Antileishmanial activity and immunomodulatory effect of secosubamolide, a butanolide isolated from Nectandra oppositifolia (Lauraceae)

Visceral leishmaniasis is a complex neglected tropical disease caused by Leishmania donovani complex. Its current treatment reveals strong limitations, especially high toxicity. In this context, natural products are important sources of new drug alternatives for VL therapy. Therefore, the antileishmanial and immunomodulatory activity of compounds isolated from Nectandra oppositifolia (Lauraceae) was investigated herein. Methods: The n-hexane extract from twigs of N. oppositifolia were subjected to HPLC/HRESIMS and bioactivity-guided fractionation to afford compounds 1 and 2 which were evaluated in vitro against Leishmania (L.) infantum chagasi and NCTC cells. Results: The n-hexane extract displayed activity against L. (L.) infantum chagasi and afforded isolinderanolide E (1) and secosubamolide A (2), which were effective against L. (L.) infantum chagasi promastigotes, with IC50 values of 57.9 and 24.9 µM, respectively. Compound 2 was effective against amastigotes (IC50 = 10.5 µM) and displayed moderate mammalian cytotoxicity (CC50 = 42 µM). The immunomodulatory studies of compound 2 suggested an anti-inflammatory activity, with suppression of IL-6, IL-10, TNF with lack of nitric oxide. Conclusion: This study showed the antileishmanial activity of compounds 1 and 2 isolated from N. oppositifolia. Furthermore, compound 2 demonstrated an antileishmanial activity towards amastigotes associated to an immunomodulatory effect.(AU)

A semi-synthetic neolignan derivative from dihydrodieugenol B selectively affects the bioenergetic system of Leishmania infantum and inhibits cell division / A semi-synthetic neolignan derivative from dihydrodieugenol B selectively affects the bioenergetic system of Leishmania infantum and inhibits cell division

Leishmaniasis is a neglected disease that affects more than 12 million people, with a limited therapy. plant-derived natural products represent a useful source of anti-protozoan prototypes. In this work, four derivatives were prepared from neolignans isolated from the Brazilian plant Nectandra leucantha, and their effects against intracellular amastigotes of Leishmania (L.) infantum evaluated in vitro. IC50 values between 6 and 35 µM were observed and in silico predictions suggested good oral bioavailability, no pAINs similarities, and ADMet risks typical of lipophilic compounds. the most selective (sI > 32) compound was chosen for lethal action and immunomodulatory studies. this compound caused a transient depolarization of the plasma membrane potential and induced an imbalance of intracellular Ca2+, possibly resulting in a mitochondrial impairment and leading to a strong depolarization of the membrane potential and decrease of ATP levels. The derivative also interfered with the cell cycle of Leishmania, inducing a programmed cell death-like mechanism and affecting DNA replication. Further immunomodulatory studies demonstrated that the compound eliminates amastigotes via an independent activation of the host cell, with decrease levels of IL-10, TNF and MCP-1. Additionally, this derivative caused no hemolytic effects in murine erythrocytes and could be considered promising for future lead studies.

Dehydrodieugenol B derivatives as antiparasitic agents: Synthesis and biological activity against Trypanosoma cruzi

Chagas disease is a neglected protozoan disease that affects more than eight million people in developing countries. Due to the limited number and toxicity profiles of therapies in current use, new drugs are urgently needed. In previous studies, we reported the isolation of two related antitrypanosomal neo- lignans from Nectandra leucantha (Lauraceae). In this work, a semi-synthetic library of twenty-three neolignan derivatives was prepared to explore synthetically accessible structure activity relationships (SAR) against Trypanosoma cruzi. Five compounds demonstrated activity against trypomastigotes (IC50 values from 8 to 64 mM) and eight showed activity against intracellular amastigotes (IC50 values from 7 to 16 mM). Eighteen derivatives demonstrated no mammalian cytotoxicity up to 200 mM. The phenolic ac- etate derivative of natural dehydrodieugenol

Neolignans isolated from twigs of Nectandra leucantha Ness & Mart (Lauraceae) displayed in vitro antileishmanial activity

