The stock standard solution of curcumin and C. longa extract powder had a concentration of
1 mg/mL of curcumin. 0.2 mL of standard and extract powder solution was transferred to 10 mL volumetric flask and dissolved in methanol to give a concentration of 20 lg/mL. This sample was injected into HPLC in triplicate to determine the potency of C. longa
extract powder.