Photophysical and photochemical properties and TD-DFT calculations of novel zinc and platinum phthalocyanines

Assessing cytotoxic activities, theoretical and in silico molecular docking calculations of phthalocyanines bearing cinnamyloxy-groups

Cancer has been recognized as one of the deadliest diseases in the world in recent years. By chemically tailoring specific properties, anticancer agents can be prepared very effectively for the treatment of various cancer types. In this manner, as anticancer agents, a series of soluble metal-free and metallophthalocyanines carrying cinnamyloxy-groups at peripheral β-positions have been prepared. All synthesized phthalocyanines were characterized by various spectroscopic approaches such as ultraviolet - visible (UV - Vis), Fourier transform infrared (FT-IR), and matrix-assisted laser deionization/ionization time-of-flight mass spectroscopy (MALDI-TOF MS) techniques. These compounds are highly soluble in dimethyl sulfoxide (DMSO) and soluble in common organic solvents. The spectroscopic properties, cytotoxicity, and theoretical calculations of these complexes have been investigated. In cytotoxicity tests, compounds 1, 4, and 7 are the most active against HT-29 cell lines with IC50 values of 36.9 μM, 32.5 μM, and 51.1 μM, respectively. Also, the most and the least cytotoxic compounds against healthy CCD cell line is compounds 5 and 6 with the IC50 value of 13.4 μM and >250 μM, respectively. The PDB ID:4BQG target protein representing the HT-29 cancer cell line and the anti-cancer activities of phthalonitrile and its phthalocyanines were supported by molecular docking studies. Density Functional Theory (DFT) study supported the experimental results, including the spectral data, and implied that the compounds 5-7 are comparable by their characteristics, such as electronic properties, optical properties, electrostatic potentials, reactivity parameters, with the earlier studied compounds 2-4, which were successfully proved to be good candidates for cancer treatment.Communicated by Ramaswamy H. Sarma.

Amphiphilic tricationic Zn(II)phthalocyanine provides effective photodynamic action to eradicate broad-spectrum microorganisms

A novel tricationic Zn(II)phthalocyanine derivative, (NCH₃)₃ZnPc³⁺, was synthesized by ring expansion reaction of boron(III) [2,9(10),16(17)-trinitrosubphthalocyaninato]chloride. First, the reaction of this subphthalocyanine with 2,3-naphthalenedicarbonitrile and Zn(CH₃COO)₂ catalyzed by 8-diazabicyclo[5.4.0]undec-7-ene was used to obtain the A₃B-type nitrophthalocyanine. After reduction of nitro groups with Na₂S and exhaustive methylation of amino groups, (NCH₃)₃ZnPc³⁺ was formed in good yields. In addition, the tetracationic analog (NCH₃)₄ZnPc⁴⁺ was synthesized to compare their properties. The absorption and fluorescence spectra showed the Q-bands and the red emission, respectively, which are characteristic of the Zn(II)phthalocyanine derivatives in N,N-dimethylformamide. Furthermore, photodynamic activity sensitized by these compounds was studied in the presence of different molecular probes to sense the formation of reactive oxygen species. (NCH₃)₃ZnPc³⁺ efficiently produced singlet molecular oxygen and also it sensitized the formation of superoxide anion radical in the presence of NADH, while the photodynamic activity of (NCH₃)₄ZnPc⁴⁺ was very poor, possibly due to the partial formation of aggregates. Furthermore, the decomposition of L-tryptophan induced by (NCH₃)₃ZnPc³⁺ was mainly mediated by a type II mechanism. Antimicrobial photodynamic inactivation sensitized by these phthalocyanines was evaluated in Staphylococcus aureus, Escherichia coli, and Candida albicans, as representative microbial cells. In cell suspensions, (NCH₃)₃ZnPc³⁺ was rapidly bound to microbial cells, showing bioimages with red fluorescence emission. After 5 min of irradiation with visible light, (NCH₃)₃ZnPc³⁺ was able to completely eliminate S. aureus, E. coli and C. albicans, using 1.0, 2.5 and 5.0 μM phthalocyanine, respectively. In contrast, a low photoinactivation activity was found with (NCH₃)₄ZnPc⁴⁺ as a photosensitizer. Therefore, the amphiphilic tricationic phthalocyanine (NCH₃)₃ZnPc³⁺ is a promising photosensitizing structure for application as a broad-spectrum antimicrobial phototherapeutic agent.