Hemoglobin degradation in parasitic acidic vacuole represents a major metabolic pathway, which is essential for the intraerythrocytic development of malaria parasites. Four members of a family of P. falciparum aspartic proteinases, termed as digestive plasmepsins (PMI, PMII, PMIV and HAP) have shown to be able to degrade hemoglobin in vitro¹. These enzymes have been identified as potential anti-malarial drug targets and their inhibition has been demonstrated to result in parasites death^2,3. The aim of this study was design and molecular docking analysis of 15 novel 9-aminoacridine derivatives with potential antimalarial activity, based on inhibition of plasmepsins I and II. Interactions of 9-aminoacridine derivatives with plasmepsins were analyzed in AutoDock Vina program. Crystal structures of selected targets (PMI and PMII) were obtained from the Protein Data Bank (PDB ID 3QS1 and 2IGY).

Derivatives with binding energies similar to the corresponding co-crystallized ligand KNI-10006 and which form some of the key binding interactions with PMI were 1 (N'-(acridin-9-yl)benzohydrazide), 6 (2-hydroxy-N'-(3-(trifluoromethyl)acridin-9-yl)benzohydrazide), 7 (N'-(3-(trifluoromethyl)acridin-9-yl)benzohydrazide), 8 (N-benzyl-3-(trifluoromethyl)acridin-9-amine), 10 (N-phenethyl-3-(trifluoromethyl)acridin-9-amine) and 15 (N-(3,4-dichlorophenyl)acridin-9-amine). Derivative 15 forms seven key binding interactions (Leu291, Val76, Thr218, Ile300, Asp215, Asp32 and Tyr75) with PMI, although its binding energies were slightly higher in comparison to KNI-10006. On the other hand, derivatives 1, 2 (N'-(acridin-9-yl)-2-hydroxybenzohydrazide), 6, 7 and 8 form some of the key binding interactions towards PMII with higher binding energies compared to the co-crystallized ligand. Derivative 2 forms five key binding interactions (Phe111, Ile32, Trp41, Ile123 and Met75) with PMII.

One of the actual problems of modern pharmacy is the creation of complex drugs and dietary supplements based on Hypericum maculatum L., which have anti-inflammatory, astringent, antispasmodic, and tonic effects.

Hypericum herb contains a complex of biologically active substances of different polarity: flavonoids (hyperoside, rutin, quercetin up to 7%), hypericin (up to 0.4%), pigments (anthocyanins), tannins (8-10%), water-soluble vitamins, choline , saponins, carotenoids (about 50 mg %), essential oil (up to 3%).

A rational plant materials use requires the development of modern technologies of the extraction process, ensuring maximum yield of biologically active substances.

One of these methods is a biphasic extraction solvents system of different polarities, such as a water-alcohol solution and vegetable oil.

This method allows, by one cycle, to simultaneously obtain two extracts, alcohol and oil, containing a complex of various hydrophilic and lipophilic compounds.

The dependence of the ratio of the polar and non-polar phases on the biologically active substances extraction from the Hypericum herb was studied.

The effectiveness of two-phase extraction was determined by the content of flavonoids in the water-alcohol phases (X%, in terms of rutin) and carotenoids in oil phases (mg%).

It was determined that a two-phase solvent system extracts a complex of biologically active substances of Hypericum maculatum L. more effectively than a sequential extraction with separate solvents of different polarities.

The polar phase enhances the processes of desorption, diffusion and phase transfer of not only hydrophilic, but also lipophilic Hypericum herb substances.

The optimal ratio of raw materials: 70% ethanol: oil, which provided the maximum yield of flavonoids and carotenoids from raw materials, was 1:10:10.

The aim of this study is to obtain, qualitative and semi-quantitative analysis of essential oil of black pepper (Piper nigrum L.) from various geographic origins. By comparing the obtained residues, it will determine whether and to what extent the origin affects the qualitative and quantitative composition of the individual components of the black pepper oil. Samples with a declaration of origin from Brazil, Vietnam, Poland and Indonesia were purchased at local stores. The essential oil was isolated by the method of distillation with water vapor from crushed fruits of black pepper. The qualitative and semi-quantitative analysis of the oil was performed by the method of gas chromatography coupled to mass spectrometry (GC-MS). A total of 26 components were identified. Essential oils of Piper nigrum from Brazil, Vietnam contained more monoterpenes and less sesquiterpenes and oxygenated terpenoids as compared to essential oil of Piper nigrum from Poland and Indonesia. GC-MS analysis in all tested samples identified α- and β-pinene, limonene, α- and β-caryophyllene, where β is the caryophyllene compound with the highest percentage distribution (24.51-41.9%). Essential oil of pepper fruits originating from Vietnam and Indonesia contained 3-carene with a representation of 23.13% and 17.25% respectively. The presence of this compound is minimal in oil obtained from pepper originating from Brazil (2.61%) and in the oil originating from Poland, its presence has not been confirmed. β-terpinene, α-copaene and cadinene are not identified in pepper oil from Indonesia while their presence is confirmed in other oils (1.16-6.45%). The qualitative composition of pepper oil, as well as the relative representation of individual components of the oil largely depends on the geographical origin of the drug. Differences in the qualitative and quantitative composition of essential oils of pepper can potentially be reflecedt on the manifestation of the biological effects of the oil. The presence of active compounds such as caryophyllene, 3-carene, limonene and pinene place this oil as an important part of modern medicine.

