Hybrids of 1,4-Naphthoquinone with Thymidine Derivatives: Synthesis, Anticancer Activity, and Molecular Docking Study.

One of the most essential health problems is cancer, the first or second cause of death worldwide. Head and neck cancers are hard to detect due to non-specific symptoms. The treatment often relies on a combination of radio and chemotherapy. For this reason, the research of new anticancer compounds is fundamental. The natural and synthetic compounds with 1,4-naphthoquinone scaffold is characterized by high anticancer activity. The study aimed to evaluate the synthesis and anticancer activity of hybrids 1,4-naphthoquinone with thymidine derivatives. The series of compounds allows us to check the influence of the substituent in the C3' position of the thymidine moiety on the cytotoxicity against squamous cancer cell lines (SCC-9 and SCC-25) and submandibular gland cancer (A-253). An annexin V/propidium iodide (PI) co-staining assay shows that derivatives cause the apoptotic in SCC-25 and A-253 cell lines. The molecular docking study examined the interaction between the active site of the BCL-2 protein and the hybrids.

New Propargyloxy Derivatives of Galangin, Kaempferol and Fisetin-Synthesis, Spectroscopic Analysis and In Vitro Anticancer Activity on Head and Neck Cancer Cells.

Head and neck cancer (HNC) therapy is limited; therefore, new solutions are increasingly being sought among flavonoids, which exhibit numerous biological properties, including potential anticancer activity. However, because they are mostly insoluble in water, are unstable and have low bioavailability, they are subjected to chemical modification to obtain new derivatives with better properties. This study aimed to synthesize and analyze new propargyloxy derivatives of galangin, kaempferol and fisetin, and to evaluate their anticancer activity against selected HNC cell lines. The obtained derivatives were assessed by spectroscopic analysis; next, their anticancer activity was evaluated using a flow cytometer and real-time cell analysis. The results showed that only the fisetin derivative was suitable for further analysis, due to the lack of crystal formation of the compound. The fisetin derivative statistically significantly increases the number of cells in the G2/M phase (p < 0.05) and increases cyclin B1 levels. A statistically significant increase in the number of apoptotic cells after being exposed to the tested compound was also observed (p < 0.05). The data indicate that the obtained fisetin derivative exhibits anticancer activity by affecting the cell cycle and increasing apoptosis in selected HNC lines, which suggests its potential use as a new medicinal agent in the future.

Hybrids of 1,4-Quinone with Quinoline Derivatives: Synthesis, Biological Activity, and Molecular Docking with DT-Diaphorase (NQO1).

Hybrids 1,4-quinone with quinoline were obtained by connecting two active structures through an oxygen atom. This strategy allows to obtain new compounds with a high biological activity and suitable bioavailability. Newly synthesized compounds were characterized by various spectroscopic methods. The enzymatic assay used showed that these compounds were a suitable DT-diaphorase (NQO1) substrates as evidenced by increasing enzymatic conversion rates relative to that of streptonigrin. Hybrids were tested in vitro against a panel of human cell lines including melanoma, breast, and lung cancers. They showed also a high cytotoxic activity depending on the type of 1,4-quinone moiety and the applied tumor cell lines. It was found that cytotoxic activity of the studied hybrids was increasing against the cell lines with higher NQO1 protein level, such as breast (MCF-7 and T47D) and lung (A549) cancers. Selected hybrids were tested for the transcriptional activity of the gene encoding a proliferation marker (H3 histone), cell cycle regulators (p53 and p21) and the apoptosis pathway (BCL-2 and BAX). The molecular docking was used to examine the probable interaction between the hybrids and NQO1 protein.

Molecular Structure, In Vitro Anticancer Study and Molecular Docking of New Phosphate Derivatives of Betulin.

