Eleutheroside e

Nitrotetrazolium blue chloride (NBT), xanthine, xanthine oxidase, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), potassium persulfate, 3-(2-Pyridyl)-5,6-diphenyl-1,2,4-triazine-p,p′-disulfonic acid monosodium salt hydrate (ferrozine), iron (II) chloride tetrahydrate (FeCl₂ × 4H₂O, 1,3,5-Tri(2-pyridyl)-2,4,6-triazine (TPTZ), iron (III) chloride (FeCl₃), aluminum chloride (AlCl₃), potassium acetate, Folin−Ciocalteu reagent, sodium nitrite, sodium molybdate, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), ascorbic acid, 2(3)-t-Butylhydroquinone monomethyl ether (BHA), 2(3)-t-Butyl-4-hydroxyanisole, hyaluronic acid (IV), escin, hyaluronidase from bovine testes, hexadecyltrimethylammonium bromide (CTAB), L-tyrosine, koji acid, and tyrosine from mushrooms were purchased from Sigma-Aldrich Corp. (St. Louis, MO, USA). The standards of eleutheroside B ≥98.0% (HPLC), eleutheroside E ≥98.0% (HPLC), eleutheroside E1 ≥98.0% (HPLC), protocatechuic acid ≥97%, p-hydroxybenzoic acid 99%, vanillic acid ≥97%, caffeic acid ≥98%, and ferulic acid ≥99% were also purchased from Sigma-Aldrich. Solvents used for extraction were purchased from Avantor Performance Materials (Gliwice, Poland).

The following chemicals were purchased from Sigma-Aldrich (Schnelldorf, Germany): 2-(4-carboxyphenyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazol-1-yloxy-3-oxide potassium salt (^●cPTIO, C221), (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox; 238813), caffeic acid (CA, C0625, purity ≥ 98.0%), eleutheroside B (EB, 90974, purity ≥ 98.0%), eleutheroside E (EE, 08198, purity ≥ 98.0%), L-methionine (MET, M9625), L-cysteine hydrochloride (Cys, C1276), L-glutathione reduced (GSH, G4251), glutathione oxidized (GSSG, G-6654), L-cystine dihydrochloride (cystine, C-6727), diethylenetriaminepentaacetic acid (DTPA, D6518), sodium phosphate monobasic (NaH₂PO₄, S5011) and sodium phosphate dibasic (Na₂HPO₄, S7907). Chlorogenic acid (CGA, PHR2202, purity 97.2%) was from Supelco (Schnelldorf, Germany), and protocatechuic acid (PCA, PHL89766, purity ≥ 98.0%) from Merck (Taufkirchen, Germany). Stock solutions (10 mmol L⁻¹) of Cys and GSH were prepared just before application. Na₂S (100 mmol L⁻¹), polysulfides Na₂S₂, Na₂S₃ and Na₂S₄ (20 mmol L⁻¹) were prepared in argon-bubbled deionised distilled H₂O, immediately frozen at −80 °C and used just after thawing.