RESUMO
A new prenylated dihydrochalcone, 2',4'-dihydroxy-4-methoxy-3'-prenyldihydrochalcone (1), along with two known compounds, 2',4',4-trihydroxy-3'-prenylchalcone (2) and 2',4-dihydroxy-3',4'-(2,2-dimethylchromene)chalcone (3) were isolated from the leaves of Artocarpus lowii. The structures of 1-3 were elucidated by spectroscopic methods and by comparison with data reported in the literature. Compounds 1-3 showed strong free radical scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) measured by electron spin resonance (ESR) spectrometry.
Assuntos
Artocarpus/química , Chalconas/farmacologia , Extratos Vegetais/farmacologia , Chalconas/química , Chalconas/isolamento & purificação , Espectroscopia de Ressonância de Spin Eletrônica , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/isolamento & purificação , Sequestradores de Radicais Livres/farmacologia , Radicais Livres/metabolismo , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Folhas de Planta , Análise EspectralRESUMO
Bioassay-guided chromatographic purification of the antitubercular chloroform extract of Pandanus tectorius Soland. var. laevis leaves afforded a new tirucallane-type triterpene, 24,24-dimethyl-5 beta-tirucall-9(11),25-dien-3-one (1), squalene and a mixture of the phytosterols stigmasterol and beta-sitosterol. Microplate Alamar Blue Assay (MABA) showed that 1 inhibited the growth of Mycobacterium tuberculosis H(37)Rv with a MIC of 64 microg/mL, while squalene and the sterol mixture have MICs of 100 and 128 microg/mL, respectively.
Assuntos
Antituberculosos/farmacologia , Pandanaceae/química , Fitosteróis/farmacologia , Folhas de Planta/química , Triterpenos/farmacologia , Antituberculosos/química , Antituberculosos/isolamento & purificação , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/crescimento & desenvolvimento , Fitosteróis/química , Fitosteróis/isolamento & purificação , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Sitosteroides/química , Sitosteroides/isolamento & purificação , Sitosteroides/farmacologia , Esqualeno/química , Esqualeno/isolamento & purificação , Esqualeno/farmacologia , Estigmasterol/química , Estigmasterol/isolamento & purificação , Estigmasterol/farmacologia , Triterpenos/química , Triterpenos/isolamento & purificaçãoRESUMO
Four new gelsedine-type indole alkaloids (1-4) were isolated from the leaves of Gelsemium elegans, together with 11 known alkaloids. The structures were determined as 14-acetoxygelsenicine (1), 14-acetoxy-15-hydroxygelsenicine (2), 14-hydroxy-19-oxogelsenicine (3), and 14-acetoxygelselegine (4), respectively, by spectroscopic analysis. The cytotoxic effects of 14 Gelsemium alkaloids including two new compounds (1, 2) were evaluated using the A431 human epidermoid carcinoma cell line. Of these, the gelsedine-type alkaloids 14-acetoxy15-hydroxygelsenicine (2) [corrected] 14,15-dihydroxygelsenicine (5), gelsedine (7), and gelsemicine (8) showed potent cytotoxic effects.
Assuntos
Alcaloides , Gelsemium/química , Alcaloides Indólicos , Plantas Medicinais/química , Alcaloides/química , Alcaloides/classificação , Alcaloides/isolamento & purificação , Alcaloides/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Alcaloides Indólicos/química , Alcaloides Indólicos/classificação , Alcaloides Indólicos/isolamento & purificação , Alcaloides Indólicos/farmacologia , Japão , Estrutura Molecular , Oxindóis , Células Tumorais CultivadasRESUMO
Several species of the genus Artocarpus (Moraceae) have been investigated in our laboratories during the last decade. Over 60 phenolic constituents have been discovered and characterized, including 27 new compounds from 13 Indonesian taxa of Artocarpus, namely A. champeden, A. lanceifolius, A. teysmanii, A. scortechinii, A. rotunda, A. maingayi, A. kemando, A. bracteata, A. altilis, A. fretessi, A. gomezianus, A. reticulatus and A. glaucus. The principal and the most pronounced features of these phenolic constituents are the assembly of an isoprenyl substituent at C-3 of a flavone skeleton by closure of an ether bridge or a carbon-carbon linkage with the B ring of the skeleton, which may further rearrange into xanthone to produce various classes of natural products. The structures of the new and unusual natural products are presented. Many of the metabolites also exhibit cytotoxic effect against murine leukemia P388 cells.