A series of 30-diethylphosphate derivatives of betulin were synthesized and evaluated for their in vitro cytotoxic activity against human cancer cell lines, such as amelanotic melanoma (C-32), glioblastoma (SNB-19), and two lines of breast cancer (T47D, MDA-MB-231). The molecular structure and activities of the new compounds were also compared with their 29-phosphonate analogs. Compounds 7a and 7b showed the highest activity against C-32 and SNB-19 cell lines. The IC50 values for 7a were 2.15 and 0.91 µM, and, for 7b, they were 0.76 and 0.8 µM for the C-32 and SNB-19 lines, respectively. The most potent compounds, 7a and 7b, were tested for their effects on markers of apoptosis, such as H3, TP53, BAX, and BCL-2. For the whole series of phosphate derivatives, a lipophilicity study was performed, and the ADME parameters were calculated. The most active products were docked to the active site of the EGFR protein. The relative binding affinity of selected phosphate betulin derivatives toward EGFR was compared with standard erlotinib on the basis of ChemScore and KDEEP score. Positively, all derivatives docked inside the cavity and showed significant interactions. Moreover, a molecular dynamics study also reveals that ligands 7a,b form stable complexes and the plateau phase started after 7 ns.

Design, synthesis and biological activity of 1,4-quinone moiety attached to betulin derivatives as potent DT-diaphorase substrate.

In this research, betulin derivatives were bonded to the 1,4-quinone fragment by triazole linker. Furthermore, the enzymatic assay used has shown that these compounds are a good DT-diaphorase (NQO1) substrates as evidenced by increasing enzymatic conversion rates relative to that of streptonigrin. The anticancer activities of the hybrids were tested against a panel of human cell lines, like: melanoma, ovarian, breast, colon, and lung cancers. The structure-activity relationship showed that the activity depends on the type of 1,4-quinone moiety and the tumor cell lines used. It was also found that the anticancer effects were increasing against the cell line with higher NQO1 protein level, like: breast (T47D, MCF-7), colon (Caco-2), and lung (A549) cancers. The transcriptional activity of the gene encoding a proliferation marker (H3 histone), cell cycle regulators (p53 and p21) and apoptosis pathway (BCL-2 and BAX) for selected compounds were determined. The molecular docking study was carried out to examine the interaction between the hybrids and NQO1 enzyme. The computational simulation showed that the type of the 1,4-quinone moiety influences location of the compound in the active site of the enzyme. It is worth noting that the study of new hybrids of betulin as substrate for NQO1 protein may lead to new medical therapeutic applications in the future.

Application of TLC to Evaluate the Lipophilicity of Newly Synthesized Betulin Derivatives.

Designing a new drug has recently become a very important topic that many researches are concerned with. This work relates to a newly synthesized betulin and betulone derivatives which have anticancer activity. Thin-layer chromatography was applied to evaluate the lipophilicity of these triterpenes in order to find the correlation between theoretically and experimentally calculated values of lipophilicity and the structure of compounds investigated. Moreover, the relationships between lipophilicity and pharmacokinetic parameters or anticancer activity were carried out. The similarity analysis was also done for the purpose to divide the compounds investigated into groups pointing which of these can meet the criteria for medicine substances. The cluster analysis showed the differences in the compounds grouping in relation which the values of lipophilicity are considered, i.e., calculated by computer software or obtained experimentally by use of TLC. Analysis clearly shows that those theoretically calculated values of lipophilicity are strongly connected to the structure of the compounds.

Structural and spectral characterisation of 2-amino-2H-[1,2,3]triazolo[4,5-g]quinoline-4,9-dione polymorphs. Cytotoxic activity and molecular docking study with NQO1 enzyme.

Depending on temperature, the 2-amino-2H-[1,2,3]triazolo[4,5-g]quinoline-4,9-dione forms two polymorphic structures, which differ in the spatial arrangement of the amine group. Both polymorphs were investigated using different experimental methods as well as various quantum chemical calculations in order to characterise their molecular structures. We used X-ray diffraction, FT-IR and NMR (solid-state and liquid) methods supplemented by the density functional theory (DFT) calculations, molecular electrostatic potential (MEP) and molecular orbital (HOMO, LUMO) analyses. It was found that the arrangement of the amine group affected the crystal structure, formation of H-bonds, the amine and carbonyl vibration bands in the FT-IR spectra, chemical shift of amine group in 15N CP/MAS NMR and chemical shift of amine protons in 1H NMR spectra. Both polymorphs were tested on anticancer activity against a panel of human cancer cell lines. Comparing the activity of both compounds showed that activity against MCF-7, MDA-MB-231 and Caco-2 lines depend on the arrangement of the amine group. Moreover, both polymorphs exhibited the highest activity against cell line with high NQO1 protein level, such as: A549, MCF-7 and Caco-2. The molecular docking was used to examine the probable interaction between the ligand of the tested polymorphs and the NQO1 enzyme. The analysis showed that ligands formed a hydrophobic interaction with tryptophan (Trp105), phenylalanine (Phe126 and Phe178) and tyrosine (Tyr 126).