The therapeutic arsenal for the treatment of Leishmaniasis is limited and includes toxic compounds (antimonials, amphotericin B, pentamidine and miltefosine). Given these aspects, the search for new compounds based on floristic biodiversity is crucial. In the present work, we report the isolation, characterization and antileishmanial activity of six related neolignans (1­6) of bioactive extract from Nectandra leucantha (Lauraceae) twigs. Methods: Dried and powdered twigs of N. leucantha were exhaustively extracted using n-hexane. The crude extract was dereplicated by HPLC/HRESIMS and subjected to column chromatography to yield pure compounds 1­6. Their chemical structures were identified via NMR and comparison of obtained data with those previously published in the literature. Biological assays of compounds 1­6 and their respective monomers (eugenol and methyleugenol) were performed using promastigote and amastigote forms of Leishmania (L.) infantum. Results: Dereplication procedures followed by chemical characterization of isolated compounds by NMR enabled the identification of related neolignans 1­6. Neolignans 2, 4 and 6 showed potential against amastigote forms of L. (L.) infantum (EC50 values of 57.9, 67.7 and 13.7 µM, respectively), while compounds 1 and 3 were inactive. As neolignans 2­4 are chemically related, it may be suggested that the presence of the methoxyl group at C4 constitutes an important structural aspect to increase antileishmanial potential against amastigote forms. Compound 6, which consists of a methylated derivative of compound 5 (inactive) showed antileishmanial activity similar to that of the standard drug miltefosine (EC50 =16.9 µM) but with reduced toxicity (SI = 14.6 and 7.2, respectively). Finally, two related monomers, eugenol and methyleugenol, were also tested and did not display activity, suggesting that the formation of dimeric compounds by oxidative coupling is crucial for antiparasitic activity of dimeric compounds 2, 4 and 6. Conclusion: This study highlights compound 6 against L. (L.) infantum amastigotes as a scaffold for future design of new compounds for drug treatment of visceral leishmaniasis.(AU)

Exudates used as medicine by the "caboclos river-dwellers" of the Unini River, AM, Brazil – classification based in their chemical composition

Abstract Although the use of exudates in traditional medicine has been commonly observed during ethnopharmacological surveys, few records have been made concerning the scientific merits of these products. The aim of this study was to document ethnopharmacological data and to classify exudates used as medicine by the "caboclos" river-dwellers from the Unini River of Amazonas, Brazil, on chemical analyses basis. Using an ethnographic approach, indicated plants and their respective exudates were collected, identified and incorporated into herbarium of the National Institute of Amazonian Research. To classify these exudates, plant material was extracted using methanol, and obtained extracts were analyzed by Nuclear Magnetic Resonance and mass spectrometry aiming identification of main compounds. Fifteen exudates were indicated by "caboclos" river-dwellers as home remedies; among their therapeutic uses, inflammatory processes, culture-bound syndromes and respiratory diseases are most prominent. Based on their solubility and chemicals classes, fifteen exudates were classified into: latex (7), resins (5), sap (1), gum (1), oleoresin (1); and eleven of them have not been mentioned on pharmacological literature until this moment. The obtained results may contribute to chemical/pharmacological application of exudates from these species, several of which have been classically used in Brazilian folk medicine.

Flavonoids and fatty acids of Camellia japonica leaves extract

The ethanol extract from the leaves of Camellia japonica L., Theaceae, showed antiradical potential in the DPPH test using TLC plates (SiO2). Aiming the isolation of active compounds, this extract was partitioned between BuOH:H2O (1:1) and the two obtained phases were also evaluated to detection of antiradical activity. The active BuOH phase was fractionated in Sephadex LH-20 and silica (normal or reverse phase) to afford three aglycone flavonoids (quercetin, kaempferol and apigenin), which have been described in the C. japonica at first time, two glycosilated flavonoids (rutin and quercetrin), and a mixture of saturated fatty acids. The structures of isolated compounds were defined by NMR and GC/MS analyses.

