Synthetic hydrazones: In silico studies and in vitro evaluation of the antileishmania potential.

Bioprospecting and synthesis of strategically designed molecules have been used in the search for drugs that can be in leishmaniasis. Hydrazones (HDZ) are promising compounds with extensive biological activities. The objective of this work was to perform in silico studies of hydrazones 1-5 and to evaluate their antileishmanial, cytotoxic and macrophage immunomodulatory potential in vitro. Hydrazones were subjected to prediction and molecular docking studies. Antileishmanial protocols on promastigotes and amastigotes of Leishmania amazonensis, cytotoxicity and macrophage immunomodulatory activity were performed. Hydrazones showed a good pharmacokinetic profile and hydrazone 3 and hydrazone 5 were classified as non-carcinogenic. Hydrazone 5 obtained the best conformation with trypanothione reductase. Hydrazone 1 and hydrazone 3 obtained the best mean inhibitory concentration (IC50) values for promastigotes, 4.4-61.96 µM and 8.0-58.75 µM, respectively. It also showed good activity on intramacrophagic amastigotes, with hydrazone 1 being the most active (IC50 = 6.79 µM) with selectivity index of 56. In cytotoxicity to macrophages hydrazone 3 was the most cytotoxic (CC50 = 256.3 ± 0,04 µM), while hydrazone 4 the least (CC50 = 1055.9 ± 0.03 µM). It can be concluded that the hydrazones revealed important pharmacokinetic and toxicological properties, in addition to antileishmania potential in reducing infection and infectivity in parasitized macrophages.

Biopolymer from Water Kefir as a Potential Clean-Label Ingredient for Health Applications: Evaluation of New Properties.

The present work aimed to characterize the exopolysaccharide obtained from water kefir grains (EPSwk), a symbiotic association of probiotic microorganisms. New findings of the technological, mechanical, and biological properties of the sample were studied. The EPSwk polymer presented an Mw of 6.35 × 105 Da. The biopolymer also showed microcrystalline structure and characteristic thermal stability with maximum thermal degradation at 250 °C. The analysis of the monosaccharides of the EPSwk by gas chromatography demonstrated that the material is composed of glucose units (98 mol%). Additionally, EPSwk exhibited excellent emulsifying properties, film-forming ability, a low photodegradation rate (3.8%), and good mucoadhesive properties (adhesion Fmax of 1.065 N). EPSwk presented cytocompatibility and antibacterial activity against Escherichia coli and Staphylococcus aureus. The results of this study expand the potential application of the exopolysaccharide from water kefir as a potential clean-label raw material for pharmaceutical, biomedical, and cosmetic applications.

Naphthoquinone-based Hydrazone Hybrids: Synthesis and Potent Activity Against Cancer Cell Lines.

BACKGROUND: Natural naphthoquinones have shown diversified biological activities including antibacterial, antifungal, antimalarial, and cytotoxic activities. However, they are also compounds with acute cytotoxicity, immunotoxicity, carcinogenesis, and cardio- and hepatotoxicity, and the modification at their redox center is an interesting strategy to overcome such harmful activity. OBJECTIVE: In this study, four novel semisynthetic hydrazones, derived from the isomers α- and ß- lapachones (α and ß, respectively) and coupled with the drugs hydralazine (HDZ) and isoniazid (ACIL), were prepared, evaluated by electrochemical methods and assayed for anticancer activity. METHODS: The semisynthetic hydrazones were obtained and had their molecular structures established by NMR, IR, and MS. Anticancer activity was evaluated by cell viability determined by reduction of 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide (MTT). The electrochemical studies, mainly cyclic voltammetry, were performed, in aprotic and protic media. RESULTS: The study showed that the compounds 2, 3, and 4 were active against at least one of the cancer cell lines evaluated, compounds 3 and 4 being the most cytotoxic. Toward HL-60 cells, compound 3 was 20x more active than ß-lapachone, and 3x more cytotoxic than doxorubicin. Furthermore, 3 showed an SI value of 39.62 for HL-60 cells. Compound 4 was active against all cancer cells tested, with IC50 values in the range 2.90-12.40 µM. Electrochemical studies revealed a profile typical of self-protonation and reductive cleavage, dependent on the supporting electrolyte. CONCLUSION: These results therefore indicate that compounds 3 and 4 are strong candidates as prototypes of new antineoplastic drugs.

Preclinical anticancer effectiveness of a fraction from Casearia sylvestris and its component Casearin X: in vivo and ex vivo methods and microscopy examinations.

