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1.
Food Funct ; 15(3): 1527-1538, 2024 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-38231081

RESUMEN

Foods rich in riboflavin (Rf) are susceptible to degradation due to oxidative processes with the formation of radicals. Herein, we describe the features and stability of an Mg(II) complex containing ferulic acid (fer) and 1,10-phenanthroline (phen) as chelators: henceforth called Mg(phen)(fer). The electrochemical behavior of Mg(phen)(fer) is pH dependent and results from the stabilisation of the corresponding phenoxyl radical via complexation with Mg(II). This stabilisation enhances the antioxidant activity of Mg(phen)(fer) with respect to free fer and commercial antioxidants. Mg(phen)(fer) scavenges and neutralizes DPPH˙ (IC50 = 15.6 µmol L-1), ABTS˙+ (IC50 = 5.65 µmol L-1), peroxyl radical (IC50 = 5.64 µg L-1) and 1O2 (IC50 = 0.7 µg m-1). Mg(phen)(fer) effectively protects riboflavin (Rf) against photodegradation by quenching the singlet excited states of Rf regardless of the conditions. Also, the complex Mg(phen)(fer) was effectively incorporated into starch films, broadening its applications, as shown by microbiological studies. Thus, Mg(phen)(fer) has high potential for use in Rf-rich foods and to become a new alternative to the synthetic antioxidants currently used.


Asunto(s)
Antioxidantes , Quelantes , Antioxidantes/farmacología , Antioxidantes/química , Riboflavina/química , Ácidos Cumáricos
2.
Z Naturforsch C J Biosci ; 76(3-4): 111-115, 2021 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-33099518

RESUMEN

The fall armyworm, Spodoptera frugiperda, is a polyphagous pest that causes important damage in different regions of America and mainly affects corn crops in both tropical and subtropical areas. Currently, control relies on both transgenic plants and/or chemical pesticides. In this work, we describe insecticidal activity against the fall armyworm from a series of Mannich bases (1-10), derived from 2-hydroxy-1,4-naphthoquinone (lawsone), substituted benzaldehydes, and two primary amines, and their Cu2+ complexes (11-20). The [Cu(L)2] complexes were more effective in larval mortality compared to the free Mannich bases. Among the tested compounds, complex 11 showed the highest toxicity, with 70.00% larval mortality.


Asunto(s)
Insecticidas/farmacología , Naftoquinonas/farmacología , Spodoptera/efectos de los fármacos , Zea mays/microbiología , Animales , Proteínas Bacterianas/genética , Cobre/química , Cobre/farmacología , Humanos , Larva/microbiología , Bases de Mannich , Control de Plagas , Plantas Modificadas Genéticamente/microbiología , Spodoptera/patogenicidad
3.
Bioorg Med Chem ; 28(15): 115597, 2020 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-32631567

RESUMEN

Cathepsin K (CatK) is a cysteine protease known for its potent collagenolytic activity, being recognized as an important target to the development of therapies for the treatment of bone disorders. Epoxypeptidomimetics have been reported as potent inhibitors of cathepsins, thus in this work we present a green synthesis of new peptidomimetics by using a one-pot asymmetric epoxidation/Ugi multicomponent reaction. The compounds were evaluated against CatK showing selectivity when compared with cathepsin L, with an inhibition profile in the low micromolar IC50 range. Investigation of the mechanism of action carried out for compounds LSPN428 and LSPN694 suggested a mixed inhibition mode and docking studies allowed a better understanding about interactions of inhibitors with the enzyme.


Asunto(s)
Catepsina K/antagonistas & inhibidores , Inhibidores de Cisteína Proteinasa/química , Compuestos Epoxi/química , Peptidomiméticos/química , Dominio Catalítico , Catepsina K/química , Catepsina K/metabolismo , Inhibidores de Cisteína Proteinasa/síntesis química , Inhibidores de Cisteína Proteinasa/metabolismo , Compuestos Epoxi/síntesis química , Compuestos Epoxi/metabolismo , Tecnología Química Verde , Humanos , Simulación del Acoplamiento Molecular , Estructura Molecular , Peptidomiméticos/síntesis química , Peptidomiméticos/metabolismo , Unión Proteica , Relación Estructura-Actividad
4.
J Nat Prod ; 83(6): 1859-1875, 2020 06 26.
Artículo en Inglés | MEDLINE | ID: mdl-32530627