RESUMO
Mitragynine is an indole alkaloid isolated from the Thai medicinal plant Mitragyna speciosa that is reported to have opioid agonistic properties. The 9-demethyl analogue of mitragynine, 9-hydroxycorynantheidine, is synthesized from mitragynine. 9-Hydroxycorynantheidine inhibited electrically stimulated guinea-pig ileum contraction, but its maximum inhibition was weaker than that of mitragynine and its effect was antagonized by naloxone, suggesting that 9-hydroxycorynantheidine possesses partial agonist properties on opioid receptors. Receptor binding assays revealed that 9-hydroxycorynantheidine has high affinity for mu-opioid receptors. In an assay of the guinea-pig ileum, naloxone shifted the concentration-response curves for [D-Ala(2), N-MePhe(4), Gly-ol(5)]-enkephalin (DAMGO), (5alpha,7alpha,8beta)-(+)-N-Methyl-N-[7-(1-pyrrolidinyl)-1-oxaspiro[4.5]dec-8-yl]-benzeneacetamide (U69593) and 9-hydroxycorynantheidine to the right in a competitive manner. The pA(2) values of naloxone against 9-hydroxycorynantheidine and DAMGO were very similar, but not that against U69593. As indicated by the two assay systems, the opioid effect of 9-hydroxycorynantheidine is selective for the mu-opioid receptor. 9-Hydroxycorynantheidine shifted the concentration-response curve for DAMGO slightly to the right. Pretreatment with the mu-opioid selective and irreversible antagonist beta-funaltorexamine hydrochloride (beta-FNA) shifted the concentration-response curve for DAMGO to the right without affecting the maximum response. On the other hand, beta-FNA did not affect the curve for 9-hydroxycorynantheidine, but decreased the maximum response because of the lack of spare receptors. These studies suggest that 9-hydroxycorynantheidine has partial agonist properties on mu-opioid receptors in the guinea-pig ileum.
Assuntos
Íleo/efeitos dos fármacos , Alcaloides Indólicos/farmacologia , Receptores Opioides mu/agonistas , Alcaloides de Triptamina e Secologanina/farmacologia , Animais , Ligação Competitiva , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Estimulação Elétrica , Cobaias , Íleo/metabolismo , Técnicas In Vitro , Masculino , Estrutura Molecular , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Músculo Liso/metabolismo , Ligação Proteica , Ensaio Radioligante , Alcaloides de Triptamina e Secologanina/químicaRESUMO
Two new monoterpene glucosides, demethylsecologanol and 3'''-O-glucosylsenburiside II, were isolated from Ophiorrhiza liukiuensis (Rubiaceae) together with 23 known compounds, including camptothecins and beta-carboline-type alkaloids. Their structures were determined by spectroscopic analysis.
Assuntos
Camptotecina/análogos & derivados , Camptotecina/química , Glucosídeos/química , Monoterpenos/química , Rubiaceae/química , Isótopos de Carbono , Glucosídeos/isolamento & purificação , Espectroscopia de Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/normas , Espectrometria de Massas , Conformação Molecular , Monoterpenos/isolamento & purificação , Padrões de Referência , Espectrofotometria UltravioletaRESUMO
7-Hydroxymitragynine is a potent opioid analgesic alkaloid isolated from the Thai medicinal herb Mitragyna speciosa. In the present study, we investigated the opioid receptor subtype responsible for the analgesic effect of this compound. In addition, we tested whether development of tolerance, cross-tolerance to morphine and naloxone-induced withdrawal signs were observed in chronically 7-hydroxymitragynine-treated mice. Subcutaneous (s.c.) administration of 7-hydroxymitragynine produced a potent antinociceptive effect mainly through activation of mu-opioid receptors. Tolerance to the antinociceptive effect of 7-hydroxymitragynine developed as occurs to morphine. Cross-tolerance to morphine was evident in mice rendered tolerant to 7-hydroxymitragynine and vice versa. Naloxone-induced withdrawal signs were elicited equally in mice chronically treated with 7-hydroxymitragynine or morphine. 7-Hydroxymitragynine exhibited a potent antinociceptive effect based on activation of mu-opioid receptors and its morphine-like pharmacological character, but 7-hydroxymitragynine is structurally different from morphine. These interesting characters of 7-hydroxymitragynine promote further investigation of it as a novel lead compound for opioid studies.
