TPC of the LHT extracts was analyzed spectrometrically
according to the FolineCiocalteu method (Dewanto, Wu, Adom, &
Liu, 2002). Briefly, 100 ml of LHT extract or gallic acid standard
solution was mixed with 2 ml of 2% (w/v) sodium carbonate solution.
The mixture was then incubated for 3 min, after which 100 ml
of FolineCiocalteu reagent was added. After standing for 30 min at
room temperature for color development, absorbance was
measured at 750 nm using a spectrophotometer (UV mini-1240,
Shimadzu, Kyoto, Japan). Results are expressed as mg gallic acid
equivalents (GAE) per g dry-matter of herbal tea.