Antimicrobial peptides (AMPs) have been identified as a potentially new class of antibiotics. There is a lot of computational methods of AMP prediction. Although most of them can predict antimicrobial potency against any microbe (microbe is not identified) with rather high accuracy, prediction quality of these tools against particular bacterial strains is low (Bioinformatics, 2018, in press; Journal of Chemical Information and Modeling 58, 1141-1151). Special prediction is a tool for the prediction of antimicrobial potency of peptides against particular target species with high accuracy. This tool is included into the Database of Antimicrobial Activity and Structure of Peptides (DBAASP, https://dbaasp.org, Nucleic acids research 44 (D1), D1104-D1112). In this presentation we describe this tool and predictive models for some Gram+ bacterial strains (Staphylococcus aureus ATCC 25923 and Bacillus subtilis) and a model for the prediction of hemolytic activity. Predictive model for Gram- Escherichia coli ATCC 25922 was presented earlier (Journal of Chemical Information and Modeling 58, 1141-1151, In 2nd Int. Electron. Conf. Med. Chem. 01-30 November 2016; Sciforum, 2016, A031). Special prediction tool can be used for the design of peptides being active against particular strain. To demonstrate the capability of the tool, peptides predicted as active against E. coli ATCC 25922 and S. aureus ATCC 25923 have been synthesized, and tested in vitro. The results have shown the justification of using special prediction tool for the design of new AMPs.

Cyclooxygenase enzymes (COX-1 and COX-2) are bifunctional homodimeric enzymes which catalyze the biological oxidation of arachidonic acid and biosynthesis of the proinflammatory prostaglandins, such as PGD₂, PGE₂, PGF_2α and PGI₂. COX-1 isoform is a constitutive form distributed in most tissues where it performs mostly physiological functions of the gastrointestinal organs, the kidneys, and platelets. The enzyme COX-2 is an inducible form, expressed during inflammation and with only minor physiological functions like stimulating prostacyclin (PGI₂) production and thus preventing platelet aggregation. Both of these enzymes (COX-1 and COX-2) convert arachidonic acid into prostaglandin, which leads to pain and inflammation^1,2.

The design of selective cyclooxygenase inhibitors has been of great interest over the past few years due to side effects associated with existing nonsteroidal anti-inflammatory drugs (NSAIDs) that inhibit both COX-1 and COX-2. This study aims to investigate the molecular docking of S-alkyl derivatives of thiosalicylic acid (S-benzyl, S-methyl, S-ethyl, S-propyl and S-butyl) towards COX-1 and COX-2 enzymes. Molecular docking studies were performed in order to explain the possible interactions between the inhibitors and both COX isoforms binding pockets. The docking studies were analysed with AutoDock Vina program. The crystal structures of the enzymes (COX-1 and COX-2), complexed with co-crystallized ligands, were obtained from Protein Data Bank (PDB ID: 1HT5 and 4FM5).

COX-1 and COX-2 enzymes have very similar amino acid sequences. The ligand binding analysis in the active site of COX-1 showed that S-benzyl, S-propyl and S-butyl derivatives of thiosalicylic acid possess the best interactions. S-butyl derivative of thiosalicylic acid shows unique binding mode and forms five key binding interactions (Ala527, Leu352, Ser530, Val349 and Tyr355) with active site of COX-1. S-benzyl, S-ethyl, S-propyl and S-butyl derivatives of thiosalicylic acid possess some of the key binding interactions with the active site of COX-2. The docking results indicated that S-butyl derivative of thiosalicylic acid shows the key binding interactions (Leu352, Ser530, Val349, Tyr355, Ala527 and Gly526) with selected target. Binding energies of all tested compounds were similar to the corresponding co-crystallized ligands for both targets (COX-1 and COX-2).

References:

1. Fitzpatrick FA. Cyclooxygenase enzymes: regulation and function. Curr Pharm Des. 2004; 10(6): 577-88.
2. Rao P, Knaus EE. Evolution of nonsteroidal anti-inflammatory drugs (NSAIDs): cyclooxygenase (COX) inhibition and beyond. J Pharm Pharm Sci. 2008; 11(2): 81-110.

