Determination of total phenolic content —
The total phenolic content of the TSCEs was determined by
using a modified Folin-Ciocalteu method18.
Briefly,
0.5 mL of 50ไมโครกรัมต่อมิลลิลิตรTSCEs solution was mixed with
0.5 mL of 1 N Folin-Ciocalteu reagent for 3 min, and
0.5 mL of 1% Na2CO3 was added and incubated for
2 h in a dark room. The reaction mixture was
measured at 760 nm using a spectrophotometer
(Spectronic Genesys 5, Rochester, NY, USA). The
total phenolic content was calculated from a
calibration curve of gallic acid standard and was
expressed as grams of gallic acid equivalent (GAE)
per 100 g of the dry extract.