Daniel R. Callejon

Isolation, functional, and partial biochemical characterization of galatrox, an acidic lectin from Bothrops atrox snake venom

Snake venom lectins have been studied in regard to their chemical structure and biological functions. However, little is known about lectins isolated from Bothrops atrox snake venom. We report here the isolation and partial functional and biochemical characterization of an acidic glycan-binding protein called galatrox from this venom. This lectin was purified by affinity chromatography using a lactosyl-sepharose column, and its homogeneity and molecular mass were evaluated by high-performance liquid chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. The purified galatrox was homogeneous and characterized as an acidic protein (pI 5.2) with a monomeric and dimeric molecular mass of 16.2 and 32.5 kDa, respectively. Alignment of N-terminal and internal amino acid sequences of galatrox indicated that this protein exhibits high homology to other C-type snake venom lectins. Galatrox showed optimal hemagglutinating activity at a concentration of 100 μg/ml and this effect was drastically inhibited by lactose, ethylenediaminetetraacetic acid, and heating, which confirmed galatroxs lectin activity. While galatrox failed to induce the same level of paw edema or mast cell degranulation as B. atrox crude venom, galatrox did alter cellular viability, which suggested that galatrox might contribute to venom toxicity by directly inducing cell death.

Leishmanicidal Evaluation of Tetrahydroprotoberberine and Spirocyclic Erythrina-Alkaloids

Leishmaniasis is one of the World’s most problematic diseases in developing countries. Traditional medicines to treat leishmaniasis have serious side effects, as well as significant parasite resistance problems. In this work, two alkaloids 1 and 2 were obtained from Corydalis govaniana Wall and seven alkaloids 3–9, were obtained from Erythrina verna. The structures of the compounds were confirmed by mass spectrometry and 1D- and 2D-NMR spectroscopy. The leishmanicidal activity of compounds 1–9 against Leishmania amazonensis was tested on promastigote forms and cytotoxicity against J774 (macrophage cell line) was assessed in vitro. Compound 1 showed potent activity (IC50 = 0.18 µg/mL), compared with the standard amphotericin B (IC50 = 0.20 µg/mL). The spirocyclic erythrina-alkaloids showed lower leishmanicidal activity than dibenzoquinolizine type alkaloids.

Fotoprotetores derivados de produtos naturais: perspectivas de mercado e interações entre o setor produtivo e centros de pesquisa

Ultraviolet radiation is the major exogenous mediators of skin damage. To prevent such damage, sunscreen products are used. New research aims at both the elucidation of new sunscreen compounds, as well as new assets for supporting and synergistic action. In this article it is presented a systematic data of innovation for sunscreen and a discussion on prospects for partnership between universities and enterprises, where it is believed that the innovations in cosmetics, driven by the constant demand of the market in new products, may be a stimulus for the interactions between university and company in Brazil.

In vitro metabolism of grandisin, a lignan with anti-chagasic activity.

Tetrahydrofuran lignans represent a well-known group of phenolic compounds capable of acting as antiparasitic agents. In the search for new medicines for the treatment of Chagas disease, one promising compound is grandisin which has shown significant activity on trypomastigote forms of Trypanosoma cruzi. In this work, the in vitro metabolism of grandisin was studied in the pig cecum model and by biomimetic phase I reactions, aiming at an ensuing a preclinical pharmacokinetic investigation. Although grandisin exhibited no metabolization by the pig microbiota, one putative metabolite was formed in a biomimetic model using Jacobsen catalyst. The putative metabolite was tested against T. cruzi revealing loss of activity in comparison to grandisin.

Application of the Negishi reaction in the synthesis of thiophene-based lignans analogues with leishmanicidal effects

As lignanas tetraidrofurânicas sao metabolitos secundarios com reconhecida atividade antiprotozoaria. Na literatura, ha varios relatos sobre os efeitos anti-parasitarios de analogos sinteticos de lignanas contendo pontes de enxofre. Neste trabalho, foi realizada a sintese de analogos tiofenicos de lignanas com o uso de uma estrategia sintetica seletiva e de alto desempenho baseada na reacao de acoplamento cruzado de Negishi. Os derivados sinteticos foram obtidos de maneira rapida e apresentaram alto grau de pureza e baixa toxicidade para uma linhagem celular de mamifero e atividade leishmanicida com diferentes potencias. Lignans represent a well-known group of natural products with anti-protozoal activity. In the literature there are many examples of the anti-parasitic activity of synthetic analogues of lignans containing sulphur bridges. In this work, we have obtained thiophene-based analogues by using a selective and high performance synthetic strategy based on the Negishi cross-coupling reaction. The derivatives were quickly obtained and showed great purity, low toxicity toward a mammalian cell line, and leishmanicidal activity with different potencies.

