The key step in the chemoenzymatic synthesis of apremilast was to produce the chiral alcohol (R)-1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethanol, (R)-3. Two enzymatic approaches were evaluated to obtain (R)-3, one using ketoreductases and the other lipases. Bioreduction of 1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethanone (2), using ketoreductase KRED-P2-D12, led to (R)-3 with 48% conversion and 93% enantiomeric excess (ee). Kinetic resolution of rac-1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl acetate (rac-4), via hydrolysis reaction, with 20% of n-butanol, catalyzed by lipase from Aspergillus niger yielded (R)-3 with > 99% ee, 50% conversion and E-value (enantiomeric ratio) > 200. The reaction between enantiomerically pure (R)-3 and 4-acetylamino-isoindol-1,3-dione (8) afforded apremilast in 65% yield and 67% ee.
In order to produce bioactive derivatives of carvacrol and thymol, nine derivatives of each compound were prepared through modifications the phenolic hydroxyl group. The structures of compounds were confirmed by spectral data from MS, IR and NMR. Carvacrol, thymol and derivatives were submitted to the evaluation of the inhibition of the enzyme acetylcholinesterase, using a colorimetric method in which the inhibition of the enzyme is measured by coloration, and larvicidal activity against Aedes aegypti. Derivatives carvacryl acetate-1b and thymyl hexanoate-2b showed the best results for the inhibition of the acetylcholinesterase enzyme, and for the larvicidal activity the derivatives 1a, 1b, 1c, 3h, 2a, 2b, 2c and 4h showed positive results, emphasizing compound thymyl 4-methoxybenzoate-4h which showed LC50 values of 23.60 ppm, considered a very good result.
Four new alkaloids, Brazoides A-D, together with three known compounds squalene, β-sitosterol and lupeol, were isolated from leaves of Justicia gendarussa. These structures were established by spectrometric techniques, mainly high-resolution electrospray ionization mass spectrometry (HRESIMS) and 1D and 2D nuclear magnetic resonance (NMR), including comparative analysis with literature values. Structural determination of the compounds, Brazoides A-D, was strengthened by molecular modeling and density functional theory (DFT) calculations to predict the NMR data and compare with the experimental NMR values of these natural products. The new compounds were tested against three human cancer cell lines (glioblastoma, prostate and colon), but none exhibited activity.
Various vegetables as biological catalysts were evaluated in enantioselective reduction of carbonyl compounds. The stereoselectivity of the process was in agreement with Prelog's rule for twelve of the vegetables, whereas okra and green peppers formed anti-Prelog products. Zingiber officinale exhibited the best results with 30% conversion and 89% ee. The parameters of the reaction such as time, solvent and other substrates investigated, as well as the specie, showed good chemo- and enantioselectivity.
The lipase-catalyzed synthesis of thiamphenicol derivatives has been studied through complementary acylation and hydrolytic approaches, finding Candida antarctica lipase B as the most efficient biocatalyst for the selective modification of both thiamphenicol and thiamphenicol diacetate, respectively. The best results have been obtained using acylation reactions with different vinyl esters of variable length, yielding the corresponding 3'-monoesters with excellent yields and in short reaction times. The conditions have been analyzed in terms of substrate concentration, enzyme loading and type of acyl donor. The reuse of the enzyme for five-times without significant loss of the activity has also been demonstrated. Alternatively, the hydrolytic approach has allowed the preparation of some 1'-monoesters in good yields, although the reactivity and selectivity levels were lower than the ones achieved for the complementary acetylation reaction.
A síntese de derivados do tianfenicol, catalisada por lipases, foi investigada através da realização das reações de acilação e de hidrólise, como abordagens complementares, sendo a lipase Candida antarctica B o biocatalisador mais eficiente para as modificações seletivas de ambos, o tianfenicol e o correspondente diacetato do tianfenicol, respectivamente. Os melhores resultados foram obtidos nas reações de acilação com diferentes ésteres vinílicos, contendo cadeias carbônicas de comprimento variável, levando aos correspondentes 3'-monoésteres com excelentes rendimentos e em tempos reacionais curtos. As condições reacionais foram analisadas em termos de concentração de substrato, carga de enzima e tipo de doador de acila. Foi demonstrado o reuso da enzima por cinco vezes sem perda significativa de atividade. Alternativamente, a abordagem hidrolítica propiciou a preparação de alguns 1'-monoésteres em bons rendimentos, ainda que os níveis de reatividade e seletividade foram mais baixos que os obtidos na reação complementar de acetilação.
OBJECTIVE: The present study aimed to measure in-vivo the depth and the percentage of testosterone in human skin. METHOD: Two healthy young Brazilian volunteers were evaluated through a Confocal Raman Spectroscopy probe on the right volar forearm. Testosterone spectroscopy of was performed on the Stratum Corneum, Viable Epidermis and Dermis; the percentage concentration of testosterone was compared between the baseline and one hour after local application of a transdermal nanostructured testosterone (5%) formulation. RESULTS: To the best of our knowledge, this is the first time that the depth and percentage of testosterone has been evaluated non-invasively in-vivo. No adverse events were attributed to this protocol. The method is effective in differentially measuring testosterone in the skin layers. CONCLUSION: This protocol may serve as a good choice for rapid hormone quantification for forensic or medical purposes.
