Characterization and cytotoxicity of new copper(II) silver(II) and gold(III) tetra alkyl phenoxy porphyrin derivatives

Porphyrins play a vital role in biological systems. Porphyrins and their metal complexes are used in many applications such as catalyst, dye-sensitized solar cell, photodynamic therapy, medicinal application, etc. due to their outstanding properties such as high chemical and thermal stability, strong absorption in the visible region, and flexible architectural modification. So, the development and modification of porphyrin have been dramatically studies. The series of tetraphenylporphyrin contain different meso-substituent groups (phenyl, methoxyphenyl, butyloxtphenyl, octyloxyphenyl, and dectyloxyphenyl), and their copper, silver, and gold porphyrin complexes have been successfully synthesized. Mass spectrometry, 1H NMR and 13C NMR spectroscopy, infrared spectroscopy and CHN elemental analysis were used to confirm the structure of all synthesized compounds. All free-base porphyrin and metalloporphyrin have been characterized using UV-visible, and fluorescence spectroscopy, electron paramagnetic resonance spectroscopy, cyclicvotammetry, and DFT calculation. The electronic absorption band showed a red-shift when the number of carbon atoms in the alkyl long-chain was increased. The thermal stability of synthesized compounds was studied by thermal gravimetric analysis (TGA). All of the synthesized compounds were found to be highly thermally stable over 400°C. Free-base porphyrin and their copper and silver complexes were also tested for antibacterial activity using disc diffusion technique. Their synthesized compounds were found to be effective for the inhibition of bacterial growth. In addition, the In vitro anticancer activity on breast cancer cell (SKBR3 and MCF7) of copper and gold porphyrin complexes have been investigated. Both gold and copper porphyrin complexes exhibited cytotoxicity on MCF7 cell lines. The gold(III) porphyrin complexes show better potential than copper(II) porphyrin complexes. Especially for both AuTPP and AuTOMPP show the cytotoxicity with the IC50 values of 4.30 ± 1.30 μM and 25.35 ± 7.14 μM, respectively. Moreover, the cytotoxicity of all metalloporphyrin complexes has investigated the cytotoxicity on Rhesus Monkey Kidney Epithelial Cells (LLC-MK2) representative of the human normal cells. The result shows that all metalloporphyrin complexes exhibited non-cytotoxic on LLC-MK2 cells. In the case of AuTPP shows non-cytotoxic at a concentration lower than 5 μM.