Ruthenium-Arene Complexes of Curcumin: X-Ray and Density Functional Theory Structure, Synthesis, and Spectroscopic Characterization, in Vitro Antitumor Activity, and DNA Docking Studies of (p-Cymene)Ru(curcuminato)chloro

The in vitro antiproliferative activity of the title compound on five tumor cell lines shows preference for the colon-rectal tumor HCT116, IC50 = 13.98 mu M, followed by breast MCF7 (19.58 mu M) and ovarian A2780 (23.38 mu M) cell lines; human glioblastoma U-87 and lung carcinoma A549 are less sensitive. A commercial curcumin reagent, also containing demethoxy and bis-demethoxy curcumin, was used to synthesize the title compound, and so (p-cymene)Ru(demethoxycurcuminato)chloro was also isolated and chemically characterized. The crystal structure of the title compound shows (1) the chlorine atom linking two neighboring complexes through H-bonds with two O-(hydroxyl), forming an infinite two-step network; (2) significant twist in the curcuminato, 20 degrees between the planes of the two phenyl rings. This was also seen in the docking of the Ru-complex onto a rich guanine B-DNA decamer, where a Ru-N7(guanine) interaction is detected. This Ru-N7(guanine) interaction is also seen with ESI-MS on a Ru-complex-guanosine derivative.