New cascarosides from Rhamnus purshiana and fragmentation studies of the class by IT-MS

RATIONALE Anthrone and oxanthrone are important anthraquinone derivatives present in medicinal plants which are used in therapeutics as laxatives. Some of these plants need to be stored at least one year before they can be used in order to oxidize anthrones into oxanthrones, so to avoid severe diarrhea and dehydration. Therefore, this work aimed to characterize fragmentation reactions between these anthraquinones to provide an easy way to differentiate between the two classes, since it is necessary and important to discriminate and identify these derivatives in laxative plants and phytotherapic drugs. METHODS Anthrone (cascarosides A-D) and oxanthrone (10-hydroxycascaroside A and B) derivatives were isolated and identified by NMR (1 H, 13 C, DEPT, NOESY) and used for fragmentation study by direct infusion on an electrospray ionization (ESI) ion trap mass spectrometer (AmazonSL, Bruker) in positive and negative mode. RESULTS The additional hydroxyl at C-10 in oxanthrones allowed McLafferty-type rearrangements to form the quinone group in positive mode, while in negative mode the second sugar loss infringed the odd-electron rule and formed a radical fragment. No differences in fragmentation reactions were found between diastereoisomeric pairs, although the additional oxygen at C-10 of oxanthrones allowed a different fragmentation pattern. CONCLUSIONS The proposed fragmentation patterns can be used to differentiate anthrones from oxanthrones in both ion modes. In addition, they can be applied to differentiate these compounds in anthraquinone-rich plants and phytotherapic drugs. Finally, herein, the strategy applied allowed us to identify new natural products. Copyright

Pharmacokinetic properties, in vitro metabolism and plasma protein binding of govaniadine an alkaloid isolated from Corydalis govaniana Wall

Govaniadine (GOV) is an alkaloid isolated from Corydalis govaniana Wall. It has been reported to show a different number of biological activities including anti-urease, leishmanicidal and antinociceptive. The present study aims to characterize the GOV in vitro metabolism after incubation with rat and human liver microsomes (RLM and HLM, respectively) and to evaluate its pharmacokinetic properties. The identification of GOV metabolites was conducted by different mass analyzers: a micrOTOF II-ESI-ToF Bruker Daltonics® and an amaZon-SL ion trap (IT) Bruker Daltonics®. For the pharmacokinetic study of GOV in rats after intravenous administration, a LC-MS/MS method was developed and applied to. The analyses were performed using an Acquity UPLC® coupled to an Acquity TQD detector equipped with an ESI interface. The liver microsomal incubation resulted in new O-demethylated, di-hydroxylated and mono-hydroxylated compounds. Regarding the method validation, the calibration curve was linear over the concentration range of 2.5-3150.0ngmL-1, with a lower limit of quantitation (LLOQ) of 2.5ngmL-1. This method was successfully applied to a pharmacokinetic study. The profile was best fitted to a two-compartment model, the first phase with a high distribution rate constant (α) 0.139±0.086min-1, reflected by the short distribution half-life (t1/2α) 9.2±8.9min and the later one, with an elimination half-life (t1/2β) 55.1±37.9min. The main plasma protein binding was 96.1%. This is a first report in this field and it will be useful for further development of govaniadine as a drug candidate.

Transdermal estradiol and lipid profile: effects on a specific group of Brazilian postmenopausal women

