Primary screening for antitumor activity of Tetracyclineplatinum(II) complex using Ultraviolet spectroscopy

In order to further clarify the molecular basis for the mechanism of action of the antitumorPt(II) complexes, this work represent a study of the interaction of Pt(II) complex with calfthymus DNA and Human Serum Albumin (HAS) using UV-spectroscopy in vitro, this techniquewas used in order to gain quantitative information regarding the relative binding affinity of theplatinum compounds for calf thymus DNA versus HAS.Spectra of solution of Pt(II) complex (0.07 mM ) at pH7 was recorded at regular intervals inthe absence and presence of calf thymus DNA (0.05mM) and HAS (0.16μM). The presentstudy reveals that the UV spectrum of Cis-dicloro(tetracycline) platinum(II) complex [(Tet.)PtCl2] at pH7 pale yellow solution shows a maximum absorbance at 272nm and a shoulder peak at364nm after 0.25h and 1 hr . These peaks are rapidly diminished with time due to rapidhydrolysis of the nephthacene rings to give a precipitate and loss of the pale yellow color of thesolution after 24hrs. In contrast, the absorbance of platinum complex in the presence of calfthymus DNA and HAS is significantly altered compared to the control experiment. The shift inthe maximum absorbance to 291nm and 290 (for complex with DNA and HAS respectively)from 272nm implies that the tetracycline ligand is in a different environment, consistent withformation of platinum – DNA and platinum-HAS complex. No precipitation occurred insolution, of platinum complex in the presence of calf thymus DNA and HSA at pH7 over 24h.