Chagas’ disease is an infection caused by the protozoan Trypanosoma cruzi that represents a major public health threat in Latin America. The development of new drugs against T. cruzi is still required since the only two drugs (nifurtimox and benznidazole) currently used cause severe side effects. Previously we developed 4-carbohydrazide derivatives of 1H-pyrazolo[3,4-b]pyridine as antichagasic agents, which the hit compound was the N’-4-hydroxybenzylidene-carbohydrazide derivative. In order to verify the influence of the substituent position and the carbohydrazide moiety replacement for 1,3,4-oxadiazoline moiety, herein we described the synthesis and in vitro evaluation of trypanocidal activity and cytotoxicity of eleven new 1,6-diphenyl-4-(substituted)-1H-pyrazolo[3,4-b]pyridine derivatives. New N’-hydroxybenzylidene-carbohydrazide derivatives were synthesized by reaction of 4-carbohydrazide-1,6-diphenyl-3-methyl-1H-pyrazolo[3,4-b]pyridine with the corresponding substituted benzaldehyde (2-OH; 3-OH; 3,4-OH; 3-OH-4-OCH₃). The 1,3,4-oxadiazoline derivatives were synthetized from the corresponding hydroxybenzylidene-carbohydrazide compounds by treatment with refluxing acetic anhydride. The new derivatives containing the 1,3,4-oxadiazoline moiety have the hydroxyl group replaced by the acetyl group as a protective group for the hydroxyl function. Therefore, an additional deprotection step was carried out in order to obtain two novel hydroxylated 1,3,4-oxadiazoline derivatives from 3-OAc, 4-OAc derivatives. All the new 1,6-diphenyl-3-methyl-4-(substituted)-1H-pyrazolo[3,4-b]pyridine derivatives were obtained with yields ranging from 70 to 95% and had their structures elucidated by spectroscopic methods. These compounds were evaluated in vitro against intracellular amastigote form of T. cruzi, using the benznidazole drug as the positive control and had their cytotoxicity profiles determined on LLCMK₂ mammalian cells. All derivatives tested have shown some trypanocidal activity. The N’-2-hydroxybenzylidene-carbohydrazide and 2-(N’-acetyl-1,3,4-oxadiazolin-2-yl)-phenyl acetate derivatives showed the most significant antichagasic activity (IC₅₀= 0.85 and 1.11 μM, respectively) in comparison to benznidazole drug (IC₅₀= 3.98 μM) in addition to low cytotoxicity. These results suggest that the 2-substituted position of phenyl group connected to the carbohydrazide or oxadiazoline moiety play an important role in antichagasic activity of 1,6-diphenyl-4-(substituted)-1H-pyrazolo[3,4-b]pyridines compounds. Furthermore, our results indicate bioisosteric replacement of carbohydrazide moiety by 1,3,4-oxadiazoline ring.

Introduction: In the current scenario of antiviral research, lactic acid bacteria (LAB) and their derived polymers or polysaccharides are considered potential candidates in antiviral therapy to prevent or treat viral infections in both human and animals with remarkable efficacy and might have significant contribution in medicine and pharmaceutical industries in future. The aim of this work was to study the anti-herpetic activity of exopolysaccharides produced by Leuconostoc sp.

Methodology: The strains of the LAB were isolated from fermented homemade vegetables: apples, tomato juice, and sauerkraut. Exopolysaccharides (EPSs) were isolated from the culture fluid. Cytotoxicity and antiherpetic activity of 7 EPSs (15a, 48a, 33a, 43a, 2t, 19s, and 6s) were studied using MTT assay. The influence of EPSs on the herpes simplex virus 1 type (HSV-1) was determined by the virucidal, adsorption and penetration assays. The impact of the EPSs on the cell cycle under a condition of HSV-1 infection was analyzed using flow cytometric analysis of propidium iodide-stained cells.

Results: All EPSs demonstrated the minimal cytotoxicity of cells and their CC₅₀ values were >3.5 mg/ml. It was determined, that only EPSs 2t, 19s, and 6s significantly inhibited HSV-1 reproduction; their EC₅₀ value equal to 0.2 and 0.5 mg/ml, and the selectivity index was in the range of 39 – 52. Moreover, their showed virucidal activity when were added to virus 3 h before adsorption reduced HSV-1 infectivity by 86 – 97%. Our studies revealed that these EPSs were able to prevent the HSV-1 attachment to cells and penetration into cells in a different manner, reducing HSV-1 production by 70 – 99 %. Furthermore, the normalization of the number of cells in all phases of the cell cycle compared with the profile of infected cells and the increasing number of cells in G1 phase to 79% compared with the control values of viral infections were determined after using of EPSs.