BACKGROUND In postmenopausal women, significant changes occur that can induce cardiovascular diseases, such as atherogenic lipid profile, due to an increase in total cholesterol and LDL levels, and a decrease in HDL cholesterol levels. The hormone replacement therapy (HRT) can prevent these changes in lipid profile. OBJECTIVE Verify the effects of HRT consisting of transdermal estradiol gel associated with medroxyprogesterone acetate on the lipid profile and biochemical parameters in Brazilian postmenopausal women. METHODS This study is an open prospective longitudinal study, in which thirty postmenopausal women received transdermal estradiol gel (1 mg/day) continuously combined with oral medroxyprogesterone acetate (MPA) (5 mg/day) for 12 days/month. The following parameters were determined: total cholesterol, triglycerides, high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gama glutamyl transferase (GGT) and follicle-stimulating hormone (FSH). RESULTS The parameters of the lipid profile did not show a significant decrease, while the levels of GGT and FSH had a statistically significant decrease. CONCLUSIONS the treatment with transdermal estradiol gel did not have a significant impact on the lipid profile, thus not resulting in a beneficial effect on cardiovascular disease markers, suggesting that the dose, administration route and the time of treatment were important for these results. Moreover, the treatment using small dose and the transdermal administration route also had a significant hepatic effect in this population. Therefore, this treatment might provide interesting effects on the lipid profile in Brazilian postmenopausal women.FUNDAMENTO: Cambios significantes ocurren en las mujeres posmenopausicas que pueden inducir enfermedades cardiovasculares, tales como el perfil lipidico aterogenico debido a un aumento en los niveles de colesterol total y LDL y una disminucion en los niveles de HDL. La terapia de reemplazo hormonal (TRH) puede evitar esos cambios en el perfil lipidico. OBJETIVO: Determinar los efectos de la TRH constituida por estradiol transdermico y acetato de medroxiprogesterona en los parametros bioquimicos y lipidicos de mujeres brasilenas posmenopausicas METODOS: Este es un estudio prospectivo, longitudinal, abierto, en el que treinta mujeres posmenopausicas recibieron estradiol en gel transdermico (1 mg/dia) de forma continua, combinado con acetato de medroxiprogesterona (MPA) (5 mg/dia) por 12 dias/mes. Se determinaron los seguientes parametros: colesterol total, trigliceridos, lipoproteina de alta densidad (HDL-colesterol), lipoproteina de baja densidad (LDL-colesterol), lipoproteina de muy baja densidad (VLDL-colesterol), glucosa, aspartato transaminasa (AST), alanina aminotransferasa (ALT), Gammaglutamiltranspeptidasa (GGT) y hormona foliculoestimulante (FSH). RESULTADOS: Los parametros del perfil lipidico mostraron una disminucion insignificante, mientras los niveles de GGT y FSH presentaron una disminucion estadisticamente significante. CONCLUSIONES: El tratamiento con estradiol en gel transdermico no mostro un impacto significante en el perfil lipidico, causando un efecto benefico en los marcadores de enfermedades cardiovasculares, sugiriendo que la dosis, el modo de administracion y el tiempo de tratamiento fueron importantes para esos resultados. Ademas, el tratamiento con dosis baja y modo de administracion transdermico tambien demostro un significante efecto hepatico en esa poblacion. Asi pues, ese tratamiento puede surtir efectos interesantes sobre el perfil lipidico en las mujeres brasilenas posmenopausicas.

Chemical Composition and Acaricidal Activity against Tetranychus urticae of Essential Oil from Marsypianthes chamaedrys (Vahl.) Kuntze

Marsypianthes chamaedrys (Vahl.) Kuntze, known as paracari, erva de cobra, boia-caa or betonia brava, is a common herb in Brazil (North and Northeast regions). The aerial parts (leaves and stem) of this plant were used to essential oil extraction. The essential oil obtained was evaluated against Tetranychus urticae showing no significant acaricidal activity. Analysis by GC-MS was performed and 29 compounds were identified and the main compounds were the sesquiterpenes β-caryophyllene (12.2%), bicyclogermacrene (17.9%) and germacrene D (34.1%).

Copaiba Oil and Its Constituent Copalic Acid as Chemotherapeutic Agents against Dermatophytes

Copaiba oil, an oleoresin extracted from Copaifera genus, has been widely used in popular medicine for the treatment of several diseases. The aim of this study was to investigate the antifungal activity of the copaiba oil and its isolated compounds caryophyllene oxide, copalic acid and acetoxycopalic acid against Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum gypseum strains, using microdilution method and microscopy techniques. It was found that the copaiba oil and the copalic acid were active against dermatophytes by minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) tests. The MIC and MFC of copaiba oil against T. rubrum, T. mentagrophytes and M. gypseum were 125 μg mL (250 μg mL), 500 μg mL (500 μg mL) and 250 μg mL (250 μg mL), respectively. For copalic acid, the MIC and MFC were 50 μg mL (100 μg mL), 100 μg mL (100 μg mL) and 50 μg mL (100 μg mL), respectively. Fluorescence microscopy and scanning electronic microscopy were used to investigate inhibition on hyphal growth by compounds, copaiba oil and copalic acid, showing a strong inhibition and an irregular growth pattern. Cell wall, cytoplasmic membrane and intracellular contents were also damaged. In conclusion, copaiba oil and copalic acid showed great activity against dermatophytes, being potential compounds for the development of antifungal drugs.