5,8-Quinolinedione Scaffold as a Promising Moiety of Bioactive Agents.

Natural 5,8-quinolinedione antibiotics exhibit a broad spectrum of activities including anticancer, antibacterial, antifungal, and antimalarial activities. The structure-activity research showed that the 5,8-quinolinedione scaffold is responsible for its biological effect. The subject of this review report is a presentation of the pharmacological activity of synthetic 5,8-quinolinedione compounds containing different groups at C-6 and/or C-7 positions. The relationship between the activity and the mechanism of action is included if these data have been included in the original literature. The review mostly covers the period between 2000 and 2019. Previously published literature data were used to present historical points.

Betulin-1,4-quinone hybrids: Synthesis, anticancer activity and molecular docking study with NQO1 enzyme.

Betulin-1,4-quinone hybrids were obtain by connecting two active structures with a linker. This strategy allows for obtaining compounds showing a high biological activity and better bioavailability. In this research, synthesis, anticancer activity and molecular docking study of betulin-1,4-quinone hybrids are presented. Newly synthesized compounds were characterized by 1H, 13C NMR, IR and HR-MS. Hybrids were tested in vitro against a panel of human cell lines including glioblastoma, melanoma, breast and lung cancer. They showed a high cytotoxic activity depending on the type of 1,4-quinone moiety and the applied tumor cell lines. It was found that cytotoxic activities of the studied hybrids were increasing against the cell line with higher NQO1 protein level, like melanoma (C-32), breast (MCF-7) and lung (A-549) cancer. Selected hybrids were tested on the transcriptional activity of the gene encoding a proliferation marker (H3 histone), a cell cycle regulators (p53 and p21) and an apoptosis pathway (BCL-2 and BAX). The obtained results suggested that the tested compounds caused a mitochondrial apoptosis pathway in A549 and MCF-7 cell lines. The molecular docking was used to examine the probable interaction between the hybrids and human NAD[P]H-quinone oxidoreductase (NQO1) protein. The computational studies showed that the type of the 1,4-quinone moiety affected the location of the compound in the active site of the enzyme. Moreover, it was shown that an interaction of 1,4-quinone fragment with the hydrophobic matrix of the active site near Tyr128, Phe178, Trp105 and FAD cofactor could explain the observed increase of TP53 gene expression.

New phosphate derivatives of betulin as anticancer agents: Synthesis, crystal structure, and molecular docking study.

Betulin derivatives exhibit an antiproliferative activity and have been tested for many cancer cell lines. This paper describes a new series of 3-phosphate derivatives of betulin bearing different substituents at C28 position. The synthesized compounds were tested in vitro for their antiproliferative effect against human leukemia (MV-4-11 and CCRF/CEM), lung carcinoma (A549), prostate cancer (DU 145), melanoma (Hs 294T) cell lines, and murine leukemia P388. To explore the possible mechanism of anticancer activity for the most in vitro active compounds (4, 5, 7 and 8) and betulin, molecular docking was performed to the binding sites of potential anticancer targets, described for the various triterpene derivatives, including topoisomerase I and II, epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGFR), transcription factor NF-κB, anti-apoptotic protein Bcl-2 and peroxisome proliferator-activated receptor (PPARγ). According to the results of the docking, the best fit to the binding pocket of PPARγ was shown by compound 4.

Biological Activity and In Silico Study of 3-Modified Derivatives of Betulin and Betulinic Aldehyde.

A series of 3-substituted derivatives of betulin and betulinic aldehyde were synthesized as promising anticancer agents. The newly triterpenes were tested against five human cancer cell lines like biphenotypic B myelomonocytic leukaemia (MV-4-11), adenocarcinoma (A549), prostate (Du-145), melanoma (Hs294T), breast adenocarcinoma (MCF-7) and normal human mammary gland (MCF-10A). The compound 9 showed towards Du-145, MCF-7 and Hs294T cells significant antiproliferative activity with IC50 ranging from 7.3 to 10.6 µM. The evaluation of ADME properties of all compounds also includes their pharmacokinetic profile. The calculated TPSA values for synthetized derivatives are in the range between 43.38 Ų and 55.77 Ų suggesting high oral bioavailability. The molecular docking calculations showed that triterpene 9 fits the active site of the serine/threonine protein kinase Akt.