ETHNOPHARMACOLOGICAL RELEVANCE: Casearia sylvestris (Salicaceae) is found in South America and presents antiulcerogenic, cytotoxic, antimicrobial, anti-inflammatory and antihypertensive activities. AIM OF THE STUDY: To assess the in vivo and ex vivo antitumor action of a fraction with casearins (FC) and its main component - Casearin X-isolated from C. sylvestris leaves. MATERIALS AND METHODS: Firstly, Sarcoma 180 bearing Swiss mice were treated with FC and Cas X for 7 days. Secondly, BALB/c nude animals received hollow fibers with colon carcinoma (HCT-116) or glioblastoma (SF-295) cells and were treated with FC for 4 days. On 5th day, proliferation was determined by MTT assay. RESULTS: FC 10 and 25mg/kg/day i.p. and 50mg/kg/day oral and Cas X 25mg/kg/day i.p. and 50mg/kg/day oral revealed tumor growth inhibition rates of 35.8, 86.2, 53.7, 90.0 and 65.5% and such tumors demonstrated rare mitoses and coagulation necrosis areas. Similarly, FC reduced multiplying of HCT-116 and SF-295 cells when evaluated by the Hollow Fiber Assay (2.5 and 5mg/kg/day i.p. and 25 and 50mg/kg/day oral), with cell growth inhibition rates ranging from 33.3 to 67.4% (p<0.05). Flow cytometry experiments revealed that FC reduced membrane integrity and induced DNA fragmentation and mitochondrial depolarization (p<0.05). CONCLUSIONS: FC and Cas X were efficient antitumor substances against murine and human cancer cells and caused reversible morphological changes in liver, kidneys and spleens, emphasizing clerodane diterpenes as an emerging class of anticancer molecules.

Biomedical properties and potentiality of Lippia microphylla Cham. and its essential oils.

Lippia microphylla Cham. (Verbenaceae) is an endemic underexploited Brazilian vegetal. This work reviewed the biological potentialities of Lippia microphylla, emphasizing the properties of essential oils (EOs) and analyzed scientific indicators about genus Lippia and L. microphylla. Databases from 1948 to the present were searched and a software (vantage point 7.1) associated with Derwent Innovation Index was used to identify the indicators of the genus Lippia, and biological activities and compounds in the L. macrophylla species. Ethnopharmacological records report use of L. microphylla leaves to treat gastrointestinal disorders, influenza, bronchitis, cough, nasal congestion, and sinusitis during vaporization, whose aromatic volatile oils are rich in monoterpenes, especially cineole, terpineol, and thymol. Other EOs have larvicidal activity on Aedes aegypti larvae, and antifungal, antibacterial and cytotoxic and antitumor action on human and murine cancer cells. Brazil is the country with more articles about Lippia species, but it deposited only 9 patents since 1993. Most of the publications about L. microphylla are concentrated in food and chemical sciences. This bioprospection helps to choice areas of interest for capital investment and to give support for Brazilian Institutions to establish cooperation and improve technological impact at the point of view of creation and innovation.

Improvement of in vivo anticancer and antiangiogenic potential of thalidomide derivatives.

The strategy of antiangiogenic drugs is based on inhibiting formation of new blood vessels as alternative to limit cancer progression. In this work, we investigated the antitumor and antiangiogenic potential of eight thalidomide derivatives. Most of the molecules was not cytotoxic but 2a, 2d and 3d revealed weak antiproliferative activity on HL-60, Sarcoma 180 (S180) and normal peripheral blood mononuclear cells. Thalidomide, 2a and 2b were able to inhibit tumor growth (53.5%, 67.9% and 67.4%, respectively) in S180-bearing mice and presented moderate and reversible toxicity on liver, kidneys and spleens. Both analogs (2a and 2b) inhibited cell migration of endothelial (HUVEC) and melanoma cells (MDA/MB-435) at 50µg/mL. Immunohistochemistry labeling assays with CD-31 (PECAM-1) antibody showed microvascular density (MVD) was significantly reduced in thalidomide, 2a and 2b groups (30±4.9, 64.6±1.8 and 46.5±19.5%, respectively) (p<0.05). Neovascularization evaluated by Chorioallantoic Membrane Assay (CAM) with compounds 2a and 2b showed reduction of vessels' number (12. 9±2.3 and 14.8±3.3%), neovascularization area (13.1±1.7 and 14.3±1.7%) and total length of vessels (9.2±1.5 and 9.9±1.9%). On the other hand, thalidomide did not alter vascularization parameters. Consequently, addition of thiosemicarbazone pharmacophore group into the phthalimidic ring improved the in vivo antitumor and antiangiogenic potential of the analogs 2a and 2b.

C. pseudotuberculosis Phop confers virulence and may be targeted by natural compounds.

The bacterial two-component system (TCS) regulates genes that are crucial for virulence in several pathogens. One of such TCS, the PhoPR system, consisting of a transmembrane sensory histidine kinase protein (PhoR) and an intracellular response regulator protein (PhoP), has been reported to have a major role in mycobacterial pathogenesis. We knocked out the phoP in C. pseudotuberculosis, the causal organism of caseous lymphadenitis (CLA), and using a combination of in vitro and in vivo mouse system, we showed for the first time, that the PhoP of C. pseudotuberculosis plays an important role in the virulence and pathogenicity of this bacterium. Furthermore, we modeled the PhoP of C. pseudotuberculosis and our docking results showed that several natural compounds including Rhein, an anthraquinone from Rheum undulatum, and some drug-like molecules may target PhoP to inhibit the TCS of C. pseudotuberculosis, and therefore may facilitate a remarkable attenuation of bacterial pathogenicity being the CLA. Experiments are currently underway to validate these in silico docking results.