Remarkable enhancement in photocytotoxicity and hydrolytic stability of curcumin on binding to an oxovanadium(iv) moiety

Author(s): Samya Banerjee ¹ ^, ² ^, ³ ^, ⁴ , Ila Pant ⁵ ^, ⁶ ^, ² ^, ³ ^, ⁴ , Imran Khan ⁵ ^, ⁶ ^, ² ^, ³ ^, ⁴ , Puja Prasad ¹ ^, ² ^, ³ ^, ⁴ , Akhtar Hussain ¹ ^, ² ^, ³ ^, ⁴ , Paturu Kondaiah ⁵ ^, ⁶ ^, ² ^, ³ ^, ⁴ , Akhil R. Chakravarty ¹ ^, ² ^, ³ ^, ⁴

Publication date (Electronic): 2015

Journal: Dalton Transactions

Publisher: Royal Society of Chemistry (RSC)

Read this article at

ScienceOpenPublisher PubMed

Bookmark

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

Polypyridyl oxovanadium( iv) curcumin complexes show remarkable hydrolytic stability and visible light-induced photocytotoxicity in cancer cells by mitochondria targeting ROS-mediated apoptosis.

Abstract

Oxovanadium( iv) complexes of polypyridyl and curcumin-based ligands, viz. [VO(cur)(L)Cl] ( 1, 2) and [VO(scur)(L)Cl] ( 3, 4), where L is 1,10-phenanthroline (phen in 1 and 3), dipyrido[3,2- a:2′,3′- c]phenazine (dppz in 2 and 4), Hcur is curcumin and Hscur is diglucosylcurcumin, were synthesized and characterized and their cellular uptake, photocytotoxicity, intracellular localization, DNA binding, and DNA photo-cleavage activity studied. Complex [VO(cur)(phen)Cl] ( 1) has V ^IVN ₂O ₃Cl distorted octahedral geometry as evidenced from its crystal structure. The sugar appended complexes show significantly higher uptake into the cancer cells compared to their normal analogues. The complexes are remarkably photocytotoxic in visible light (400–700 nm) giving an IC ₅₀ value of <5 μM in HeLa, HaCaT and MCF-7 cells with no significant dark toxicity. The green emission of the complexes was used for cellular imaging. Predominant cytosolic localization of the complexes 1–4 to a lesser extent into the nucleus was evidenced from confocal imaging. The complexes as strong binders of calf thymus DNA displayed photocleavage of supercoiled pUC19 DNA in red light by generating ˙OH radicals as the ROS. The cell death is via an apoptotic pathway involving the ROS. Binding to the VO ²⁺ moiety has resulted in stability against any hydrolytic degradation of curcumin along with an enhancement of its photocytotoxicity.