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Updated: Jan 23, 2026

Caffeine Extraction, Enzymatic Activity and Gene Expression of Caffeine Synthase from Plant Cell Suspensions
Published on: October 2, 2018
DNA-binding and in vitro cytotoxic activity of platinum(II) complexes of curcumin and caffeine
Valentina Censi1, Ana B Caballero2, Marta Pérez-Hernández3
1Department of Inorganic and Organic Chemistry, Inorganic Chemistry Section, University of Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain; DICATECh, Politecnico di Bari, via Orabona, 4, 70125 Bari, Italy.
Abstract:
Three Pt(II) complexes containing the natural ligands curcumin and caffeine, namely [Pt(curc)(PPh3)2]Cl (1), [PtCl(curc)(DMSO)] (2) (curc = deprotonated curcumin) and trans-[Pt(caffeine)Cl2(DMSO)] (3), were synthesized and fully characterized. The data obtained suggest that, for both 1 and 2, the anion of curcumin is coordinated to the platinum ion via the oxygen atoms of the β-diketonate moiety. Spectroscopic features reveal that in 2 and 3, a DMSO molecule is S-bonded to the metal centre. For 3, all data indicate a square-planar geometry formed by a 9-N bonded caffeine, two trans chloride anions and a DMSO. The three complexes undergo changes in solution upon incubation for 24 h; 1 and 2 release curcumin while 3 isomerizes from trans to cis configuration. The DNA-binding and cytotoxic properties of 1-3 were evaluated in vitro. Despite their structural similarity, curcuminate-containing 1 and 2 exhibit distinct DNA interactions. While 1 appears to intercalate between nucleobase pairs, inducing the oxidative degradation of the biomolecule, 2 behaves as a groove binder, by means of electrostatic forces. Caffeine-containing 3 exhibits a behaviour that is comparable to that of 2. Complexes 1 and 2 showed moderate to high cytotoxicity and selectivity against several cancer cell lines, while 3 is inactive. Compounds 1 and 2 can be further activated by visible-light irradiation.
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