Author : A. Salih, Huda
Primary screening for antitumor activity of Tetracycline- platinum (II) complex using Ultraviolet spectroscopy
journal of kerbala university,
Volume 11, Issue 2, Pages 90-97
In order to further clarify the molecular basis for the mechanism of action of the antitumor Pt(II) complexes, this work represent a study of the interaction of Pt(II) complex with calf thymus DNA and Human Serum Albumin (HAS) using UV-spectroscopy in vitro, this technique was used in order to gain quantitative information regarding the relative binding affinity of the platinum compounds for calf thymus DNA versus HAS.
Spectra of solution of Pt(II) complex (0.07 mM ) at pH7 was recorded at regular intervals in the absence and presence of calf thymus DNA (0.05mM) and HAS (0.16µM). The present study reveals that the UV spectrum of Cis-dicloro(tetracycline) platinum(II) complex [(Tet.)Pt Cl2] at pH7 pale yellow solution shows a maximum absorbance at 272nm and a shoulder peak at 364nm after 0.25h and 1 hr . These peaks are rapidly diminished with time due to rapid hydrolysis of the nephthacene rings to give a precipitate and loss of the pale yellow color of the solution after 24hrs. In contrast, the absorbance of platinum complex in the presence of calf thymus DNA and HAS is significantly altered compared to the control experiment. The shift in the 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 with formation of platinum – DNA and platinum-HAS complex. No precipitation occurred in solution, of platinum complex in the presence of calf thymus DNA and HSA at pH7 over 24h.