Tripeptide linked dispiro cyclotriphosphazene conjugates: Synthesis, molecular docking analysis of compounds binding within cancer cell line receptors and in vitro cytotoxic and genotoxic activities

The novel dioxybiphenyl bridged-cyclotriphosphazenes (DPP) bearing tripeptide were synthesized and investigated for their molecular docking analysis, visualizing their binding profiles within various cancer cell line receptors and in vitro cytotoxic and genotoxic properties. The dipeptide compound (Tyr-Phe) was treated with various amino acids to obtain the tripeptide compounds (Tyr-Phe-Gly, Tyr-Phe-Ala, Tyr-Phe-Val, Tyr-Phe-Phe, and Tyr-Phe-Leu). These synthesized tripeptides were subsequently treated with DPP to obtain novel phosphazene compounds bearing tripeptide structures. As a result, the synthesis of target molecules with phosphazene compound in the center and biphenyl and tripeptide groups in the side arms was obtained for the first time in this study. Examining the cytotoxic studies in vitro of our newly synthesized compounds demonstrated the anticancer properties against four selected human cancer cell lines, including breast (MCF-7), ovarian (A2780), prostate (PC-3), and colon (Caco-2) cancer cells. The Comet Assay analysis determined that the cell death mechanism of most of the compounds with cytotoxic activity stemmed from the DNA damage mechanism. Among the compounds, the DPP-Tyr-Phe-Phe compound seems to have the best anticancer activity against the subjected cell lines (Except for A2780) with IC50 values equal to 20.18, 72.14, 12.21, and 5.17 μM against breast, ovarian, prostate, and colon cancer cell lines, respectively. For this reason, the molecular docking analysis was conducted for the DTPP compound to visualize its binding geometry and profile within the target enzyme's binding site associated with the specific cancer cell line. The analysis revealed that the DTPP derivative exhibited an optimal binding conformation and characteristics within the target enzyme's binding site, aligning well with the experimental data. Based on the data, these compounds are believed to be strong candidate molecules for both pharmaceutical and clinical applications.

Coumarin-Phosphazenes: Enhanced Photophysical Properties from Hybrid Materials

Phosphazenes have drawn a great deal of interest over the past 20 years as a potentially useful building block for the fabrication of fluorescent materials. The main objective of this work is to explore novel derivatives produced by coumarins, a class of chemicals well-known for their photophysical importance, and cyclophosphazenes. UV absorbance, fluorescence emission, quantum yield, and lifetime measurements were conducted to comprehend the optical properties. Furthermore, single-crystal X-ray analysis and theoretical calculations were carried out to confirm the structure of the molecule. The obtained findings collectively confirm the commendable optical properties exhibited by the studied compounds. Moreover, a detailed study of the crystal packing arrangement of DPP-Et-Kum-Et compound crystallized in the P21/n monoclinic space group revealed the presence of stacking interactions between the nonplanar conjugated benzene rings of the coumarins and the rigid diphenyl groups attached to the phosphazene ring. The crystal structure of the DPP-Kum-Me-Me compound is mainly based on classical C-H···O intermolecular hydrogen bonding interactions with an average distance of 2.52 Å. Importantly, the calculated absorption spectra of the compounds are in close agreement with the experimental data, further supporting their interesting electronic properties. Given that the DPP-Et-Kum-Et and DPP-Kum-Et compounds have the theoretically lowest band gaps (4.31 and 4.30 eV, respectively), the activation energies of these compounds were determined by an impedance analyzer using dc conductance values measured at different temperatures. The calculated activation energies for DPP-Et-Kum-Et and DPP-Kum-Et are 104.49 and 100.92 meV, respectively. The results demonstrate that both theoretical and experimental calculations are in agreement with each other and that the DPP-Kum-Et compound has the lowest conductivity.