Assuntos
Analgésicos , Mitragyna/efeitos adversos , Mitragyna/química , Alcaloides de Triptamina e Secologanina/efeitos adversos , Alcaloides de Triptamina e Secologanina/farmacologia , Síndrome de Abstinência a Substâncias/psicologia , Analgésicos Opioides/farmacologia , Animais , Relação Dose-Resposta a Droga , Tolerância a Medicamentos , Injeções Subcutâneas , Masculino , Camundongos , Modelos Moleculares , Morfinanos/farmacologia , Morfina/antagonistas & inibidores , Morfina/farmacologia , Naloxona/farmacologia , Naltrexona/análogos & derivados , Naltrexona/farmacologia , Antagonistas de Entorpecentes/farmacologia , Medição da Dor/efeitos dos fármacos , Tempo de Reação/efeitos dos fármacos , Alcaloides de Triptamina e Secologanina/química , TailândiaRESUMO
A new oleanane-triterpene, 3beta-acetoxy-11alpha-benzoyloxy-13beta-hydroxyolean-12-one (1), was isolated along with a known quinone-methide triterpene, pristimerin (2), from the root bark of Siphonodon celastrineus Griff., a Thai medicinal plant of the family Celastraceae. Their structures were determined based on spectroscopic analysis.
Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Casca de Planta/química , Plantas Medicinais/química , Triterpenos/isolamento & purificação , Espectroscopia de Ressonância Magnética , Triterpenos/química , Triterpenos/farmacologiaRESUMO
Recently, we found that mitragynine, a major constituent of Mitragyna speciosa, has an opioid agonistic activity, but its weak potency could not explain the opium-like effect of this plant. In the present study, bioassay-guided fractionation of the crude extract of the leaves of M. speciosa was carried out to search for potent opioid agonists other than mitragynine. Opioid agonistic activities were evaluated using twitch contraction induced by electrical stimulation in guinea-pig ileum. The crude extract of M. speciosa inhibited the twitch contraction in a concentration-dependent manner. The inhibition was reversed by naloxone. The opioid effect was detected only in the crude base fraction, which was followed by the isolation of five indole alkaloids. Among these alkaloids, 7-hydroxymitragynine showed the most potent opioid effect on the electrically-stimulated contraction (pD (2) = 8.38 +/- 0.12). The potency, calculated using pD (2) values, was 30- and 17-fold higher than that of mitragynine and morphine, respectively. Antagonism of naloxone on concentration-response curves for 7-hydroxymitragynine confirmed its opioid effect. These results suggest that the opioid effect of M. speciosa is mostly based on the activity of 7-hydroxymitragynine.
Assuntos
Analgésicos Opioides/farmacologia , Mitragyna , Fitoterapia , Receptores Opioides/efeitos dos fármacos , Alcaloides de Triptamina e Secologanina/farmacologia , Analgésicos Opioides/administração & dosagem , Analgésicos Opioides/uso terapêutico , Animais , Relação Dose-Resposta a Droga , Estimulação Elétrica , Cobaias , Íleo/efeitos dos fármacos , Alcaloides Indólicos/administração & dosagem , Alcaloides Indólicos/farmacologia , Alcaloides Indólicos/uso terapêutico , Masculino , Medicina Tradicional , Contração Muscular/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Folhas de Planta , Alcaloides de Triptamina e Secologanina/administração & dosagem , Alcaloides de Triptamina e Secologanina/uso terapêutico , TailândiaRESUMO
A new alkaloid, lycoposerramine-B (1), containing an oxime function, was isolated from the club moss Lycopodium serratum Thunb. The structure of 1 was elucidated by spectroscopic analysis, including J-resolved HMBC spectroscopy, and confirmed by its synthesis from the known alkaloid, serratinine (3).