Endogenous fluorescence can differentiate the keratoconic cornea.

The purpose of the study was to investigate the endogenous fluorescence of the keratoconic cornea in order to analyze changes in the spectra due to the keratoconic stroma abnormalities. Twenty-two corneal buttons obtained from patients with keratoconus (KC, N = 22) at the time of penetrating keratoplasty were used. As a reference, twelve normal corneas (N = 12): ten from the Eye Bank and two from enucleated eyes due to choroidal melanoma were used. The fluorescence excitation/emission matrices (EEM) in the ranges of 250-400/260-600 nm were recorded. Healthy cornea, keratoconic cornea and sclera showed three main EEM bands, which correspond to the following fluorophores: tryptophan residues in the proteoglycan fraction of corneal/scleral stromas, naturally occurring collagen cross-links and the NAD(P)H fraction present in the metabolically active cells. Relative intensity factors S1, S2 and S3 describing the contribution of each kind of fluorophore to the total fluorescence of the tissue were calculated. Normal and keratoconic corneas show qualitatively similar fluorescence matrices, but the statistically significant differences in the mean values of the S1, S2 and S3 parameters for the KC and normal corneas were observed indicating changes in contribution of different fluorophores to the whole fluorescence of the tissue. Moreover, differences between multidimensional distribution of the relative intensity factors S1, S2 and S3 between these groups were demonstrated (p < 0.001). In conclusions: Differences in the relative intensity factors calculated on a basis of the fluorescence spectra can correspond to the changes found in the KC stroma regarding natural collagen cross-links and the proteoglycan fraction. These parameters well differentiate the KC and normal corneas that could serve as an additional tool for the keratoconus characterization.

Novel triazoles of 3-acetylbetulin and betulone as anticancer agents.

The CuAAC reaction of azides and acetylenic triterpenes was used for synthesis of new triazoles of 3-acetylbetulin and betulone. The triazole derivatives were evaluated for their anticancer activity in vitro against amelanotic melanoma C-32, ductal carcinoma T47D and glioblastoma SNB-19 cell lines. 28-[1-(3'-Deoxythymidine-5'-yl)-1H-1,2,3-triazol-4-yl]carbonylbetulone 6e exhibited a significant IC50 value (0.17 µM) against the human glioblastoma SNB-19 cell line, an almost 5-fold higher potency while compared with reference cisplatin.

Novel Triazole Hybrids of Betulin: Synthesis and Biological Activity Profile.

Betulin derivatives containing a 1,2,3-triazole ring possess a wide spectrum of biological activities, including antiviral, anticancer, and antibacterial activity. A series of novel triazoles were prepared by the 1,3-dipolar cycloaddition reaction between the alkyne derivatives of betulin and organic azides. The chemical structures of the obtained compounds were defined by ¹H and 13C NMR, IR, and high-resolution mass spectrometry (HR-MS) analysis. The target triazoles were screened for their antiviral activity against DNA and RNA viruses. The cytotoxic activity of the obtained compounds 5a-k and 6a-h was determined using five human cancer cell lines (T47D, MCF-7, SNB-19, Colo-829, and C-32) by a WST-1 assay. The bistriazole 6b displayed a promising IC50 value (0.05 µM) against the human ductal carcinoma T47D (500-fold higher potency than cisplatin). The microdilution method was applied for an evaluation of the antimicrobial activity of all of the compounds. The triazole 5e containing a 3'-deoxythymidine-5'-yl moiety exhibited antibacterial activity against two gram-negative bacteria vz. Klebsiellapneumoniae and Escherichia coli (minimal inhibitory concentration (MIC) range of 0.95-1.95 µM).

Alkoxy and Enediyne Derivatives Containing 1,4-Benzoquinone Subunits-Synthesis and Antitumor Activity.