Variação dos teores de constituintes voláteis de Cymbopogon citratus (DC) Staf, Poaceae, coletados em diferentes regiões do Estado de São Paulo / Variation in the amounts of volatile constituents of Cymbopogon citratus (DC) Staf, Poaceae, collected in different regions of São Paulo State

O óleo essencial extraído de Cymbopogon citratus (DC) Staf, Poaceae, é rico em citral sendo amplamente empregado na indústria química e farmacêutica. Os objetivos desse estudo foram avaliar o conteúdo de citral entre populações de C. citratus coletados em duas regiões diferentes (Ibiúna e Pindamonhangaba, Estado de São Paulo). O óleo essencial extraído de uma população cultivada em Pindamonhangaba-SP apresentou uma concentração alta de citral (aproximadamente 96,0 por cento), enquanto que o óleo extraído da população de Ibiúna-SP apresentou, além de citral, proporções elevadas de outro monoterpeno, o geraniol. Adicionalmente, os óleos essenciais obtidos desta população de C. citratus foram extraídos e analisados ao longo de 24 h (a cada 3 h), sendo que o teor de citral foi maior no período da noite, o que mostra a importância de estudos que avaliam as diferenças químicas associadas às mudanças circadianas. Os componentes dos óleos essenciais foram identificados por RMN de 13C, CG/EM e CG através do índice de Kovats.

The essential oil extracted from Cymbopogon citratus (DC) Staf, Poaceae, is rich in citral and has many applications in chemical and pharmaceutical industry. The aims of this study were evaluate the amount of citral in populations of C. citratus collected in two different regions (Ibiúna and Pindamonhangaba, São Paulo State). The essential oil extracted of a cultivated population in Pidamonhangaba-SP, showed a high content of citral (approximately 96.0 percent), while the essential oil from Ibiuna-SP, showed citral and high amounts of another monoterpene, geraniol. Additionally, the essential oils from this population of C. citratus were extracted and analyzed during 24 h (each 3 h), being the major concentration of citral in the night period, indicating that studies which evaluated the chemical differences associated to circadian changes. The components of essential oils were identified through 13C NMR, GC/MS, GC and Kovat's index.

Chemical composition and seasonal variation of the volatile oils from leaves of Michelia champaca L., Magnoliaceae / Composição química e variação sazonal dos óleos voláteis das folhas de Michelia champaca L., Magnoliaceae

The volatile oils from leaves of Michelia champaca L. collected bimonthly during one year (four times on the fifteenth day of January, March, May, July, September, and November - 2004) were subjected to GC/FID and GC-MS analysis, from which thirteen components were identified. Additionally, part of the oil obtained from January collection was subjected to fractionation over silica gel soaked with AgNO3 to afford five of the main sesquiterpenes (β-elemene, β-caryophyllene, α-humulene, β-selinene, and α-cadinol). The obtained data showed a significative variation in the proportions of the components, which could be associated to climatic parameters in each collection periods.

Os óleos voláteis das folhas de Michelia champaca L., coletadas bimestralmente ao longo de um ano (quatro vezes no décimo quinto dia de janeiro, março, maio, julho, setembro e novembro de 2004), foram submetidos à análise por CG/DIC e CG-EM, de onde foram identificados treze componentes. Adicionalmente, parte do óleo obtido na coleta de janeiro foi submetida a fracionamento em gel de sílica impregnada com AgNO3 fornecendo cinco dos principais sesquiterpenos (β-elemeno, β-cariofileno, α-humuleno, β-selineno e α-cadinol). Os dados obtidos mostram uma variação significativa na proporção dos componentes, a qual pode estar associada a parâmetros microclimáticos em cada período de coleta.

Constituintes químicos das folhas de Murraya paniculata (Rutaceae) / Chemical constituents from leaves of Murraya paniculata (Rutaceae)

A separação cromatográfica do extrato hexânico e da fase em CH2Cl2 do extrato etanólico das folhas de Murraya paniculata resultou no isolamento de um triterpeno (24-metileno-cicloartan-3β-ol), um fenilpropanóide (cafeato de metila) e sete cumarinas preniladas [isomeranzina, acetato de murranganona, murrayatina, murrangatina, hidrato de meranzina, febalosina e murranganona]. Dentre as substâncias isoladas, as cumarinas foram detectadas anteriormente em M. paniculata ao passo que 24-metileno-cicloartan-3β-ol e cafeato de metila estão sendo descritos pela primeira vez no gênero Murraya. Os extratos e frações além das substâncias puras foram submetidos à avaliação do potencial antimicrobiano frente à Staphylococcus aureus e Escherichia coli indicando que somente a cumarina hidrato de meranzina mostrou fraca atividade.