Assuntos
Alcaloides/síntese química , Compostos Heterocíclicos com 3 Anéis/síntese química , Indolizinas/química , Lycopodium/química , Oximas/química , Oximas/síntese química , Alcaloides/química , Alcaloides/isolamento & purificação , Configuração de Carboidratos , Compostos Heterocíclicos com 3 Anéis/química , Espectroscopia de Ressonância Magnética , Estrutura MolecularRESUMO
Rhynchophylline and isorhynchophylline are major tetracyclic oxindole alkaloid components of Uncaira species, which have been long used as medicinal plants. In this study we examined the protective effects of rhynchophylline and isorhynchophylline on in vitro ischemia-induced neuronal damage in the hippocampus and interaction of these alkaloids with neurotransmitter receptors in a receptor expression model of Xenopus oocytes. In vitro ischemia was induced by exposing the hippocampal slices to oxygen- and D-glucose-deprived medium over 8 min. The resultant neuronal damage was elucidated as deterioration of population spike (PS) amplitudes evoked trans-synaptically by electrical stimulation of Schaffer collaterals and recorded in the CA1 area. Rhynchophylline and isorhynchophylline, as well as the N-methyl-D-aspartate (NMDA) antagonist (+/-)-2-amino-5-phosphono-valeric acid (APV), the muscarinic M1 receptor antagonist pirenzepine, and the 5-HT2 receptor antagonist ketanserin, attenuated the in vitro ischemia-induced neuronal damage in a concentration-dependent manner. There was no difference in the extent of protection against the neuronal damage between rhynchophylline and isorhynchophylline treatment. In Xenopus oocytes expressing the rat brain receptors encoded by total RNA, both rhynchophylline and isorhynchophylline reduced muscarinic receptor- and 5-HT2 receptor-mediated current responses in a competitive manner. Together with our previous findings that rhynchophylline and isorhynchophylline have a non-competitive antagonistic effect on the NMDA-type ionotropic glutamate receptors, the present results suggest that these alkaloids exert their protective action against ischemia-induced neuronal damage by preventing NMDA, muscarinic M1, and 5-HT2 receptors-mediated neurotoxicity during ischemia.
Assuntos
Alcaloides/farmacologia , Isquemia Encefálica , Hipocampo/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Uncaria/química , Valina/análogos & derivados , Animais , Isquemia Encefálica/prevenção & controle , Hipóxia Celular/efeitos dos fármacos , Hipóxia Celular/fisiologia , Hipocampo/patologia , Técnicas In Vitro , Alcaloides Indólicos , Ketanserina/farmacologia , Masculino , Potenciais da Membrana/efeitos dos fármacos , Neurônios/patologia , Oócitos/efeitos dos fármacos , Oxindóis , Pirenzepina/farmacologia , Ratos , Ratos Wistar , Valina/farmacologia , Xenopus laevisRESUMO
A new oleanan-type triterpene and three new cincholic acid glycosides were isolated from Peruvian "Una de Gato" (Cat's claw, plant of origin: Uncaria tomentosa), a traditional herbal medicine in Peru. Their structures were determined by spectroscopic analysis.
Assuntos
Unha-de-Gato , Glicosídeos/química , Ácido Oleanólico/análogos & derivados , Ácido Oleanólico/química , Triterpenos/química , Glicosídeos/isolamento & purificação , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Ácido Oleanólico/isolamento & purificação , Peru , Extratos Vegetais/química , Plantas Medicinais/química , Triterpenos/isolamento & purificaçãoRESUMO
Two new tryptamine-related alkaloids, psychotrimine and psychopentamine, were isolated from the leaves of Psychotria rostrata, and their novel structures were elucidated on the basis of spectroscopic analyses.
