It was found that Phlogacanthus curviflorus (Wall.) Nees var. curviflorus
(Hung Teaw Yam) has the highest DPPH anti-oxidant activity (EC50 = 0.219 mcg),
its FRAP value, expressed as FeSO4 equivalents (mg/g extract), is 949.143 ± 0.074
and its total phenolic content, expressed as gallic acid equivalents (mg/g extract),
equals 17,368.421 ± 0.009.