Synthesis and Molecular Dynamic Simulation of Novel Cationic and Non-cationic Pyrimidine Derivatives as Potential G-quadruplex-ligands.

BACKGROUND: Drug resistance has been a problem in cancer chemotherapy, which often causes shortterm effectiveness. Further, the literature indicates that telomere G-quadruplex could be a promising anti-cancer target. OBJECTIVE: We synthesized and characterized two new pyrimidine derivatives as ligands for G-quadruplex DNA. METHODS: The interaction of novel non-cationic and cationic pyrimidine derivatives (3a, b) with G-quadruplex DNA (1k8p and 3qsc) was explored by circular dichroism (CD) and ultraviolet-visible spectroscopy and polyacrylamide gel electrophoresis (PAGE) methods. The antiproliferative activity of desired compounds was evaluated by the MTT assay. Apoptosis induction was assessed by Propidium iodide (P.I.) staining and flow cytometry. Computational molecular modeling (CMM) and molecular dynamics simulation (MD) were studied on the complexes of 1k8p and 3qsc with the compounds. The van der Waals, electrostatic, polar solvation, solventaccessible surface area (SASA), and binding energies were calculated and analyzed. RESULTS: The experimental results confirmed that both compounds 3a and 3b interacted with 1k8p and 3qsc and exerted cytotoxic and proapoptotic effects on cancer cells. The number of hydrogen bonds and the RMSD values increased in the presence of the ligands, indicating stronger binding and suggesting increased structural dynamics. The electrostatic contribution to binding energy was higher for the cationic pyrimidine 3b, indicating more negative binding energies. CONCLUSION: Both experimental and MD results confirmed that 3b was more prone to form a complex with DNA G-quadruplex (1k8p and 3qsc), inhibit cell growth, and induce apoptosis, compared to the non-cationic pyrimidine 3a.

Preparation and characterization of novel nanostructured lipid carriers (NLC) and solid lipid nanoparticles (SLN) containing coenzyme Q10 as potent antioxidants and antityrosinase agents.

We developed novel and optimal Q10-NLC/SLN formulations as antioxidant and anti-tyrosinase agents. The formulations were analyzed for particle size, morphology, entrapment efficiency (EE %), and long-term stability. The in vitro drug release and in vivo skin penetration were evaluated using dialysis bag diffusion and Sprague Dawley (SD) rats, respectively. Cytotoxicity and protecting effects were assessed by AlamarBlue® assay, ROS level by DCFH-DA, and tyrosinase activity by l-DOPA assay, measuring the absorbance at 470 nm. The selected formulations had optimal surface characterizations, including Z-average size, PDI, and Zeta potential ranging from 125 to 207 nm, 0.09-0.22, and -7 to -24, respectively. They also exhibited physiochemical stability for up to 6 months and EE% above 80 %. The lipids ratio and co-Q10 amount as variable factors significantly affected particle size and zeta potential but were insignificant on PDI. The in vitro release diagram showed that Q10-NLC/SLN revealed a fast release during the first 8 h and prolonged release afterward. The in vivo skin permeation revealed a higher accumulative uptake of co-Q10 in the skin for Q10-NLC/SLN compared to Q10 emulsions. Both selected Q10-NLC and Q10-SLN could reduce intracellular ROS after exposure to H2O2. The Q10-NLC was found to be more potent for inhibiting the tyrosinase activity compared to O10-SLN. The results suggest that the new formulations are promising carriers for topical delivery of co-Q10 as an anti-aging and skin-whitening agent.

Preparation, Characterization, and Molecular Dynamic Simulation of Novel Coenzyme Q10 Loaded Nanostructured Lipid Carriers.