RESUMEN

In this study, HPLC-PDA-HRMS-SPE-NMR data were used for initial analysis of the CH2Cl2 fraction of an EtOH extract of the leaves of Picramnia glazioviana. The HRMS, UV, and NMR data obtained from the HPLC-PDA-HRMS-SPE-NMR analysis were used to direct semipreparative HPLC isolation toward nortriterpenoids, which resulted in the isolation of 18 new and highly oxygenated nortriterpenoids (1-3, 5-10, 12-19, and 21), named picravianes C-T. Their structures were determined on the basis of analysis of UV, HRMS, and 2D NMR spectroscopic data, including determination of the relative configuration on the basis of coupling pattern analysis and nuclear Overhauser effect correlations. The absolute configurations of compounds 7, 9, 10, 14, 15, 17, 18, 19, and 21 were assigned using electronic circular dichroism data, and the cytotoxicity of compounds 6, 10, 14, 16, 17, 18, 19, and 21 was evaluated against MDA-MB-231 triple-negative breast cancer, SKBR-3 Her2-overexpressing breast cancer, and A549 lung cancer cells lines. The isolated compounds contain a hitherto undescribed modification of the terminal backbone and/or E-ring, and a possible biosynthetic pathway for their formation is proposed.


Asunto(s)
Sapindaceae/química , Células A549 , Antineoplásicos Fitogénicos/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Línea Celular Tumoral , Cromatografía Líquida de Alta Presión , Dicroismo Circular , Femenino , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Espectroscopía de Resonancia Magnética , Estructura Molecular , Extractos Vegetales/química , Extractos Vegetales/farmacología , Hojas de la Planta/química , Solventes , Espectrometría de Masa por Ionización de Electrospray , Espectrofotometría Ultravioleta , Triterpenos/química , Triterpenos/aislamiento & purificación
5.
J Nat Prod ; 83(5): 1409-1415, 2020 05 22.
Artículo en Inglés | MEDLINE | ID: mdl-32372647

RESUMEN

Citrus sinensis and Citrus limonia were obtained by germination from seeds, and isotopic-labeling experiments using d-[1-13C]glucose were performed with the seedlings. After 60 days, the seedlings were analyzed by high-performance liquid chromatography-ultraviolet-solid-phase extraction-nuclear magnetic resonance, data and the 13C enrichment patterns of xanthyletin and seselin indicated that the pyran ring was formed by the methylerythritol phosphate pathway and that the coumarin moiety was derived from the shikimate pathway in both compounds. This information regarding the biosynthetic pathway can be used to increase resistance against phytopathogens, because xanthyletin and seselin are reported to have antimicrobial activity on the growth of Xylella fastidiosa, which causes citrus variegated chlorosis in orange.


Asunto(s)
Marcaje Isotópico/métodos , Piranocumarinas/metabolismo , Isótopos de Carbono , Cromatografía Líquida de Alta Presión , Citrus/metabolismo , Citrus sinensis/metabolismo , Espectroscopía de Resonancia Magnética , Estructura Molecular , Enfermedades de las Plantas/microbiología , Piranocumarinas/química , Piranocumarinas/aislamiento & purificación , Ácido Shikímico/metabolismo , Extracción en Fase Sólida , Espectrofotometría Ultravioleta , Xylella/efectos de los fármacos
6.
Antioxidants (Basel) ; 8(10)2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31581463

RESUMEN

The alkaloid ricinine (3-cyano-4-methoxy-N-methyl-2-pyridone) is found in different parts of the Ricinus communis plant and is known to possess several bioactive properties, including strong antioxidant activity. In this study, a new microwave-assisted extraction (MAE) method was developed for the recovery of ricinine from R. communis leaves. The extraction variables studied were extraction temperature (between 125 °C and 175 °C), microwave power (between 500 W and 1000 W), extraction time (between 5 min and 15 min), extraction solvent (between 10% and 90% of EtOAc in MeOH), and solvent-to-sample ratio (between 25:1 mL and 50:1 mL of solvent per gram of the sample). On studying the effects of extraction variables, both solvent and liquid-to-solid ratio were found to exhibit the highest effects on ricinine recovery. A fast (15 min) microwave-assisted extraction method was developed (high temperatures can be applied because the stability of ricinine is proven in the literature), allowing for the recovery of ricinine from R. communis leaves. The study revealed that R. communis leaves had almost 1.5 mg g-1 (dried weight) of ricinine.

