Cis resveratrol

External standards for 1-kestose, nystose, raffinose, glucose, fructose, rhamnose, maltose and for citric tartaric, lactic and acetic acids were purchased from Sigma-Aldrich (St. Louis, MO, USA). External standards for formic and succinic acids were purchased from Merck (Darmstadt, HE, Germany). External standards for procyanidin A2, epigallocatechin gallate, epicatechin gallate, kaempferol 3-glucoside, quercetin 3-rutinoside (rutin), quercetin 3-glucoside, myricetin, came from Extrasynthese (Genay, France). cis-Resveratrol and trans-resveratrol were obtained from Cayman Chemical Company (Ann Arbor, MI, USA). External standards of the phenolics: gallic acid, p-coumaric acid, chlorogenic acid, syringic acid, trans-caftaric acid, caffeic acid, hesperidin, naringenin, procyanidin B1, catechin, epicatechin and procyanidin B2, were purchased from Sigma-Aldrich. Acetonitrile, methanol, potassium persulfate, gallic acid and ethyl alcohol were obtained from Merck. The ultrapure water was obtained using a Marte Científica purification system (São Paulo, SP, Brazil). The chromogen 3,3′diaminobenzidine tetrachloride was purchased from Vector Laboratories (Burlingame, CA, USA). All antibodies used in this study were purchased from Abcam (Cambridge, MA, UK). All chemical reagents used in the experiments were of analytical grade.