ABSTRACT: Tert-butyl curcumin (TBC), demethylated tert-butylated curcumin (1E,6E-1,7-bis(3-tert-butyl-4,5-dihydroxyphenyl)hepta-1,6-diene-3,5-dione, DMTC), demethylated curcumin (DMC), and Cur were synthesized from the starting compound, 2-methoxy-4-methylphenol. TBC and DMTC are two novel lipophilic compounds, and Cur and DMC are polar and hydrophilic. The antioxidant activities of Cur, TBC, DMC, and DMTC were evaluated by using the methods of 2,2-diphenyl-1-(2,4,6-trinitro-phenyl)-hydrazinyl (DPPH), deep-frying, and Rancimat. Tert-butylhydroquinone (TBHQ) and Butylated hydroxytoluene (BHT) were used as comparison compounds. Both Rancimat and deep-frying tests demonstrated that DMTC was the strongest antioxidant, and TBC also had stronger antioxidant activity than Cur. In the DPPH assay, DMC showed