7.
Rev. bras. farmacogn ; 29(4): 491-494, July-Aug. 2019. tab, graf
Artículo en Inglés | LILACS | ID: biblio-1042278

RESUMEN

Abstract Bioassay-guided fractionation of Bowdichia virgilioides Kunth, Fabaceae, extracts has led to the isolation of cathepsin V inhibitors. The investigation of the hexane and ethyl acetate extracts allowed the characterization of eleven compounds: lupeol, lupenone, β-sitosterol and stigmasterol in mixture, trans p-coumaric acid ester derivative, syringaresinol, bowdenol, 8-methoxycoumestrol, 3,4-hydroxy-7-methoxyisoflavone, 7,3′-dihydroxy-4′-methoxyisoflavone, and 5,4′-dihydroxy-7′-methoxyisoflavone. Structures of compounds were stablished by 1D and 2D NMR, and MS experiments. Among the isolated compounds, trans p-coumaric acid ester derivative and 8-methoxycoumestrol showed significant inhibition on cathepsin V, which is up to now unexplored.

8.
Nat Prod Res ; 33(16): 2389-2393, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29488401

RESUMEN

Galactia glaucescens leaves are popularly used against snakebites in Brazil. The hydroethanolic extract from aerial parts of G. glaucescens (HEGg) was assayed against the neurotoxicity and myotoxicity induced by Bothrops jararacussu venom. A traditional myographic technique was applied for neurotoxicity and the resulting muscles were treated routinely by light microscopy analysis for myotoxicity. Additionally, the antimicrobial potential of HEGg was evaluated against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa strains, as well as Rutin was isolated for the first time in this specie using chromatographic and spectroscopic methods and its antiophidian property was assessed. HEGg totally prevents the neurotoxicity and myotoxicity effects caused by B. jararacussu, but did not show any antimicrobial effect. Concluding, HEGg and Rutin were able to counteract the toxic effects of the venom and confirmed the antiophidian potential, but not antimicrobial, of G. glaucescens as an alternative for neutralization of B. jararacussu venom.


Asunto(s)
Venenos de Crotálidos/antagonistas & inhibidores , Fabaceae/química , Animales , Bothrops , Brasil , Músculos/efectos de los fármacos , Hojas de la Planta/química
9.
Org Biomol Chem ; 16(24): 4509-4516, 2018 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-29873386

RESUMEN

One of the most widely used methods to assess the stereochemistry of chiral 2(5H)-furanones is an empirical electronic circular dichroism (ECD) helicity rule. In the present work, an extensive experimental and theoretical investigation of the scope of the above-mentioned empirical rule for acetogenins with a hydroxyl group substituted at C-4 revealed a possible exception to this rule. The underlying causes for this observation are discussed with respect to side chain substitutions, conformational requirements, chromophore handedness as well as a qualitative orbital analysis. Further investigation using vibrational circular dichroism (VCD) spectroscopy led to the identification of spectral markers that seem to be more localized and less affected by side chain substitutions. As the presence of a [capital Upsilon]-lactone ring and a hydroxyl group at C-4 is a very common structural feature of Annonaceous acetogenins, we recommend the combined use of ECD and VCD spectroscopy, along with quantum chemical computations, for the stereochemical analysis of structurally related molecules.

