gallocatechin-3-gallate and myricetin

Phenolic profile of 13 grapevine varieties was determined, with respect to three different parts of berries: skin, seed and pulp. Identification and quantification of the phenols was done using ultra-high performance liquid chromatography (UHPLC) coupled with a diode array detector and a triple-quadrupole mass spectrometer. The most abundant phenols in grape seeds were found to be flavan-3-ols, most of which are gallocatechin gallate and catechin. The skins were characterized mostly by flavonols, i.e. quercetin and myricetin. Characterization of anthocyanins in the berry skin by UHPLC coupled with Linear Trap Quadrupole and OrbiTrap mass analyzer revealed a total of twenty derivatives of malvidin, delphinidin, petunidin, cyanidin, and peonidin. To the extent of our knowledge this is the first work that shows the presence of malvidin 3,5-O-dihexoside in the berry skin of 'Merlot', 'Cabernet Franc', 'Shiraz' 'Sangiovese', 'Pinot Noir' and 'Prokupac', untypical for Vitis vinifera Linneo species.

Topics: Anthocyanins; Catechin; Chromatography, High Pressure Liquid; Flavonoids; Flavonols; Food Analysis; Free Radical Scavengers; Fruit; Mass Spectrometry; Phenols; Plant Extracts; Polyphenols; Seeds; Serbia; Vitis

In this study, green tea compounds (flavonoids, alkaloids, and phenolic acids) were analyzed in green tea-containing dentifrices, and their stability at different pH levels was evaluated. The compounds were separated under 0.01% phosphoric acid-acetonitrile gradient conditions and detected by photodiode array detector at 210, 280, 300, 335 nm. Column temperature was set at 20°C based on the results of screening various temperatures. Each compound showed good linearity at optimized wavelength as well as showing good precision and accuracy in dentifrices. Using this method, the stability of compounds was investigated in pH 4, 7, 8, and 10 solutions for 96 h, and in pH 7 and pH 10 solutions for 6 months. The green tea compounds were more stable at low pH levels; purine alkaloids were more stable than flavonoids. In particular, gallocatechin (GC), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin gallate (GCG), and myricetin almost disappeared in pH 10 solutions after 96 h. In dentifrices, the compounds were gradually decreased until 6 months in both pH types, while gallic acid was increased because of production of galloyl ester of other green tea compounds. Therefore, it is beneficial to adjust to as low a pH as possible when produce green tea-containing dentifrices.

Topics: Catechin; Chromatography, Liquid; Dentifrices; Flavonoids; Hydrogen-Ion Concentration; Tea; Temperature; Toothpastes