Vanillin

HPLC grade ethyl acetate, methyl alcohol, acetic acid (99%), formic acid (98–100%) and toluene as well as analytical grade hydrochloric acid (37%), phosphoric acid (85%), ethyl alcohol and dichloromethane were purchased from Sigma-Aldrich (St. Louis, MO, USA) and Merck (Darmstadt, Germany). The anthocyanin standards (cyanidin-3,5-O-diglucoside, cyanidin-3-O-glucoside, delphinidin-3-O-glucoside, malvidin-3,5-O-diglucoside, malvidin-3-O-glucoside, delphinidin) and also (+)-catechin, (−)-epicatechin, (−)-epigallocatechin and (−)-epigallocatechin gallate were provided by Extrasynthese (Genay, Lyon area, France). The reagents for derivatization steps, namely 2-aminoethyl diphenylborinate (natural product reagent A, NP) and polyethylene glycol 400 (PEG 400), were obtained from Sigma Aldrich, while vanillin was bought from BDH (Poole, UK). Bidistilled water was used as solvent for each type of application method, i.e., extraction and sample preparation.

1,1-diphenyl-2-picrylhydrazyl (DPPH), potassium ferricyanide, phosphate buffer, catechin (CA), ferrous ammonium sulphate, butylated hydroxytoluene (BHT), gallic acid (GA), ascorbic acid (AA), trichloro acetic acid (TCA), sodium phosphate, ammonium molybdate, DMSO, EDTA, thiobarbituric acid (TBA) and FeCl₃ were purchased from Sigma Chemical Co. (St. Louis, MO,USA); vanillin was obtained from BDH; Folin-Ciocalteus's phenol reagent (FCR) and sodium carbonate were obtained from Merck (Damstadt, Germany). Ehrlich ascites carcinoma (EAC) cells were obtained with the courtesy of Department of Bio-Chemistry and Molecular Biology, Rajshahi University, Rajshahi, Bangladesh. TRIzole reagent, RNase OUT, dNTPs, Taq polymerase and SuperScript-III reverse transcriptase were purchased from Life Technologies (Invitrogen BioServices India Pvt. Ltd, Bangalore, India); Apo direct kit was purchased from BD Biosciences.