10.
Planta Med ; 83(3-04): 312-317, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27599262

RESUMEN

Indiscriminate use of synthetic pesticides can be hazardous to both humans and the environment, but the use of natural products as a source of bio-based products, such as Melia azedarach extracts, is an interesting approach to overcome these hazards. Unfortunately, the limonoids found in M. azedarach with desired insecticidal properties (e.g. azadirachtin) may also be present with limonoids toxic to mammals. The goal of this report was to develop a fast and reliable MS-based experiment to characterize meliatoxins in crude extracts of M. azedarach, in order to provide unequivocal assessment of the safety for extracts for application in the field. MS and MS/MS experiments using MALDI ionization were evaluated as tools for the assignment of characteristic ions produced by each meliatoxin in crude extracts.The use of different experiments in combination, such as the analysis of fragment m/z 557 and [M + Na]+ (adducts ions m/z 681 and m/z 667), MALDI-MS can be used for detection of meliatoxins A1/B1 or A2/B2 in a crude extract and may be used to discriminate meliatoxins A from B, respectively. Subsequent MS/MS experiments can distinguish between the presence of group 1 and/or 2 in each class of meliatoxins classifying the proposed approach as a quick and efficient quality control method of meliatoxins in real M. azedarach samples.


Asunto(s)
Limoninas/química , Melia azedarach/química , Extractos Vegetales/química , Frutas/química , Limoninas/análisis , Limoninas/toxicidad , Extractos Vegetales/aislamiento & purificación , Extractos Vegetales/toxicidad , Control de Calidad , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Espectrometría de Masas en Tándem/métodos
11.
Fish Shellfish Immunol ; 58: 284-291, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27539707

RESUMEN

Camu camu, Myrciaria dubia, is an Amazon plant that presents high levels of vitamin C in its composition. Several studies in animals and humans have demonstrated their efficiency in the prevention and treatment of various diseases. However, there are no reports of its properties in fish. The aim of this study was to evaluate the effect of the oral administration of the extract of this plant in the immune parameters in Nile tilapia, Oreochromis niloticus. 400 Nile tilapia (80 ± 5 g) were randomly distributed into 20 tanks with 1500 L capacity each (20 fish/tank). After a week of adaptation to environmental conditions, it was provided a diet for 5 weeks, using different levels of inclusion of camu camu extract: 0, 50, 100, 250, and 500 mg/kg of feed. Each treatment consisted of four replicates. It was obtained 40.5 mg of vitamin C/g of camu camu pulp powder by high-performance liquid chromatography. At the end of the trial period, fish were inoculated with Aeromonas hydrophila in the swim bladder. Samples were taken after 6; 24 and 48 h of the challenge. Results revealed that fish supplemented with this herb showed significant increase (P < 0.05) in white blood cells counts in blood and exudate, burst respiratory activity, lysozyme activity, serum bactericidal activity, direct agglutination, and melanomacrophage centers count. Red blood cells count, hemoglobin, hematocrit, and biochemical profile of fish supplemented with the herb presented no statistical differences compared to control group (P > 0.05). No histopathological lesions were observed in intestine, kidney, spleen, and gills. It can be concluded that the addition of Myrciaria dubia in tilapia feed improves the immune response and the growth after 5 weeks, especially, at a dose of 500 mg/kg.


Asunto(s)
Cíclidos/inmunología , Suplementos Dietéticos , Enfermedades de los Peces/dietoterapia , Infecciones por Bacterias Gramnegativas/veterinaria , Inmunidad Innata , Myrtaceae/química , Extractos Vegetales/metabolismo , Aeromonas hydrophila/fisiología , Alimentación Animal/análisis , Animales , Dieta/veterinaria , Relación Dosis-Respuesta a Droga , Enfermedades de los Peces/inmunología , Enfermedades de los Peces/microbiología , Infecciones por Bacterias Gramnegativas/dietoterapia , Infecciones por Bacterias Gramnegativas/inmunología , Infecciones por Bacterias Gramnegativas/microbiología , Distribución Aleatoria
12.
Fish Shellfish Immunol ; 47(1): 630-8, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26434713

