A variety of polyphenol antioxidant compounds derived from natural products have demonstrated neuroprotective activity against neuronal cell death. The objective of this study was to investigate the effect of resveratrol (RESV) and bioflavonoids in attenuating hydrogen peroxide (H(2)O(2))-induced oxidative stress in neuronal cells. H2O2 levels were increased by the addition of L-3,4-dihydroxyph...

Green tea catechins have various potential health benefits in humans including anti-inflammatory, anti-oxidative and hepato-protective effects. If present in the circulation, they might have similar effects in ruminants, which are exposed to oxidative stress and fatty liver disease such as dairy cows during the periparturient phase. However, the bioavailability of a substance is a prerequisite ...

The phenolic profile and antioxidant activities of oolong tea extract were investigated after tea was steeped in 90 or 100 C water for 3 or 10 min. The extraction yield increased with increasing temperature and extended steeping time. However, higher temperature and longer time (100 C water for 10 min) led to loss of phenolics. The aqueous extract of oolong tea (AEOT) at 100 C for 3 min exhibit...

Green tea catechins, including (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG), are oxidized and dimerized during the manufacture of black tea and oolong tea to form orange-red pigments, theaflavins (TF), a mixture of theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3'-gallate (TF2B) and theaflavin-3,3'-digallate (...

The preventive effects of C-2 epimeric isomers of (-)-epigallocatechin-3-O-gallate (EGCG) and the O-methylated derivative, (-)-epigallocatechin-3-O-(3-O-methyl)gallate (EGCG3''Me), against ovalbumin-induced type I allergy in male mice were investigated. EGCG and EGCG3''Me exhibited strong antiallergic effects by oral administration at doses of 25 and 50 mg/kg body weight. The antiallergic effec...

A simple, rapid and reliable method of high performance liquid chromatography (HPLC) was developed for the simultaneous determination of bioactive compounds in oolong teas. The optimized method consisted of the use of a C18 reversed-phase column, an isocratic elution system (2 ml/min) of water:acetonitrile (87:13) containing 0.05% trifluoroacetic acid and the detection wavelength of 210 nm. The...

Chisocheton balansae C.DC., is one of the Meliaceae family plants which endemic from Soputan Mountain, North Sulawesi, Indonesia. This study was aimed to determine chemical structure flavan-3-ol compounds ethyl acetate extract C. C.DC stembark. Dried powder stem bark extracted consecutively with n-hexane, acetate, and methanol solvents. Four compounds, named catechin (1), epicatechin (2), epiga...

BACKGROUND/AIMS: Tea, produced from the evergreen Camellia sinensis, has reported therapeutic properties against multiple pathologies, including hypertension. Although some studies validate health benefits of tea, few have investigated molecular mechanisms action. The KCNQ5 voltage-gated potassium channel contributes to vascular smooth muscle tone and neuronal M-current regulation. METHODS: We ...

The structure of the complex between the heptapeptide Gln-Gly-Arg-Pro-Pro-Gln-Gly and the polyphenol (-)-epigallocatechin gallate (EGCG) has been determined using time-averaged nuclear Overhauser effects. Effective parameters for the force constant and time constant have been derived, allowing rapid and efficient calculation of structures that satisfy the input restraints. By using multiple sta...

although several methods have been developed to make gamma-aminobutyric acid (gaba) accumulate in tea, the active ingredients and health benefits vary widely depending on the manufacturing process of tea products. in this study, the levels of bioactive compounds and antioxidant activity in tea leaves given the continuous anaerobic condition were investigated. gaba and other free amino acids suc...