Coumarin as an Elite Scaffold in Anti-Breast Cancer Drug Development: Design Strategies, Mechanistic Insights, and Structure-Activity Relationships

Breast cancer is the most common cancer among women. Currently, it poses a significant threat to the healthcare system due to the emerging resistance and toxicity of available drug candidates in clinical practice, thus generating an urgent need for the development of new potent and safer anti-breast cancer drug candidates. Coumarin (chromone-2-one) is an elite ring system widely distributed among natural products and possesses a broad range of pharmacological properties. The unique distribution and pharmacological efficacy of coumarins attract natural product hunters, resulting in the identification of numerous natural coumarins from different natural sources in the last three decades, especially those with anti-breast cancer properties. Inspired by this, numerous synthetic derivatives based on coumarins have been developed by medicinal chemists all around the globe, showing promising anti-breast cancer efficacy. This review is primarily focused on the development of coumarin-inspired anti-breast cancer agents in the last three decades, especially highlighting design strategies, mechanistic insights, and their structure-activity relationship. Natural coumarins having anti-breast cancer efficacy are also briefly highlighted. This review will act as a guideline for researchers and medicinal chemists in designing optimum coumarin-based potent and safer anti-breast cancer agents.

The first peptide derivatives of dioxybiphenyl-bridged spiro cyclotriphosphazenes: In vitro cytotoxicity activities and DNA damage studies

In this study, we aimed to synthesize new peptide-substituted cyclotriphosphazenes from a series of tyrosine-based peptides and dioxyphenyl-substituted spirocyclotriphosphazenes, and to evaluate their in vitro cytotoxicity and genotoxicity activities. Genotoxicity studies were conducted to understand whether the cytotoxic compounds cause cell death through DNA damage. The structures of the novel series of phosphazenes were characterized by FT-IR, elemental analysis, MS, 1D (³¹P, ¹H, and ¹³C-APT NMR), and 2D (HETCOR) NMR spectroscopic techniques. In vitro cytotoxic activities were carried out against human breast (MCF-7), ovarian (A2780), prostate (PC-3), colon (Caco-2) cancer cell lines and human normal epithelial cell line (MCF-10A) at different concentrations by using an MTT assay. The compounds showed considerable reductions in cell viability against all human cancer cell lines. Especially, the compounds exhibited notable effects in A2780 cell lines (p < 0.05). The IC₅₀ values of the compounds in the A2780 cell line were calculated to be 1.914 µM for TG, 20.21 µM for TV, 20.45 µM for TA, 4.643 µM for TP, 5.615 µM for BTG, 1.047 µM for BTV, 27.02 µM for BTA, 0.7734 µM for BTP, 21.5 µM for DTG, 1.65 µM for DTV, 2.89 µM for DTA and 4.599 µM for DTP. DNA damage studies of the compounds were conducted by the comet assay method using tail length, tail density, olive tail moment, head length, and head density parameters, and the results showed that the cell death occurred through DNA damage mechanism. In a nutshell, these compounds show promising cytotoxic effects and can be considered powerful candidate molecules for pharmaceutical applications.

Halogen-free layered double hydroxide-cyclotriphosphazene carboxylate flame retardants: effects of cyclotriphosphazene di, tetra and hexacarboxylate intercalation on layered double hydroxides against the combustible epoxy resin coated on wood substrates