Assuntos
Alcaloides Indólicos/isolamento & purificação , Plantas Medicinais/química , Psychotria/química , Alcaloides Indólicos/química , Conformação Molecular , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Folhas de Planta/químicaRESUMO
A new yohimbine-type indole alkaloid (1). was isolated from the stem bark of Mitragyna africanus (WILLD.) collected in Nigeria, along with known seven Corynanthe-type oxindole alkaloids, two secoiridoids, three lignans, and a quinovic acid derivative. Their structures were elucidated by spectroscopic analyses.
Assuntos
Alcaloides Indólicos/isolamento & purificação , Mitragyna/química , Plantas Medicinais/química , Ioimbina/isolamento & purificação , Alcaloides Indólicos/química , Lignanas/química , Lignanas/isolamento & purificação , Estrutura Molecular , Nigéria , Ressonância Magnética Nuclear Biomolecular , Casca de Planta/química , Caules de Planta/química , Ioimbina/análogos & derivados , Ioimbina/químicaRESUMO
Mitragynine is an indole alkaloid isolated from the Thai medicinal plant Mitragyna speciosa. We previously reported the morphine-like action of mitragynine and its related compounds in the in vitro assays. In the present study, we investigated the opioid effects of 7-hydroxymitragynine, which is isolated as its novel constituent, on contraction of isolated ileum, binding of the specific ligands to opioid receptors and nociceptive stimuli in mice. In guinea-pig ileum, 7-hydroxymitragynine inhibited electrically induced contraction through the opioid receptors. Receptor-binding assays revealed that 7-hydroxymitragynine has a higher affinity for micro-opioid receptors relative to the other opioid receptors. Administration of 7-hydroxymitragynine (2.5-10 mg/kg, s.c.) induced dose-dependent antinociceptive effects in tail-flick and hot-plate tests in mice. Its effect was more potent than that of morphine in both tests. When orally administered, 7-hydroxymitragynine (5-10 mg/kg) showed potent antinociceptive activities in tail-flick and hot-plate tests. In contrast, only weak antinociception was observed in the case of oral administration of morphine at a dose of 20 mg/kg. It was found that 7-hydroxymitragynine is a novel opioid agonist that is structurally different from the other opioid agonists, and has potent analgesic activity when orally administered.
Assuntos
Analgésicos Opioides/farmacologia , Mitragyna , Dor/tratamento farmacológico , Extratos Vegetais/farmacologia , Alcaloides de Triptamina e Secologanina/farmacologia , Administração Oral , Analgésicos Opioides/administração & dosagem , Animais , Relação Dose-Resposta a Droga , Cobaias , Íleo/efeitos dos fármacos , Íleo/fisiologia , Injeções Subcutâneas , Masculino , Camundongos , Mitragyna/química , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Medição da Dor , Limiar da Dor/efeitos dos fármacos , Extratos Vegetais/química , Receptores Opioides mu/metabolismo , Alcaloides de Triptamina e Secologanina/administração & dosagem , Alcaloides de Triptamina e Secologanina/metabolismo , CaudaRESUMO
Previously, we reported that mesaconitine, an aconite alkaloid, increased intracellular Ca(2+) concentration ([Ca(2+)](i)) level in endothelium and caused relaxation in rat aorta via nitric oxide production. In the present study, we investigated the mechanisms of increase in the [Ca(2+)](i) level induced by mesaconitine in rat aorta and in human umbilical vein endothelial cells (HUVECs). Treatment with the low Na(+) buffer delayed the 30 microM mesaconitine-, but not 10 microM acetylcholine-, induced relaxation in rat aorta. Treatments with an inhibitor of Na(+)/Ca(2+) exchangers (20 microM 3',4'-dichlorobenzamil) and a reversed mode (Ca(2+) influx) inhibitor of the exchangers (30 microM 2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methanesulfonate, KBR7943) showed similar effects. In HUVECs, 30 microM mesaconitine increased the [Ca(2+)](i) level in the presence of extracellular CaCl(2) and NaCl, and the response was inhibited by KBR7943. Mesaconitine increased intracellular Na(+) concentration level in HUVECs. The [Ca(2+)](i) response by mesaconitine was inhibited by 100 microM D-tubocurarine (an inhibitor of nicotinic acetylcholine receptors), but was not inhibited in the glucose-free buffer and by inhibitors of Na(+)/H(+) exchangers. These findings suggest that mesaconitine stimulated Ca(2+) influx via the Na(+)/Ca(2+) exchangers in endothelial cells and caused relaxation in the aorta. The possibility of D-tubocurarine-sensitive Na(+) channels as target(s) of mesaconitine is discussed.
