Single crystal XRD, DFT investigations and molecular docking study of 2- ((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)amino)naphthalene-1,4-dione as a potential anti- cancer lead molecule.

A derivative of naphthaquinone, 2-((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)amino)naphthalene-1,4-dione (DPDHN) was synthesized from lawsone by ultrasound accelerated technique. The compound was characterized by elemental analysis, IR, UV-vis, NMR and mass spectral studies. Single crystal X-ray diffraction studies revealed that the compound crystallized in monoclinic space group P21/c. Density functional calculations of DPDHN was performed using DFT (B3LYP) method with 6-311G (5D, 7F) basis set, geometrical optimization best fit to single crystal XRD values. The charge delocalization has been analyzed using natural orbital (NBO) analysis. Effects of halogenations at ortho, meta and para positions in the title compound is discussed for frontier molecular orbital analysis, molecular electrostatic potential plots and nonlinear optical properties. It exhibited significant antioxidant property. To predict the anticancer activity of the compound, molecular docking studies were done using Schrödinger software. Molecular docking studies for DPDHN was performed on the active site of protein kinase CK2 (PDB ID: 2OXX, 1M2R and 1M2P) and to explore the estrogen receptor binding ability, the target protein with PDB ID: 3ERT and 2YLY were selected. Docking scores of the designed compound was compared with FDA approved drugs, Tamoxifen, Daunorubicin and Doxorubicin. The compound DPDHN exhibited good Glide scores for all the proteins. Glide score of DPDHN (PDB ID: 2YLY) was -9.67 kcal/mol which was as good as the currently used breast cancer drug, Tamoxifen (-10.37 kcal/mol) and found better than the drug Doxorubicin (-7.3 kcal/mol). Lead compound that satisfies predefined minimum criteria further structure and activity optimization. In the present work, hence it was further subjected to in vitro studies towards human breast cancer (MCF-7) and colon cancer (HCT-15) cell lines. The IC50 value of compound DPDHN in MCF-7 cells was 15.21 µM and that of HCT-15 was 39.21 µM which was a lower value and better than that of lawsone. Therefore DPDHN exhibited much higher toxicity towards MCF-7 cell lines. Thus, the results indicate that DPDHN is a potential anti cancer lead molecule especially for breast cancer studies.

Synthesis, spectral characterization, crystal structure, cytotoxicity and apoptosis-Inducing activity of two derivatives of 2-hydroxy-1,4-naphthaquinone.

A phenaxazone compound [5H-Benzo[a]phenoxazin-5-one (BP)] along with an aminoquinone[2-[(o-hydroxyphenyl)amino]-1,4-naphthaquinone (HAN)] derivatives were synthesized from lawsone using ultrasound irradiation technique. The structure of the compounds were characterized by elemental analysis and various spectral studies. Optoelectronic properties were studied using Schrodinger material science suit (2015). The compounds exhibit fluorescence emission in longer wave length it may find applications in photodynamic therapy. Single crystal X-ray diffraction studies reveals that the compound BP crystallizes in monoclinic space group. The antioxidant activity of HAN and BP were determined using DPPH radical scavenging assay and the results indicate that both the compounds have good antioxidant capacity, HAN having more scavenging activity than BP. Lead molecules were identified using in silico molecular docking studies as a green chemistry approach. iGEMDOCK, GOLD and Schrödinger softwares were used for these studies. The docking studies reveal that the structural modification of the parent compound gave more active compounds making them promising lead molecules. The lead molecules were subjected to in vitro studies. The cytotoxicity of BP and HAN was studied using human breast cancer (SKBR3) cell lines. The IC50 value of HAN was found to be 19.8µM while BP was found to have cell viability, less than 10% even at 25µM concentration. The chemotherapeutic agents kill the cancer cells mainly through apoptosis. HAN and BP were subjected to apoptosis studies. BP was found to more active than HAN. Thus it can be suggested that the mechanism of cell death may be through apoptosis.