Catechin content and free radical scavenging activity of Camellia sinensis twig extracts.

The catechin content and antioxidant properties of various Camellia sinensis twig extracts, including a water extract (WE), 10% ethanol extract (10% EE), 50% ethanol extract (50% EE), and 95% ethanol extract (95% EE) were investigated. The 50% EE had the highest total phenolic content (161.3 ± 8.5 mg gallic acid equivalents/L) and total flavonoid content (278.9 ± 12.2 mg quercetin equivalents/L). High-performance liquid chromatography analysis suggested that epigallocatechin gallate and epigallocatechin were the predominant catechins in the twig extracts. The relative concentrations of six catechins isolated from the extracts were: 50% EE > 10% EE > WE > 95% EE. The 50% EE showed free radical-scavenging activity. The concentration of dry matter of 50% EE required to scavenge 50% of ABTS radicals was 102.8 ± 4.2 μg/mL. These results suggest that 50% EE can potentially be used as a source of catechins. [ABSTRACT FROM AUTHOR]