BACKGROUND: Research proved that coenzyme Q10-loaded NLC effectively removes skin wrinkles, therefore, such a formulation with good characteristics is still the research goal. OBJECTIVE: This study investigated the effect of solid lipids and surfactant type on the physical characteristics of Q10-NLC. We aimed to achieve the optimum formulation for producing NLC with long-term stability and high Entrapment efficiency (E.E.) %. We compared the experimental results with the output of the Molecular dynamic (M.D.) simulations. METHODS: To develop Q10-NLC, various solid lipids, MCT oil, and surfactants were employed. The formulations were prepared by high-shear homogenization and ultrasound methods. Stability studies were carried out 1,3, and 6 months at 4, 25, and 40°C. The optimized NLC formulations were characterized by photon correlation spectroscopy (PCS), Transmission electron microscopy (TEM), Differential scanning calorimetry (DSC), and Fourier transform infrared (FT-IR). E.E. % was determined by HPLC analysis. Atomistic M.D. simulations of two model systems were performed to gain insights into the self-assembled process of co-Q10 with other formulation components. RESULTS: Statistical analysis (Two-way ANOVA) revealed that solid lipid and surfactant factors had a significant influence on particle size, PDI, and zeta potential (***p < 0.0001). According to the results, F1 and F6 formulations had desirable surface characterizations, physicochemical stability, and high E.E. %. The atomistic M.D. simulations confirmed that the F1 system (best) was more stable than the F31 system (worst). CONCLUSION: The solid lipids: tripalmitin and compritol, stabilized with 4% tween 80 and 1% span 80, have produced stable NLC with the best surface characteristics that could be a promising formulation for the delivery of Q10. Atomistic M.D. simulation has confirmed the stability of F1 in comparison to F31.

PYRIMIDOOXADIAZINE AND TRIAZOLOPYRIMIDOOXADIAZINE DERIVATIVES: SYNTHESIS AND CYTOTOXIC EVALUATION IN HUMAN CANCER CELL LINES.

In vitro antiproliferative activities of some pyrimido[4,5-e][1,3,4]oxadiazine and [1,2,4]triazolo[4',3':1,2]pyrimido[4,5-e][1,3,4]oxadiazine derivatives were examined in human malignant cancer cell lines. All synthesized compounds inhibited the growth of malignant cells in a dose dependent manner, but among them 1,5,7-trimethyl-3-phenyl-1H-[1,2,4]triazolo[4',3':1,2]pyrimido[4,5-e][1,3,4]oxadiazine and [(1,5-dimethyl-3-phenyl-1H-[1,2,4]triazolo[4',3':1,2]pyrimido[4,5-e][1,3,4]oxadiazin-7-yl)sulfanyl]acetonitrile, both with triazole moiety, were found to be more effective than other compounds; they also induced a sub-G1 peak in the flow cytometry histogram of treated cells compared to controls, indicating that apoptotic cell death is involved in toxicity they induce. The results showed that compounds with triazole moiety fused to pyrimido[4,5-e] [1,3,4]oxadiazine derivatives are more active than those bearing chlorine or pyrrolidine groups at C-7 position.

Antitumor activity of novel pyrrolo[2,3-d]pyrimidin-4-ones.

Pyrrolo[2,3-d]pyrimidine is known to have a broad spectrum of biological activities, including antitumor activity. The cytotoxic properties of six novel pyrrolo[2,3-d]pyrimidin-4-ones in vitro were investigated on four different human cancer cell lines. Meanwhile, the role of apoptosis was explored. Malignant cells were cultured in RPMI medium and incubated with different concentrations. Cell viability was quantitated by MTT assay. Apoptotic cells were determined using DAPI (4'-6-diamidino-2-phenylindole) and propidium iodide staining of DNA fragmentation by flow cytometry (sub-G1 peak). We have identified new analogs as a novel class of antiproliferative agents by a cell-based screening method. All compounds inhibited the growth of malignant cells in a dose-dependent manner. The IC50 of compounds 4 and 5 as the two most potent analogs was determined as 122.4 and 106.7 µM in HeLa cells, respectively. Compounds 4 and 5 induced a sub-G1 peak in the flow-cytometry histogram of treated cells, compared to control, indicating that apoptotic cell death is involved in compound 4- and 5-induced toxicity. In conclusion, compounds 4 and 5 exert cytotoxic effects in different cancer cell lines in which apoptosis plays an important role. Thus, compounds 4 and 5 could be considered as potential chemotherapeutic agents.