Acetonitrile for high performance liquid chromatography

(−)-Epigallocatechin (98%), (−)-Epicattechin (98%), Caffeine anhydrous (98.5%), Phosphoric Acid, Ortho (85%), Acetonitrile (99.8%, used for HPLC analysis in this paper) were purchased from Nacalai tesque, Kyoto, Japan. (+)-Catechin Hydrate (>95.0%), (−)-Epicatechin Gallate (>98.0%), (−)-Epigallocatechin Gallate Hydrate (>98%), tert-butyl hydroperoxide (70% in Water) were purchased from Tokyo Chemical Industry, Tokyo, Japan. Acetonitrile for High Performance Liquid Chromatography (99.8+%, used for LC-MS/MS analysis in this paper) and Sodium Carbonate (99.8+%) were purchased from Wako Pure Chemical Industries, Tokyo, Japan. Folin–Denis’ reagent and 2’,7’-dichlorofluorescein diacetate (≥97%, DCFDA) was purchased from Merck KGaA (Sigma-Aldrich), Darmstadt, Germany. Anmonium formate solution, and Formic acid-Acetonitrile were purchased from Kanto Kagaku, Tokyo, Japan. Sodium hexametaphosphate was purchased from Mitejima Chemical, Osaka, Japan. SOD Assay Kit-WST was purchased from Dojindo Molecular Technologies, Kumamoto, Japan.

The α-CD was supplied by Ensuiko Sugar Refining Co., Ltd., and dried overnight in vacuo at 110 °C before use. TrCl (Tokyo Chemical Industry Co., Ltd.), benzyl bromide and mesitylenesulfonyl chloride (Wako Pure Chemical Industries Ltd.) were used without further purification. Commercially available NaH in oil (50–77%) and Pd/C (Pd 10%) were used for the conversion of tri-6-O-trityl-α-CD to tri-6-O-mesitylenesulfonyl-α-CD. Reagent-grade pyridine was dried over CaH₂ and distilled in the presence of CaH₂ before use. N,N-Dimethylformamide (DMF) was also dried over CaH₂ and distilled before use. Acetonitrile for high performance liquid chromatography was purchased from Wako Pure Chemical Industries Ltd. DMSO-d₆ containing 0.05% v/v tetramethylsilane (Cambridge Isotope Laboratiories, Inc., 99.9 atom % D) was used for ¹H NMR measurements.