2.2. Tea samples and preparation
White tea (Silver needle, KWF Food Industries, China), was purchased
from the local market. Tea infusion was prepared by placing
2 g of tea leaves in 100 ml of distilled water at boiling temperature
(100 C) and brewing for 5 min. The sample (Silver needle white
tea infusion) was filtered through Whatman filter paper No. 1
and the water extracts were freeze–dried. The concentrated extract
was diluted appropriately with distilled water according to each
specific assay and stored at 20 C until further analysis.