Examining the Formation and Properties of TiO2 Oxide Coatings with Metals of Iron Triad

We proposed a composition of citrate-pyrophosphate electrolytes with the addition of sulfates of iron triad metals for the formation of mixed oxide systems with the varied content of dopants. The introduction of an additional ligand contributes to an increase in the stability, operation period of working solutions and to the more uniform distribution of metals-dopants. The range of voltages for the single-stage plasma-electrolytic oxidizing of titanium alloys BT1-0 and OT4-1 is 120–160 V. As a result of oxidizing, we obtained metal-oxide systems TiOx·MOy (M=Fe, Co, Ni), which, depending on the nature of a dopant, have different types of surface structures. The largest content of dopant and the minimum size of the grain are characteristic of the cobalt-containing coatings. A potential possibility of obtaining the mixed oxide systems TiOx·(FeCoNi)Oy on the alloy OT4-1 is shown. We examined the dependences of spark voltage and the rate of change in the interelectrode voltage on the concentration of dopants in electrolyte. It was established that the formed mixed oxide coatings of titanium with the iron triad metals possess significant corrosion resistance; the highest value is inherent to the systems based on cobalt. It is shown that the incorporation of iron triad metals into the composition of oxide layers leads to an increase in the degree of surface development. This ensures an increase in the catalytic activity in the reactions of carbon mono-oxide oxidation. The obtained materials of varied thickness and morphology might be used in the technological systems of catalytic purification of natural and technogenic toxicants

Rhabdastrellosides A and B: Two New Isomalabaricane Glycosides from the Marine Sponge <i>Rhabdastrella globostellata</i>, and Their Cytotoxic and Cytoprotective Effects

Investigation of the Vietnamese marine sponge Rhabdastrella globostellata led to the isolation of two new polar isomalabaricanes: rhabdastrellosides A (1) and B (2). Their structures and stereochemistry were elucidated with the application of 1D and 2D NMR, HRESIMS, and HRESIMS/MS methods, as well as chemical modifications and GC–MS analysis. Metabolites 1 and 2 are the first isomalabaricanes with non-oxidized cyclopentane ring in the tricyclic core system. Moreover, having a 3-O-disaccharide moiety in their structures, they increase a very rare group of isomalabaricane glycosides. We report here a weak cytotoxicity of 1 and 2 toward human neuroblastoma SH-SY5Y cells and normal rat H9c2 cardiomyocytes, as well as the cytoprotective activity of rhabdastrelloside B (2) at 1 µM evaluated using CoCl2-treated SH-SY5Y and H9c2 cells

New Guanidine Alkaloids Batzelladines O and P from the Marine Sponge <i>Monanchora pulchra</i> Induce Apoptosis and Autophagy in Prostate Cancer Cells

Two new guanidine alkaloids, batzelladines O (1) and P (2), were isolated from the deep-water marine sponge Monanchora pulchra. The structures of these metabolites were determined by NMR spectroscopy, mass spectrometry, and ECD. The isolated compounds exhibited cytotoxic activity in human prostate cancer cells PC3, PC3-DR, and 22Rv1 at low micromolar concentrations and inhibited colony formation and survival of the cancer cells. Batzelladines O (1) and P (2) induced apoptosis, which was detected by Western blotting as caspase-3 and PARP cleavage. Additionally, induction of pro-survival autophagy indicated as upregulation of LC3B-II and suppression of mTOR was observed in the treated cells. In line with this, the combination with autophagy inhibitor 3-methyladenine synergistically increased the cytotoxic activity of batzelladines O (1) and P (2). Both compounds were equally active in docetaxel-sensitive and docetaxel-resistant prostate cancer cells, despite exhibiting a slight p-glycoprotein substrate-like activity. In combination with docetaxel, an additive effect was observed. In conclusion, the isolated new guanidine alkaloids are promising drug candidates for the treatment of taxane-resistant prostate cancer

Anthraquinone Derivatives and Other Aromatic Compounds from Marine Fungus <i>Asteromyces cruciatus</i> KMM 4696 and Their Effects against <i>Staphylococcus aureus</i>

New anthraquinone derivatives acruciquinones A–C (1–3), together with ten known metabolites, were isolated from the obligate marine fungus Asteromyces cruciatus KMM 4696. Acruciquinone C is the first member of anthraquinone derivatives with a 6/6/5 backbone. The structures of isolated compounds were established based on NMR and MS data. The absolute stereoconfigurations of new acruciquinones A–C were determined using ECD and quantum chemical calculations (TDDFT approach). A plausible biosynthetic pathway of the novel acruciquinone C was proposed. Compounds 1–4 and 6–13 showed a significant antimicrobial effects against Staphylococcus aureus growth, and acruciquinone A (1), dendryol B (4), coniothyrinone B (7), and ω-hydroxypachybasin (9) reduced the activity of a key staphylococcal enzyme, sortase A. Moreover, the compounds, excluding 4, inhibited urease activity. We studied the effects of anthraquinones 1, 4, 7, and 9 and coniothyrinone D (6) in an in vitro model of skin infection when HaCaT keratinocytes were cocultivated with S. aureus. Anthraquinones significantly reduce the negative impact of S. aureus on the viability, migration, and proliferation of infected HaCaT keratinocytes, and acruciquinone A (1) revealed the most pronounced effect

Meroantarctines A–C, Meroterpenoids with Rearranged Skeletons from the Alga-Derived Fungus <i>Penicillium antarcticum</i> KMM 4685 with Potent p‑Glycoprotein Inhibitory Activity

New meroterpenoids, meroantarctines A–C (1–3), with unique 6/5/6/6, 6/5/6/5/6, and 6/5/6/5 polycyclic systems were isolated from the alga-derived fungus Penicillium antarcticum KMM 4685. Their structures were elucidated by spectroscopic methods, X-ray diffraction, and quantum chemical calculations. A biogenetic pathway for 1–3 was proposed. Meroantarctines A–C (1–3) inhibited p-glycoprotein activity and could resensitize drug-resistant cancer cells to docetaxel

Meroantarctines A–C, Meroterpenoids with Rearranged Skeletons from the Alga-Derived Fungus <i>Penicillium antarcticum</i> KMM 4685 with Potent p‑Glycoprotein Inhibitory Activity

New meroterpenoids, meroantarctines A–C (1–3), with unique 6/5/6/6, 6/5/6/5/6, and 6/5/6/5 polycyclic systems were isolated from the alga-derived fungus Penicillium antarcticum KMM 4685. Their structures were elucidated by spectroscopic methods, X-ray diffraction, and quantum chemical calculations. A biogenetic pathway for 1–3 was proposed. Meroantarctines A–C (1–3) inhibited p-glycoprotein activity and could resensitize drug-resistant cancer cells to docetaxel