Conclusion: This study presents the first data indicating an enormous potential of using EPSs the genus Leuconostoc sp. for lower or hinder the spread of diseases caused by herpesviruses.

Funding: Publications are based on the research provided by the grant support of the State Fund for Fundamental Research (project F83).

Epstein–Barr virus (EBV) causes lymphocyte-proliferative diseases, such as Burkitt’s lymphoma, Hodgkin’s lymphoma, other B and T cell lymphomas. Recently the connection between EBV and autoimmunity diseases has been demonstrated. In recent years, several studies have explored the concept that the compounds that have anti-herpetic activity might be able to influence the cell cycle of infected cells, by eliminating them from the body. However, cell cycle regulation during EBV-infection and the effect of anti-EBV drugs have received only limited attention.

The aim of our work was to study derivatives of triazole (G14, G20, G22, and G24) as potential antiherpetic agent and their effect on the cell cycle of lymphoblastoid cell lines B95-8. According to PCR, anti-EBV activity was observed only for compounds G14 and G22, EC50 values were 27 and 100µg/ml. The В95-8 cells treated with all studied compounds were analyzed with the help of flow cytometry (cells were stained with propidium iodide). It was observed an induction of apoptosis in the presence of G22 at 700µg/ml; the proportion of apoptotic cells reached almost 40%. Other compounds G14 and G24 led to the switch of cells from the Sub G0 phase of the cell cycle to the G1 phase and subsequent activation of the S-phase. These compounds may play an important role as potential inducers of EBV lytic infection; with the addition of antiherpesvirus drugs, they could be therapeutically beneficial for EBV-associated tumors.

The report discusses the latest achievements of the authors in developing original methods for stereoselective synthesis of natural acetogenins, higher bis-methylene-separated (interrupted) di- and trienoic acids, lembehynes that are of exceptional interest as low-toxic target antitumor drugs, as well as compounds with neritogenic activity for treating neurodegenerative diseases.

The synthetic approaches to the above listed natural compounds are based on the use at the key stage of the synthesis, of new organometallic reactions, such as Ti-catalyzed homo- and cross-cyclomagnesiation of 1,2-dienes, discovered in the Laboratory of Catalytic Synthesis of the IPC RAS, involving available Grignard reagents.

The studies of the synthesized compounds for their antitumor and antibacterial activities in vitro were performed with the use of unique equipment in “Centre for Molecular Design and Biological Screening of Candidate Substances for the Pharmaceutical Industry” at the Institute of Petrochemistry and Catalysis of RAS using modern methods such as flow cytofluorometry, fluorescence microscopy and western blotting.

In silico studies into regularities of the structural influence of the synthesized compounds on their antitumor activity were fulfilled with the use of molecular docking and molecular dynamics experiments.

For compounds that showed the greatest activity, in vivo tests were performed for linear mice with grafted malignant Lewis carcinoma.

Fluorquinolones (FQs) and sulfonamides (SAs) are antibacterial compounds widely used in therapeutics. The combination of antibacterials is a strategy commonly employed to overcome resistance and to improve pharmacokinetic properties. So, the aims of this study were to design, prepare and characterize a multicomponent solid formed by the FQ norfloxacin (NOR) and the SA sulfamethoxazole (SMX), and to evaluate the in vitro antibacterial activity of their combinations. SMX and NOR were ground with acetonitrile. The obtained solid was analyzed by melting point (m.p), ¹H NMR, hot stage microscopy, differential scanning calorimetry (DSC), thermogravimetry, powder X-ray diffraction (PXRD) and DRIFT.¹ The antibacterial effect of NOR, SMX and NOR-SMX was evaluated against Escherichia coli ATCC 25922 using the macrodilution method and checkerboard. The minimum inhibitory concentration (MIC) and the fractional inhibitory concentration (CIF) were determined.² The solid obtained showed m.p. and DSC extrapolated onset temperatures different from NOR or SMX, and both components were present in the solid in a 1:1 ratio. The PXRD patterns demonstrated that NOR and SMX form a new solid phase. Results of the checkerboard method showed synergistic effect, with a FIC index of 0.40.³ These results are very promising and we continue developing new biopharmaceutical assays.

References:

1. Pinto Vitorino, G.; Sperandeo, N. R.; Caira, M.; Mazzieri, M. R. Crystal Growth & Design, 13: 1050-58. 2013.
2. Eliopoulos GM, Moellering Jr RC. Antimicrobial combinations. En: Lorian V, editor. Antibiotics in laboratory medicine, 4 ed. Baltimore, Md: The Williams & Wilkins Co. 1996.
3. Pinto Vitorino G, Becerra MC, Barrera GD, Caira MR, Mazzieri MR. Biological and Pharmaceutical Bulletin, 2017, 40, 758–764.