The development of halogen-free flame retardants as environmentally friendly and renewable materials for heat and fire-resistant applications in the field of electronics is important to ensure safety measures. In this regard, we have proposed a simple and halogen-free strategy for the synthesis of flame retardant LDH-PN materials to decrease the fire hazards of epoxy resin (EP), via a co-precipitation reaction between Mg(NO₃)₂ and Al(NO₃)₃ and the subsequent incorporation of different cyclotriphosphazene (PN) carboxylate anions. The cyclotriphosphazene-based di, tetra and hexacarboxylate-intercalated layered double hydroxides are designated as LDH-PN-DC, LDH-PN-TC and LDH-PN-HC, respectively. Furthermore, the intercalation of cyclotriphosphazene carboxylate anions into the LDH layers was confirmed by PXRD, FT-IR, TGA, solid-state ³¹P NMR, nitrogen adsorption and desorption analysis (BET), HR-SEM and XPS. Evaluation of the flame retardant (vertical burning test and limiting oxygen index) properties was demonstrated by formulating the LDH-PN materials with epoxy resin (EP) in different ratios coated on wood substrates to achieve the desired behaviour of the EP/LDH-PN composites. Structure–property analysis reveals that EP/LDH-PN-TC-20 wt% and EP/LDH-PN-HC-20 wt% achieved a V₀ rating in the UL-94 V test and achieved higher LOI values (27.7 vol% for EP/LDH-PN-TC-20 wt% and 29 vol% for EP/LDH-PN-HC-20 wt%) compared to the epoxy-coated wood substrate (23.2 vol%), whereas EP/LDH-PN-DC failed in the vertical burning test for various weight percentages of LDH-PN-DC from 5 wt% to 20 wt% in the composites, with a lower LOI value of 22.1 vol%. Excellent flame retardancy was observed for EP/LDH-PN-TC and EP/LDH-PN-HC due to the presence of more binding sites of carboxylate anions in the LDH layers and less or no spiro groups in cyclotriphosphazene compared to that in EP/LDH-PN-DC. In addition, the synergistic flame retardant effect of the combination of LDH and cyclotriphosphazene on the epoxy resin composites remains very effective in creating a non-volatile protective film on the surface of the wood substrate to shelter it from air, absorb the heat and increase the ignition time, which prevents the supply of oxygen during the combustion process. The results of this study show that the proposed strategy for designing flame-retardant properties represents the state-of-the-art, competent coating of inorganic materials for the protection and functionalization of wood substrates.

The flame retardant properties of the different types of cyclotriphosphazene carboxylate-intercalated LDH materials are emphasized by increasing the number of binding sites and decreasing the number of spiro groups in the cyclotriphosphazene core.

Cyclotriphosphazene-Based "Butterfly" Fluorescence Probe for Lysosome Targeting

A cyclotriphosphazene-based "butterfly" fluorescence probe HCCP-MNI bearing two naphthalimide and morpholine units were developed for lysosome targeting. The synthesized HCCP-MNI exhibited stable fluorescence signals and was cytocompatible in the given concentration range. Co-localization experimental results showed that cells treated with the HCCP-MNI and a commercial dye (Lyso-Tracker Red DND-99) had overlapped fluorescence signals, demonstrating its targeting specificity to lysosomes. The developed HCCP-MNI may be used for cell tracking applications associated with the functionalities of lysosomes.

Synthesis and spectroscopic characterizations of hexakis[(1-(4'-oxyphenyl)-3-(substituted-phenyl)prop-2-en-1-one)]cyclotriphosphazenes: their in vitro cytotoxic activity, theoretical analysis and molecular docking studies

The hexachlorocyclotriphosphaze compound (N₃P₃Cl₆, HCCP) was reacted with excess (E)-(1-(4'-oxyphenyl)-3-(substituted-phenyl)prop-2-en-1-ones (2-11) to produce hexakis[(1-(4-oxyphenyl)-3-(substituted-phenyl)prop-2-en-1-one)]cyclotriphosphazenes (CP 2-11). The structures of products (CP 2-11) were confirmed using elemental analysis, FT-IR, MS spectral analysis as well as ³¹P, ¹H and ¹³C-APT NMR techniques and their thermal properties determined by TGA and DSC techniques. The HOMO-LUMO energy gap and chemical reactivity identifiers were calculated and HOMO and LUMO images were viewed. According to the calculations, all the chemical potential values of CP 2-11 are negative and it shown that the molecules are stable. The in vitro cytotoxic of CP 2-11 investigated and their activity potentials were evaluated by molecular docking studies with Autodock Vina softwares. CP 2-11 compounds were found to demonstrate cytotoxic activity against human cancer cell lines (A2780, LNCaP and PC-3). The CP 2-11 compounds reduced the cell viability against all cancer cell lines in the range 36%-90% especially. The results showed that these compounds are powerful candidate molecules for pharmaceutical applications.