RESUMO OBJETIVO: O presente estudo teve como objetivo avaliar in-vivo a profundidade e a porcentagem de testosterona na pele humana. MÉTODO: Dois jovens voluntários brasileiros saudáveis foram avaliadas através de uma sonda confocal de Espectroscopia Raman na face volar do antebraço direito. A espectroscopia de testosterona foi realizada no estrato córneo, na epiderme viável e na derme; a concentração percentual de testosterona foi comparada entre a linha de base e uma hora após a aplicação transdérmica de uma formulação de testosterona nanoestruturada (5%). RESULTADOS: Tanto quanto sabemos, esta é a primeira vez que a profundidade e a porcentagem de testosterona foi avaliada de forma não invasiva in-vivo. Nenhum evento adverso foi associado a esse protocolo. O método é eficaz na medição diferencial da testosterona nas camadas da pele. CONCLUSÃO: Este protocolo pode servir como uma boa alternativa para a rápida quantificação hormonal com finalidade forense ou médica.
Stemodinol, a new natural compound, together with known compounds including jaceidin, stemodin, stemodinoside B, isocrenatoside, verbascoside, crenatoside, and isoverbascoside, were isolated from Stemodia maritima Linn. The antioxidant (DPPH method) and antimicrobial activities of stemodin, stemodinoside B, and crenatoside were investigated. Among the components tested, only crenatoside isolated from the roots showed a high antioxidant power. Stemodin and stemodinoside B exhibited antibacterial activities.
The chemical investigation of the stems and branches of Macroptilium lathyroides led to the isolation of a mixture of β-sitosterol and stigmasterol. The extracts from the roots allowed the isolation of lasiodiplodin, a mixture of stigmast-4-en-6β-ol-3-one and stigmast-4,22-dien-6β-ol-3-one, de-O-methyllasiodiplodin, genistein and lupinalbin A. The structures of the isolated compounds were assigned on the basis of their NMR data, including comparison of their spectral data with values described in the literature. The antibacterial activity of crude extracts from stems, branches and roots was evaluated. This is the first report involving the chemical investigation of this species.
The formation of paramagnetic species from oncocalyxone A in aprotic medium was confirmed by performing in situ electrochemical-electron spin resonance (E-ESR) experiments. The high delocalization of the radical generated at the first reduction potential is clearly evidenced by the hyperfine coupling of H-9 with the larger coupling constant, besides the couplings at the H-3 (close to quinone) and H-7 (far from the quinone nucleus) positions. In protic medium, together with pH dependence experiments, oncocalyxone A showed to be DNA-reactive through experiments with DNA sensors. Its reaction with N-acetylcysteine, with structural characterization of the addition products, proved its ability as Michael acceptor. Both aspects are important in terms of biological/pharmacological activities and indicate the present models as important tools in the screening of biologically active compounds.
A formação de espécies paramagnéticas a partir da oncocalixona A em meio aprótico foi confirmada pela realização de experimentos eletroquímicos in situ em conjunto com ressonância de spin eletrônico (E-ESR). A alta deslocalização do radical gerado no primeiro potencial de redução está claramente evidenciada pelo acoplamento hiperfino do H-9 com a maior constante de acoplamento, além dos acoplamentos nas posições H-3 (próximo à quinona) e H-7 (distante do núcleo quinônico). Em meio prótico, além dos experimentos de dependência com o pH, oncocalixona A mostrou-se DNA-reativa por meio de experimentos eletroquímicos com sensores de DNA. Sua reação com N-acetilcisteína, com caracterização estrutural dos produtos de adição, evidencia sua habilidade como aceptor de Michael. Ambos os aspectos são importantes em termos de atividades biológicas/farmacológicas e indicam os presentes modelos como ferramentas importantes na avaliação de compostos biologicamente ativos.
Analysis of essential oil from fresh leaves of Capraria biflora allowed identification of fourteen essential oil constituents among which thirteen are sesquiterpene compounds, and α-humulene (43.0%) the major constituent. The essential oil was tested for larvicidal activity against Aedes aegypti showing good activity, with LC50 73.39 µg/mL (2.27 g/mL). Chromatographic studies of extracts from roots and stems allowed the isolation of five compounds: naphthoquinone biflorin, sesquiterpene caprariolide B, the steroid β-sitosterol, the carbohydrate D-mannitol and iridoid myopochlorin first reported in the species C. biflora. The structures of compounds were characterized by spectroscopic data, IR, MS, NMR13C, NMR¹H, NOE, HSQC and HMBC.