Assuntos
Aconitina/análogos & derivados , Aconitina/farmacologia , Aorta Torácica/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Trocador de Sódio e Cálcio/fisiologia , Vasodilatação/efeitos dos fármacos , Animais , Aorta Torácica/citologia , Aorta Torácica/fisiologia , Endotélio Vascular/citologia , Endotélio Vascular/fisiologia , Humanos , Masculino , Ratos , Ratos Wistar , Vasodilatação/fisiologiaRESUMO
Camptothecin derivatives are clinically used antitumor alkaloids that belong to monoterpenoid indole alkaloids. In this study, we investigated the biosynthetic pathway of camptothecin from [1-13C]glucose (Glc) by in silico and in vivo studies. The in silico study measured the incorporation of Glc into alkaloids using the Atomic Reconstruction of Metabolism software and predicted the labeling patterns of successive metabolites from [1-13C]Glc. The in vivo study followed incorporation of [1-13C]Glc into camptothecin with hairy roots of Ophiorrhiza pumila by 13C nuclear magnetic resonance spectroscopy. The 13C-labeling pattern of camptothecin isolated from the hairy roots clearly showed that the monoterpene-secologanin moiety was synthesized via the 2C-methyl-D-erythritol 4-phosphate pathway, not via the mevalonate pathway. This conclusion was supported by differential inhibition of camptothecin accumulation by the pathway-specific inhibitors (fosmidomycin and lovastatin). The quinoline moiety from tryptophan was also labeled as predicted by the Atomic Reconstruction of Metabolism program via the shikimate pathway. These results indicate that camptothecin is formed by the combination of the 2C-methyl-D-erythritol 4-phosphate pathway and the shikimate pathway. This study provides the innovative example for how a computer-aided comprehensive metabolic analysis will refine the experimental design to obtain more precise biological information.
Assuntos
Camptotecina/biossíntese , Glucose/metabolismo , Rubiaceae/metabolismo , Camptotecina/química , Isótopos de Carbono , Ciclo do Ácido Cítrico , Simulação por Computador , Glucose/química , Glicólise , Glucosídeos Iridoides , Iridoides/metabolismo , Modelos Biológicos , Ressonância Magnética Nuclear Biomolecular , Via de Pentose Fosfato , Raízes de Plantas/metabolismo , Triptofano/biossínteseRESUMO
Ten new alkaloids, lycoposerramines-F (1), -G (2), -H (3), -I (4), -J (5), -K (6), -L (7), -M (8), -N (9), and -O (10), having lycopodine-related structures, were isolated from the club moss Lycopodium serratum THUNB. and their structures were elucidated on the basis of spectroscopic analysis and/or chemical transformation.
Assuntos
Alcaloides/química , Alcaloides/isolamento & purificação , Lycopodium , Quinolizinas/química , Quinolizinas/isolamento & purificação , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Estruturas VegetaisRESUMO
Three new gelsedine-type oxindole alkaloids, GS-1, GS-2, and GS-3, and one new iridoid, GSIR-1, were isolated from the stems and leaves of cultivated Carolina jasmine (Gelsemium sempervirens AIT. f.) and their structures were determined by spectroscopic analysis.
Assuntos
Alcaloides/química , Alcaloides/isolamento & purificação , Gelsemium , Iridoides/química , Iridoides/isolamento & purificação , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Caules de PlantaRESUMO
[reaction: see text] Starting from (S)-glycidol, the asymmetric total synthesis of novel D-seco Corynanthe-type oxindoles Us-7 and Us-8 was accomplished. The structure of Us-7 was revised from the reported structure 1 with the (3R,7S) form to structure 22 with (3S,7R), and the absolute stereochemistry at C15 of both alkaloids was established.