RESUMEN

Cat's claw (Uncaria tomentosa) is an Amazon herb using in native cultures in Peru. In mammals, it has been described several effects of this herb. However, this is the first report of its use on the diet of fish. The aim of this study was to determinate the effect of this plant on the growth and immune activity in Oreochromis niloticus. Nile tilapia (81.3 ± 4.5 g) were distributed into 5 groups and supplemented with 0 (non-supplement fish), 75, 150, 300, and 450 mg of U. tomentosa.kg(-1) of diet for a period of 28 days. Fish were inoculated in the swim bladder with inactivated Streptococcus agalactiae and samples were taken at 6, 24, and 48 h post inoculation (HPI). Dose dependent increases were noted in some of the evaluated times of thrombocytes and white blood cells counts (WBC) in blood and exudate, burst respiratory activity, lysozyme activity, melanomacrophage centers count (MMCs), villi length, IgM by immunohistochemistry in splenic tissue, and unexpectedly on growth parameters. However, dietary supplementation of this herb did not affect red blood cells count (RBC), hemoglobin, and there were no observed histological lesions in gills, intestine, spleen, and liver. The current results demonstrate for the first time that U. tomentosa can stimulate fish immunity and improve growth performance in Nile tilapia.


Asunto(s)
Uña de Gato/química , Cíclidos/crecimiento & desarrollo , Cíclidos/inmunología , Inmunidad Innata/efectos de los fármacos , Extractos Vegetales/farmacología , Streptococcus agalactiae/fisiología , Alimentación Animal/análisis , Animales , Cíclidos/microbiología , Dieta/veterinaria , Suplementos Dietéticos/análisis , Extractos Vegetales/administración & dosificación , Distribución Aleatoria
13.
Exp Parasitol ; 156: 42-8, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26044356

RESUMEN

Cysteine proteinases (cathepsins) from Leishmania spp. are promising molecular targets against leishmaniasis. Leishmania mexicana cathepsin L is essential in the parasite life cycle and a pivotal in virulence factor in mammals. Natural products that have been shown to display antileishmanial activity were screened as part of our ongoing efforts to design inhibitors against the L. mexicana cathepsin L-like rCPB2.8. Among them, agathisflavone (1), tetrahydrorobustaflavone (2), 3-oxo-urs-12-en-28-oic acid (3), and quercetin (4) showed significant inhibitory activity on rCPB2.8 with IC50 values ranging from 0.43 to 18.03 µM. The mechanisms of inhibition for compounds 1-3, which showed Ki values in the low micromolar range (Ki = 0.14-1.26 µM), were determined. The biflavone 1 and the triterpene 3 are partially noncompetitive inhibitors, whereas biflavanone 2 is an uncompetitive inhibitor. The mechanism of action established for these leishmanicidal natural products provides a new outlook in the search for drugs against Leishmania.


Asunto(s)
Productos Biológicos/farmacología , Catepsina L/antagonistas & inhibidores , Leishmania mexicana/enzimología , Biflavonoides/farmacología , Catepsina B/antagonistas & inhibidores , Catepsina B/genética , Catepsina L/genética , Humanos , Concentración 50 Inhibidora , Cinética , Leishmania mexicana/genética , Quercetina/farmacología , Proteínas Recombinantes/efectos de los fármacos , Proteínas Recombinantes/genética
14.
Exp Brain Res ; 233(9): 2587-96, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26025613

RESUMEN

We analyzed the effects of an anesthetic sciatic nerve block on the cutaneomuscular reflex (cMR) and the cutaneous silent period (cSP) of foot muscles, in order to investigate further the type of fibers involved in their generation. In 14 neurologically normal patients with indication for surgical treatment of hallux valgus, we recorded from the extensor digitorum brevis muscle the reflex responses elicited by high-intensity electrical stimulation of the big toe at various time periods, ranging from 0 to 20 min, after ultrasound-guided sciatic nerve popliteal anesthetic block. The first effect was a delay in cSP onset latency, with no changes in end latency. The cMR remained unaltered up to when subjects were no longer able to maintain the contraction. The effects of local anesthetics on peripheral nerves allow for recognition of the different types of fibers contributing to the cMR and the cSP in muscles of the lower limb.