The chemical investigation of the ethanol extracts of stems, roots and leaves of Lippia sidoides led to the isolation of: steroid β-sitosterol, naphthoquinone tecomaquinone, monoterpene carvacrol, flavonoid 4',5,7-trihydroxyflavanone (naringenin), 3',4',5,7-tetrahydroxyflavanone and 4',5,7-trihydroxy-6-methoxyflavone flavonoids mixture, and 3,4,4',6'-tetrahydroxydihydrochalcone-2'-O-β-D-glucopyranoside and 4,4',6'-trihydroxydihydrochalcone-2'-O- β-D-glucopyranoside dihydrochalcones mixture. Their structures were characterized on the basis of spectral data, mainly ¹H and 13C NMR (1D and 2D) and mass spectra. The ethanol extract and isolated compounds were evaluated for their antioxidative properties using the method of inhibition of free radical DPPH (2,2-diphenyl-1-picrylhydrazyl).
The reactivity and stereoselectivity showed by a new strain of Candida tropicalis in the reduction of prochiral ketones have been compared with the ones previously attained in our laboratory using microorganisms from the Brazilian biodiversity. In this manner, Candida tropicalis has demonstrated its versatility as stereoselective agent in the bioreduction of a series of aromatic ketones. These prochiral compounds were converted into their corresponding optically alcohols with moderate to excellent stereopreference depending on the substrate structure. Among ketones tested, nitroacetophenones were enzymatically reduced to enantiopure (S)-alcohol with complete conversion.
A reatividade e estereosseletividade apresentadas por uma nova cepa de Candida tropicalis na redução de cetonas pró-quirais foram comparadas com cepas de microrganismos, estudadas em nosso laboratório, provenientes da biodiversidade brasileira. Neste caso, Candida tropicalis demonstrou-se como um agente redutor versátil e estereosseletivo na biorredução de uma série de cetonas aromáticas. Estes compostos pró-quirais foram convertidos aos correspondentes álcoois opticamente ativos com moderada a excelente estereopreferência dependendo da estrutura do substrato. Entre as cetonas utilizadas, as nitroacetofenonas foram enzimaticamente reduzidas aos correspondentes (S)-álcoois enantiopuros com completa conversão.
An analysis of the constituents of coconut (Cocos nucifera L.) water from two fruit varieties (green and yellow) by hydrodistillation and solvent extraction showed the presence of alcohols, ketones, thiols, carboxylic acids, phenols, and esters. Substantial antioxidant activity was observed, using the DPPH assay, for the samples obtained by hydrodistillation and petroleum ether extraction of both coconut varieties.
Uma análise dos componentes da água-de-coco (Cocos nucifera L.) de duas variedades da fruta (verde e amarelo) por hidrodestilação e extração com solvente, mostrou a presença de álcoois, cetonas, tióis, ácidos carboxílicos, fenóis, e ésteres. Significativa atividade antioxidante foi observada, usando o método DPPH, para as amostras obtidas por hidrodestilação e extração de éter de petróleo para ambas as variedades do coco.
The aim of present study was to describe the chemical composition of the essential oils from the leaf and stem of Rollinia leptopetala R. E. Fries (Annonaceae) and to evaluate the larvicidal activities of these essential oils, of the methanol extract from roots of this plant and of the oxoaporphine alkaloid, liriodenine (1) against the third-instar of Aedes aegypti larvae. The methanol extract from the roots showed larvicidal activity with LC50 64.6 ± 1.5 ppm. Higher activity was observed for the isolated alkaloid liriodenine (1), LC50 3.6 ± 0.4 ppm. The essential oils from the leaves and stems, also exhibited larvicidal activity with LC50 104.7 ± 0.2 and 34.7 ± 0.3 ppm, respectively. These results suggest R. leptopetala as a source of natural larvicidal compounds. This is the first report about the chemical composition and larvicidal activity of the leaf and stem essential oils of R. leptopetala.
No presente trabalho descreve-se a composição química dos óleos essenciais de Rollinia leptopetala R.E. Fries (Annonaceae) e as atividades larvicidas dos óleos essenciais, do extrato metanólico das raízes desta espécie e do alcalóide oxoaporfinico, liriodenina (1), frente às larvas no terceiro estágio do mosquito Aedes aegypti. O extrato metanólico mostrou-se ativo com CL50 64,6 ± 1,5 ppm e uma forte atividade foi exibida para o composto (1), CL50 3,6 ± 0,4 ppm. Os óleos essenciais das folhas e galhos também mostraram atividade com CL50 104,7 ± 0,2 and 34,7 ± 0,3 ppm, respectivamente. Estes dados sugerem que R. leptopetala é fonte potencial de larvicidas naturais. A composição química do óleo essencial e as atividades descritas são comunicadas pela primeira vez.
Six known alkaloids iboga type and the triterpen α- and β-amyrin acetate were isolated from the roots and stems of Peschiera affinis. Their structures were characterized on the basis of spectral data mainly NMR and mass spectra. 1D and 2D NMR spectra were also used to unequivocal ¹H and 13C chemical shift assignments of alkaloids. The ethanolic extract of roots, alkaloidic and no-alkaloidic fractions and iso-voacristine hydroxyindolenine and voacangine were evaluated for their antioxidative properties using an autographic assay based on β-carotene bleaching on TLC plates, and also spectrophotometric detection by reduction of the stable DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical.