The triplet state of tanshinone I and its synergic effect on the phototherapy of cancer cells with curcumin

The excited triplet state of tanshinone I (Tan I) extracted from the traditional Chinese medicine Salvia miltiorrhiza Bunge was characterized by laser flash photolysis. The synergic effect of Tan I on the phototherapy of cancer cells with curcumin (Cur) was also investigated by MTT assay because the excited energy transfer from the triplet state of Tan I ( 3 Tan I ∗ ) to Cur occurred. At the same time, the characteristic absorption spectra of 3 Tan I ∗ were recorded, and its molar absorption coefficient and rate constants for several excited energy transfers were obtained. The photo-therapeutic effect of Cur is enhanced by combination with Tan I.