1 4 benzoquinone

1,4-Benzoquinone and 37% formaldehyde solution were purchased from Sigma Co. (Sigma, St. Louis, MO, USA). Corn oil was obtained from COFCO (Beijing, China). The Chip Enzymatic Chromatin IP Kit was purchased from Univ Corp (CST, Danvers, MA, USA). The HIF-1α antibody was supplied by Univ Corp (NOVUS, Littleton, CO, USA).

Citric acid-1-hydrate (Bendosen, Laboratory Chemicals, Johor Bahru, Malaysia); ethylenediamine; glycerol; ethanol, 98%; hydrochloric acid, HCl 37%; phosphate-buffered saline (PBS) (QREC, Grade AR, (Asia) Sdn. Bhd, Rawang, Selangor, Malaysia); titanium(IV) tetraisopropoxide, TTIP ≥ 97% purity; commercial pure anatase, ≥99%; sodium pyruvate; dimethyl sulfoxide, DMSO; 1,4-benzoquinone (Sigma-Aldrich, Co., St. Louis, MO, USA); phosphate buffered saline (PBS) (Sigma-Aldrich, Co., Taufkirchen, Germany); Dulbecco’s modified Eagle’s medium, DMEM; penicillin-streptomycin solution, 10,000 units/mL (Nacalai Tesque, Nakagyo-ku, Kyoto, Japan); fetal bovine serum (FBS) (TICO Europe, DJ, Amstelveen, The Netherlands); CellTiter 96^® AQueous One Solution Cell Proliferation Assay (MTS); Caspase-Glo^® 3/7 Assay (Promega, Madison, WI, USA); 2′,7′-dichlorofluorescein diacetate (DCFDA, Merck-Millipore, Burlington, MA, USA); tetramethylrhodamine ethyl ester; TMRE-Mitochondrial Membrane Potential Assay Kit (Abcam, Trumpington, Cambridge CB2 0AX, UK) were used as purchased without any further purification.

β-Nicotinamide adenine dinucleotide reduced disodium salt hydrate (NADH), β-nicotinamide adenine dinucleotide sodium salt hydrate (NAD+), β-nicotinamide adenine dinucleotide 2′-phosphate reduced tetrasodium salt hydrate (NADPH), 1,4-hydroquinone, 1,4-benzoquinone, and L(+)-ascorbic acid sodium salt (vitamin C sodium salt) were purchased from Sigma-Aldrich (USA). H₂O₂, nitrate, and nitrite test strips were purchased from Bartovation LLC (New York, NY, USA). These strips were used for the detection of H₂O₂, NO₂⁻, and NO₃⁻ in water after the treatment with cold atmospheric pressure He-plasma jet. Time of the aqueous solution treatment was shown in Figure 3. Bottled ultra-high purity helium was purchased from Sexton Welding Supply (Huntsville, AL, USA).

Total CoQ coenzyme content was determined according to [40 (link)], with minor modifications. Tissue homogenate (100 µL 10% homogenate + 100 µL water) was vortexed with the addition of 50 µL 1,4-benzoquinone (2 mg/mL; Sigma-Aldrich, Saint Louis, MO, USA) and left for 10 min at room temperature. Then, 1 mL of propan-1-ol was added and the mixture was vortexed properly. Samples were centrifuged (26,000× g, 20 min, 4 °C) and the acquired supernatant was used for HPLC measurement. The amount of CoQ was measured using HPLC Pharmacia on reverse-phase Supercosil LC 18 and LC 18S (Supelco) column with an in-line filter (Upchurch Scientific), mobile phase ethanol:methanol, 7:3, 1 mL/min, detection at 275 nm using standard CoQ₁₀ solution (TANAKA, Tokyo, Japan) [40 (link),41 (link)] and CoQ₉ solution (Sigma-Aldrich, Saint Louis, MO, USA). The CoQ content in the tissue homogenate was expressed in pmol per milligram of protein.

In this study, the following chemicals and materials were used. Ammonium hydroxide (NH₄OH, 28%), ammonium vanadate (NH₄VO₃, 99%), ferric chloride anhydrous (FeCl₃, 99.9%), zinc chloride anhydrous (ZnCl₂, 99.9%), tert-butyl alcohol ((CH₃)₃COH, 98.5%), 1,4-benzoquinone (C₆H₄O₂, 99%), and ammonium oxalate ((NH₄)₂C₂O₄, 99%) are provided from Sigma-Aldrich. The malachite green (MG) dye (C₂₃H₂₅N₂Cl; MW = 364.92 g) is provided from Fluka. All chemicals used in this study were analytical grade and utilized without additional purification.

Anthraquinone (99% Fluka), 1,4-naphthoquinone (96.5% Fluka), 1,4-benzoquinone (99+%, Sigma), anhydrous MgCl₂ (ultra-dry 99.99% Alfa Aeasar), anhydrous AlCl₃ (99.985% Alfa Aeasar), carbon black Printex XE2 and polytetrafluoroethylene (PTFE) water dispersion (60% in water, Sigma Aldrich) were all used as received. Mg(TFSI)₂ (Solvionic 99.5%) was dried for at least 24 h at 250 °C in vacuum before use. Dimethoxyethane (DME) (99% Honeywell) was dried with molecular sieves for several days, mixed with Na/K alloy (approx. 1 mL/L) overnight and afterwards, fractionally distilled. Anthracene-9,10-diol was prepared by the reduction of anthraquinone in dimethylsulfoxide with NaBH₄. Afterwards, anthracene-9,10-diol was dissolved in tetrahydrofuran and reacted with Bu₂Mg in heptane. The reaction mixture was dried to obtain brick red product magnesium anthracene-9,10-bis(olate) coordinated with tetrahydrofuran solvent. Electrolytes were prepared by adding the appropriate amount of salts into measuring flasks, mixing overnight, and finally, diluting them up to the mark to obtain 0.6 M Mg(TFSI)₂-2MgCl₂ and 0.6 M MgCl₂‒AlCl₃ in DME.

Triptycene-1,4-diol (TRP) (Wiegand et al., 2014 (link)) and pentiptycene-6,13-diol (PENT) (Luo et al., 2015 (link)) were synthesized according to previous literature. Anthracene, sodium hydrosulfite, 4,4′-dichlorodiphenylsulfone (DCDPS), and 4,4′-difluorodiphenylsulfone (DFDPS) were purchased from Alfa Aesar and used as received. 1,4-benzoquinone, tetrachloro-1,4-benzoquinone, potassium carbonate (K₂CO₃), sodium bicarbonate, acetic acid, methanol, and 2-propanol were purchased from Sigma-Aldrich. 4,4′-biphenol (BP) and 3,3′-disulfonated-4,4′-dichlorodiphenylsulfone (SDCDPS) were purchased from Akron Polymer Systems and dried in vacuum at 110°C for 24 h before use. Anhydrous N, N-dimethylacetamide (DMAc), toluene, and hydrogen peroxide (30 wt% solution) were purchased from EMD Millipore and used as received.