The amount of total phenolic content (TPC) in tea extracts was
determined according to the Folin-Ciocalteu procedure as used by
Molan, Lila, and Mawson (2008a) with some modifications. Briefly,
an aliquot of 12.5 ll of water-soluble extract was mixed with
250 ll of 2% sodium carbonate solution in 96-well microplates
and allowed to react for 5 min at room temperature. Then,
12.5 ll of Folin-Ciocalteu phenol reagent (50%) was added and allowed
to stand for 30 min at room temperature before the absorbance
of the reaction mixture was read at 650 nm using a plate
reader. Calibration was achieved with an aqueous gallic acid solution
(100–1000 lg/ml). The TPC of the extract was expressed as mg
gallic acid equivalent (GAE) per gram of tea leaves on a dry basis.