllene, humulene, and β-bisabolene, gallic acid, p-OH benzoic acid, chlorogenic acid, vanillic acid, caffeic acid, syringic acid, ferulic acid, and rosmarinic acid (from Sigma-Aldrich, Darmstadt, Germany) standards were employed. Working standard mixtures were prepared by appropriate dilution of the standards in methanol. All solutions were stored at −20 °C in the dark.
Folin–Ciocâlteu’s reagent, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), 2,2-diphenyl-1-picrylhydrazyl (DPPH˙), and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS˙⁺) were purchased from Sigma-Aldrich (Darmstadt, Germany). Sodium carbonate, potassium persulfate, potassium hexacyanoferrate(III), trichloroAcetic acid, ferric chloride, and potassium phosphate monobasic were obtained from Carlo Erba (Milan, Italy).

Gallic acid, acetonitrile of HPLC grade (≥99.9%), 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ), sodium acetate, ferric chloride hexahydrate, ferrozine, ammonium acetate and disodium ethylenediaminetetraacetate dihydrate were all obtained from Sigma-Aldrich (St. Louis, MO, USA). Hydrochloric acid (HCl), sodium chloride (NaCl) and monosodium glutamate (MSG) solutions were purchased from Chem-Lab NV (Zedelgem, Belgium). Water was purified by a Milli-Q water purification system (Millipore Corp., Bedford, MA, USA). All other chemicals were of analytical grade and reagents were prepared according to standard analytical procedures.