epigallocatechin-3-O-gallate Research Articles

Effects of (-)-epigallocatechin-3-O-gallate (green tea tannin) on the life span of stroke-prone spontaneously hypertensive rats.

1. Effect of (-)-epigallocatechin-3-O-gallate (EGCG), a condensed tannin isolated from green tea leaves, on the life span and hypertensive lesions in the stroke-prone spontaneously hypertensive rat (SHRSP) was compared with that of persimmon tannin. 2. Long-term administration of either 0.5% EGCG or 0.5% persimmon tannin to SHRSP inhibited the incidence of stroke and prolonged the life span, but did not affect the blood pressure. 3. These results indicate that EGCG may prevent incidence of stroke due to the radical scavenging action and inhibition of lipid peroxidation, and may result in prolonging the life span of SHRSP, as in the case of persimmon tannin.

Monoamine metabolites, iron induced seizures, and the anticonvulsant effect of tannins

Intracortical injections of iron ions have been shown to induce recurrent seizures and epileptic discharges in the EEG. (-)-Epigallocatechin (EGC) and (-)-epigallocatechin-3-O-gallate (EGCG), isolated from green tea leaves, have been reported to prevent or diminish the occurrence of epileptic discharges induced by iron ions, and to inhibit catechol-O-methyltransferase. Iron ions significantly increased DOPAC and HVA levels in the intrastriatal perfusate 140 and 180 minutes, respectively, after injection. EGC and EGCG inhibited the increases induced by iron ions. Furthermore, EGCG decreased the HVA level in the perfusate 200 minutes after injection whether or not iron ions were injected. Iron ions had no effect on the 5-HIAA level, and EGC and EGCG raised it. These results suggest that formation of an epileptic focus induced by iron ions might be accompanied by activation of dopaminergic neurons, and that EGC and EGCG inhibit that hyperactivity.