Chromatographic separation of the hexane extract and the CH2Cl2 phase from the ethanol extract from leaves of Murraya paniculata yielded one triterpenoid (24-methylene-cycloartan-3β-ol), one phenylpropanoid (methyl caffeate) and seven coumarins [isomeranzine, murranganone acetate, murrayatine, murrangatine, meranzine hydrate, phebalosine and murranganone]. All the isolated coumarins were previously obtained from M. paniculata while 24-methylene-cycloartan-3β-ol and methyl caffeate have been described for first time in the Murraya genus. The crude extracts, fractions and pure substances were submitted to evaluation of antimicrobial potential against Staphylococcus aureus and Escherichia coli which indicated that the coumarin meranzine hydrate showed weak activity.

Aplicação de técnicas cromatográficas e espectrométricas como ferramentas de auxílio na identificação de componentes de óleos voláteis / Use of chromatographic and spectrometric techniques to help the identification of volatile compounds

A metodologia usual aplicada para análise de óleos voláteis, tais como CG, CG-EM, índice de Kovats e, em alguns casos, sistemas computacionais especialistas, não permitem a identificação de compostos desconhecidos os quais devem ser isolados para que tenham suas estruturas moleculares elucidadas. Essa limitação é ainda maior quando tais óleos apresentam potencial biológico uma vez que existe grande dificuldade no isolamento das substâncias ativas, as quais devem ser obtidas em seu estado puro para avaliação da atividade. Assim, este trabalho descreve uma metodologia de separação não usual (cromatografia rápida em sílica e sílica impregnada com AgNO3) associada a técnicas espectrométricas (EM, RMN de ¹H e RMN de 13C) as quais permitiram a purificação e caracterização de compostos de óleos voláteis contendo estruturas ainda não conhecidas e/ou biologicamente ativas.

The usual techniques applied for analyzing the chemical constitution of volatile oils, such as GC, GC-MS, Kovats Index and, in some cases, specialist computational systems, do not allow the identification of the unknown or biologically active compounds which must be isolated in order to have their molecular structures elucidated. This problem is higher if the oils present biological potential, which will induce in the isolation of active substances, once these substances must be obtained in their pure state to activity evaluation. Thus, this paper describes an unusual chromatographic separation (flash chromatography on SiO2 and SiO2/AgNO3) associated to spectrometric techniques (MS, ¹H NMR and 13C NMR), which lead to the purification and structural elucidation of the unpublished and/or biologically active constituents from volatile oils.

Sesquiterpenos e hidrocarbonetos dos frutos de Xylopia emarginata (Annonaceae) / Sesquiterpenes and hydrocarbons from Xylopia emarginata (Annonaceae) fruits

O extrato hexânico dos frutos de Xylopia emarginata foi particionado entre hexano e MeOH/H2O. A fase hidroalcoólica foi submetida à separação cromatográfica fornecendo quatro sesquiterpenos: óxido de cariofileno, espatulenol, 1beta,6alfa-diidroxi-4(15)-eudesmeno e 4-hidroxi-1,15-peróxieudesmano. A fase hexânica foi fracionada através de cromatografia em coluna fornecendo dois hidrocarbonetos (nonadecano e 1-nonadeceno) e uma cetona alifática (hentriacontan-16-ona). As estruturas dos compostos isolados foram estabelecidas através de análise espectroscópica, principalmente RMN e EM.

The hexane extract from Xylopia emarginata fruits was partitioned between hexane and MeOH/H2O. The hydro-alcoholic phase was submitted to chromatographic separation to afford four sesquiterpenes: caryophyllene oxide, spathulenol, 1beta,6alpha-dihydroxy-4(15)-eudesmene and 4-hydroxy-1,15-peroxy-eudesmane. The hexane phase was fractioned in column chromatography to afford two hydrocarbons (nonadecane and 1-nonadecene) and one aliphatic ketone (hentriacontan-16-one). The structures of the isolated compounds were established by spectral data analysis, mainly NMR and MS.