The compounds produced by a living organism are most commonly as medicinal agents and starting materials for the preparation of new semi-synthetic derivatives. One of the largest groups of natural compounds consists of products containing a 1,4-benzoquinone subunit. This fragment occurs in three enediyne antibiotics, dynemicin A, deoxydynemicin A, and uncilamicin, which exhibit high biological activity. A series of alkoxy derivatives containing 1,4-naphthoquinone, 5,8-quinolinedione, and 2-methyl-5,8-quinolinedione moieties was synthesized. Moreover, the 1,4-benzoquinone subunit was contacted with an enediyne fragment. All obtained compounds were characterized by spectroscopy and spectrometry methods. The resulting alkane, alkene, alkyne and enediyne derivatives were tested as antitumor agents. They showed high cytotoxic activity depending on the type of 1,4-benzoquinone subunit and the employed tumor cell lines. The synthesized derivatives fulfill the Lipinski Rule of Five and have low permeability through the blood-brain barrier.

New acetylenic derivatives of betulin and betulone, synthesis and cytotoxic activity.

Betulin 1 and its semisynthetic derivatives exhibit a cytotoxic activity toward various cancer cell lines. These compounds are a promising and potential anticancer candidates. A series of betulin derivatives was prepared and tested for the antiproliferative activity in vitro against T47D breast cancer, CCRF/CEM leukemia, HL-60 promyelocytic leukemia, SW707 colorectal, murine P388 leukemia, as well as BALB3T3 normal fibroblasts cell lines. Cisplatin and betulin 1 were used as a reference compounds. Some derivatives of betulin showed a higher cytotoxic activity than the parent compound 1. Two derivatives (5 and 17) were 24-fold potent than betulin 1 against the human promyelocytic leukemia cell line (HL-60), with an IC50 value of 0.3 µg/mL.

Alkynyloxy derivatives of 5,8-quinolinedione: Synthesis, in vitro cytotoxicity studies and computational molecular modeling with NAD(P)H:Quinone oxidoreductase 1.

The natural 7-amino-5,8-quinolinodione antibiotics were the substrate for the NQO1 protein. The structure-activity relationship showed that the 5,8-quinolinedione moiety was responsible for the interaction with the enzyme. In our research, we presented the synthesis, cytotoxic activity and theoretical study of a 5,8-quinolinedione compound as a potential inhibitor of the NQO1 enzyme. Mono and disubstituted alkynyloxy derivatives of the 5,8-quinolinedione were synthesized and characterized by 1H, 13C NMR, IR and HR-MS spectra. Newly synthesized derivatives were also tested for their biological activity in vitro against the human cancer cell lines. They showed high cytotoxic activity depending on the type of substituent and the employed tumor cell lines. Moreover, two breast cancer cell lines, MDA-MB-231 and MCF-7, were chosen for analysis as they are characterized by different NQO1 protein levels. It was found that cytotoxic activities of all studied compounds increased against the cell line with a higher NQO1 protein level. The molecular docking was used to examine the probable interaction between the molecules of alkynyloxy derivatives and human NAD[P]H-quinone oxidoreductase (NQO1) protein. The computational studies showed that the 5,8-quinolinedione moiety of all docked compounds was located deeply in the hydrophobic matrix of the active site near the side chains of aromatic residues in positions Trp 105, Phe 178, Tyr 126 and Tyr 128. In every case, introduction of aromatic moieties into the 5,8-quinolinedione molecule led to an increase in the binding affinity in relation to the 6,7-dichloro-5,8-quinolinedione.

Betulin Phosphonates; Synthesis, Structure, and Cytotoxic Activity.

Betulin derivatives are a widely studied group of compounds of natural origin due to their wide spectrum of biological activities. This paper describes new betulin derivatives, containing a phosphonate group. The allyl-vinyl isomerization and synthesis of acetylenic derivatives have been reported. Structural identification of products as E and Z isomers has been carried out using ¹H-, (13)C-, (31)P-NMR, and crystallographic analysis. The crystal structure in the orthorhombic space group and analysis of crystal packing contacts for 29-diethoxyphosphoryl-28-cyclopropylpropynoyloxy-lup-20E(29)-en-3ß-ol 8a are reported. All new compounds were tested in vitro for their antiproliferative activity against human T47D (breast cancer), SNB-19 (glioblastoma), and C32 (melanoma) cell lines.