Asunto(s)
Pie , Mepivacaína/farmacología , Músculo Esquelético/efectos de los fármacos , Reflejo/efectos de los fármacos , Piel/inervación , Anciano , Anciano de 80 o más Años , Anestésicos Locales/farmacología , Estimulación Eléctrica , Electromiografía , Femenino , Lateralidad Funcional/efectos de los fármacos , Hallux Valgus/patología , Hallux Valgus/cirugía , Humanos , Masculino , Persona de Mediana Edad , Músculo Esquelético/fisiología , Tiempo de Reacción/efectos de los fármacos , Tiempo de Reacción/fisiología , Reflejo/fisiología , Nervio Ciático/efectos de los fármacos , Nervio Ciático/fisiología , Nervio Tibial/efectos de los fármacos , Nervio Tibial/fisiología
15.
Nat Prod Commun ; 10(1): 17-20, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25920211

RESUMEN

Limonoids and triterpenes are the largest groups of secondary metabolites and have notable biological activities. Meliaceae and Rutaceae are known for their high diversity of metabolites, including limonoids, and are distinguished from other families due to the frequent occurrence of such compounds. The increased interest in crop protection associated with the diverse bioactivity of these compounds has made these families attractive in the search for new allelopathic compounds. In the study reported here we evaluated the bioactivity profiles of four triterpenes (1-4) and six limonoids (5-10) from Meliaceae and Rutaceae. The compounds were assessed in a wheat coleoptile bioassay and those that had the highest activities were tested on the standard target species Lepidinum sativum (cress), Lactuca sativa (lettuce), Lycopersicon esculentum (tomato) and Allium cepa (onion). Limonoids showed phytotoxic activity and 5α,6ß,8α, 12α- tetrahydro-28-norisotoonafolin (10) and gedunin (5) were the most active, with bioactivity levels similar to, and in some cases better than, those of the commercial herbicide Logran. The results indicate that these products could also be allelochemicals involved in the ecological interactions of these plant species.


Asunto(s)
Alelopatía , Herbicidas/aislamiento & purificación , Limoninas/toxicidad , Meliaceae/química , Rutaceae/química , Triterpenos/toxicidad , Productos Agrícolas/efectos de los fármacos , Limoninas/aislamiento & purificación , Pruebas de Toxicidad
16.
Anal Chim Acta ; 862: 86-93, 2015 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-25682432

RESUMEN

The hemoglobin (Hb) released from erythrocytes is a primary nutritive component for many blood-feeding parasites. The aspartic protease cathepsin D is a hemoglobinase that is involved in the Hb degradation process and is considered an interesting target for chemotherapy intervention. However, traditional enzymatic assays for studying Hb degradation utilize spectrophotometric techniques, which do not allow real-time monitoring and can present serious interference problems. Herein, we describe a biosensor using simple approach for the real-time monitoring of Hb hydrolysis as well as an efficient screening method for natural products as enzymatic inhibitors using a quartz crystal microbalance (QCM) technique. Hemoglobin was anchored on the quartz crystal surface using mixed self-assembled monolayers. The addition of the enzyme caused a mass change (frequency shift) due to Hb hydrolysis, which was monitored in real time. From the frequency change patterns of the Hb-functionalized QCM, we evaluated the enzymatic reaction by determining the kinetic parameters of product formation (k(cat)). The QCM enzymatic assay using immobilized human Hb was shown to be an excellent approach for screening possible inhibitors in complex mixtures, opening up a new avenue for the discovery of novel inhibitors.


Asunto(s)
Productos Biológicos/análisis , Técnicas Biosensibles/instrumentación , Técnicas Biosensibles/métodos , Hemoglobinas/metabolismo , Inhibidores de Proteasas/análisis , Tecnicas de Microbalanza del Cristal de Cuarzo , Productos Biológicos/farmacología , Catepsina D/antagonistas & inhibidores , Catepsina D/metabolismo , Hemoglobinas/análisis , Humanos , Hidrólisis/efectos de los fármacos , Inhibidores de Proteasas/farmacología , Relación Estructura-Actividad , Factores de Tiempo
17.
Nat Prod Res ; 29(23): 2212-4, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25622620

RESUMEN

Cathepsin B (catB) is a cysteine protease involved in tumour progression and represents a potential therapeutic target in cancer. Among the 15 evaluated extracts from cerrado biome, Myrcia lingua Berg. (Myrtaceae) extract demonstrated to be a source of compounds with potential to inhibit catB. Using bioactivity-guided fractionation, we have found flavonols as inhibitors and also some other derivatives were obtained. From the evaluated compounds, myricetin (5) and quercetin (6) showed the most promising results with IC50 of 4.9 and 8.2 µM, respectively, and mode of inhibition as uncompetitive on catB. The results demonstrated polyhydroxylated flavonols as promising inhibitors of catB.


Asunto(s)
Catepsina B/antagonistas & inhibidores , Flavonoles/química , Myrica/química , Extractos Vegetales/química , Flavonoides/química , Humanos , Concentración 50 Inhibidora , Quercetina/química
18.
Chem Biodivers ; 11(9): 1354-63, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25238076

RESUMEN

Cathepsins L (catL) and B play an important role in tumor progression and have been considered promising therapeutic targets in the development of novel anticancer agents. Using a bioactivity-guided fractionation, a series of triterpenoids was identified as a new class of competitive inhibitors towards cathepsin L with affinity values in micromolar range. Among the 14 compounds evaluated, the most promising were 3-epiursolic acid (3), 3-(hydroxyimino)oleanolic acid (9), and 3-(hydroxyimino)masticadienoic acid (13) with IC50 values of 6.5, 2.4, and 2.6 µM on catL, respectively. Most of the evaluated triterpenoids do not inhibit cathepsin B. Thus, the evaluated compounds exhibit a great potential to help in the design of new inhibitors with enhanced potency and affinity towards catL. Docking studies were performed in order to gain insight on the binding mode and SAR of these compounds.


Asunto(s)
Catepsina L/antagonistas & inhibidores , Inhibidores de Cisteína Proteinasa/farmacología , Triterpenos/farmacología , Inhibidores de Cisteína Proteinasa/química , Evaluación Preclínica de Medicamentos , Humanos , Simulación del Acoplamiento Molecular , Myrtaceae/química , Triterpenos/química
19.
Molecules ; 19(8): 12031-47, 2014 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-25120055

RESUMEN

Previous investigations of H. oreadica reported the presence of a wide spectrum of complex limonoids and dihydrocinnamic acids. Our interest in the Rutaceae motivated a reinvestigation of H. oreadica, H. brasiliana and H. superba searching for other secondary metabolites present in substantial amounts for taxonomic analysis. In a continuation of the investigation of the H. oreadica, three new limonoids have now been isolated 9α-hydroxyhortiolide A, 11ß-hydroxyhortiolide C and 1(S*)-acetoxy-7(R*)-hydroxy-7-deoxoinchangin. All the isolated compounds from the Hortia species reinforce its position in the Rutaceae. With regard to limonoids the genus produces highly specialized compounds, whose structural variations do not occur in any other member of the Rutaceae, thus, it is evident from limonoid data that Hortia takes an isolated position within the family. In addition, H. superba afforded the unexpected coumarin 5-chloro-8-methoxy-psoralen, which may not be a genuine natural product. Solid-state cross-polarisation/magic-angle-spinning 13C nuclear magnetic resonance, X-Ray fluorescence and Field-emission gun scanning electron microscopy experiments show that the Sephadex LH-20 was modified after treatment with NaOCl, suggesting that when xanthotoxin (8-methoxy-psoralen) was extracted from cleaning of the gel column, chlorination of the aromatic system occurred.


Asunto(s)
Cumarinas/aislamiento & purificación , Limoninas/aislamiento & purificación , Extractos Vegetales/química , Rutaceae/química , Cromatografía , Cumarinas/química , Limoninas/química , Hipoclorito de Sodio/química
20.
J Toxicol ; 2014: 412437, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24734041

RESUMEN

Uncaria tomentosa is a medicinal plant used in folk medicine by Amazon tribes. In this study the constituents of aqueous extract of U. tomentosa bark were quantified by chromatographic technique and its lethal concentration 50 (48 h) in Hyphessobrycon eques was determined. The chromatography showed high levels of oxindole alkaloids, quinovic acid glycosides, and low molecular weight polyphenols. The CL50 48 h was 1816 mg/L. Fish showed behavior changes at concentrations above 2000 mg/L, accompanied by a significant decrease of dissolved oxygen. At the highest concentration 100% mortality was observed attributed to oxygen reduction by the amount of oxindole alkaloids, polyphenols accumulation of the extract in the gills, and the interaction of these compounds with dopamine. In conclusion, the aqueous extract of U. tomentosa did not alter the chemical components and it was shown that U. tomentosa has low toxicity to H. eques; therefore, it can be used safely in this species.

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