RESUMO
Cytotoxicity-guided fractionation of the bark and stem extract of Polylepis racemosa led to the identification of ursolic acid, pomolic acid, 3-O-acetylpomolic acid, and 2-oxopomolic acid. Pomolic acid was the most cytotoxic component, and was specific for M-14 melanoma and ME180 cervical carcinoma, with GI50 values of 6.9 and 8.3 micrograms/mL respectively.
Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Plantas Medicinais/química , Triterpenos/isolamento & purificação , Animais , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Cromatografia Líquida de Alta Pressão , Humanos , Espectroscopia de Ressonância Magnética , Camundongos , Ácido Oleanólico/análogos & derivados , Ácido Oleanólico/química , Ácido Oleanólico/isolamento & purificação , Ácido Oleanólico/farmacologia , Peru , Caules de Planta/química , Triterpenos/química , Triterpenos/farmacologia , Células Tumorais Cultivadas , Ácido UrsólicoRESUMO
Continuation of a previous study on Renealmia alpinia resulted in the isolation of the new labdane diterpenoid 3, together with two known diterpenoids. The structure of the new diterpenoid was determined by a combination of NMR techniques and HRFABMS.
Assuntos
Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Diterpenos/isolamento & purificação , Zingiberales/química , Diterpenos/farmacologia , Espectroscopia de Ressonância Magnética , Saccharomyces cerevisiae/efeitos dos fármacos , Espectrometria de Massas de Bombardeamento Rápido de Átomos , SurinameRESUMO
Continuation of a previous study on Renealmia alpinia resulted in the isolation of the new labdane diterpenoid 3, together with two known diterpenoids. The structure of the new diterpenoid was determined by a combination of NMR techniques and HRFABMS. (AU)
Assuntos
Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Diterpenos/isolamento & purificação , Zingiberales/química , Diterpenos/farmacologia , Espectroscopia de Ressonância Magnética , Saccharomyces cerevisiae/efeitos dos fármacos , Espectrometria de Massas de Bombardeamento Rápido de Átomos , SurinameRESUMO
Bioassay-guided fractionation of Eschweilera coriacea collected in the lowland wet forest of Suriname yielded the new but only weakly active ellagic acid derivative eschweilenol A (1) and the two new but inactive ellagic acid derivatives eschweilenol B (2) and eschweilenol C (3). The four known compounds, sucrose, ellagic acid, 3-O-galloylepigallocatechin, and epigallocatechin, were also isolated. The structures of the three new compounds were determined by spectrometric methods, primarily from the HMQC, HMBC, NOESY, and ROESY NMR techniques, and chemical methods, including methylation and triethylsilylation. The location of a hydroxyl group in one ellagic acid derivative was determined by a new technique involving an NOE correlation of the protons of a triethylsilyl derivative with a proton on a neighboring aromatic ring.
Assuntos
Ácido Elágico/análogos & derivados , Epiderme Vegetal/química , Plantas Medicinais/química , Antifúngicos/farmacologia , Sequência de Carboidratos , Cromatografia em Camada Fina , Ácido Elágico/isolamento & purificação , Ácido Elágico/farmacologia , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Espectrofotometria Ultravioleta , Suriname , Leveduras/efeitos dos fármacosRESUMO
The preservation of tropical rainforests is an important goal both for the intrinsic value of their cultural and biological diversity as well as for the well-being of the peoples who make these forests their home. In addition, tropical forests are potential sources of new pharmaceutical products that can only be found by chemical prospecting in Nature's genetically encoded combinatorial library. As part of an effort to integrate biodiversity conservation and drug discovery with economic development, we have initiated a collaborative program to discover potential pharmaceuticals in the rainforest of Suriname. The plant Renealmia alpinia (Zingiberaceae) was selected for investigation based on its ethnomedical use as a febrifuge, but testing in the yeast Sc-7 assay gave a positive response, indicative of cytotoxic activity. Using this bioassay, the two new labdane diterpense, 11-hydroxy-8(17),12(E)-labdadien-15,-16-dial 11,15-hemiacetal (1) and 16-oxo-8(17),12(E)-labdadien-15-oic acid (2), and the known diterpene, 8(17),12(E)-labdadien-15,16-dial (3), have been isolated. Their structures were elucidated by 1D and 2D NMR techniques (DEPT, COSY, HETCOR, HMBC, and NOESY) and IR, UV, and MS spectra, and the absolute stereochemistry of 1 was established by CD spectroscopy and by the formation and NMR analysis of alpha-methoxyphenylacetyl esters. The hemiacetal 1 was cytotoxic to M109 cells, with an IC50 value of 2.6 micrograms/mL.
Assuntos
Diterpenos/isolamento & purificação , Plantas Medicinais/química , Animais , Diterpenos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Camundongos , Extratos Vegetais/química , Saccharomyces cerevisiae/efeitos dos fármacos , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta , Suriname , Células Tumorais CultivadasRESUMO
(1) Pseudolaric acids--Novel diterpenes, Pseudolaric acid A, B, C and D were isolated from Pseudolarix kaempferi Gorden (pinaceae). Their structures were assigned by spectroscopic data and chemical correlations. In the continuous studies, the absolute configurations, the conformations in the solutions, the fragmentation mechanisms of MS and assignments of all NMR spectral signals were also reported. They showed the antifungal and cytotoxic activities. (2)--Daphnane diterpenes--In the further studies on the plants of Thymelaeaceae, besides 10 known diterpenes, 16 new daphnane diterpenes were isolated from Daphne genkwa, D. tangutica, D. giraldii, Wikstroemie chamaedaphne. They showed the antifertilities activities. (3) Tripterygium diterpenes--14 new diterpenes were isolated from Triperygium wilfordii, T. regeli and T. hypoglaucum. Some of them showed the antitumour activities. The CD spectra showed that A/B ring of all compounds have trans configuration as same as tripdiolide and triptolide determined by X-ray diffraction. (4) Pregnane glycosides from Marsdenia koi--Two new pregnane glycosides marsdenikoiside A and marddenikoiside B which can terminate the early pregnancy were isolated from Marsdeia koi. Their structures were elucidated by hydrolysis and spectroscopic methods.
PIP: Bioactive terpenes were isolated from the following plant species: 1) Pseudolaric acids: The active compounds of novel diterpenes, Pseudolaric acid A, B, C, and D, were isolated from Pseudolarix kaempferi Gordon (pinaceae). Their structures were determined by spectroscopic data and chemical correlations. In continuous studies, absolute configurations, confirmation in solutions, fragmentation mechanisms of MS, and assignments of all nuclear magnetic resonance (NMR) spectral signals were also reported. They showed antifungal and cytotoxic activities. Pseudolaric acid A 1 and B 2 showed antifungal activities. Recently, pseudolaric acid B was established as a general cytotoxic agent against P-388 lymphocytic leukemia, KB carcinoma of the nasopharynx, HT-1080 fibrosarcoma, H00 578T breast cancer, human melanoma, human lung cancer, and human colon cancer cell lines. 2) Daphnane diterpenes: In further studies on the plants of Thymelaeaceae, besides 10 known diterpenes, 16 new daphnane diterpenes were isolated from Daphne genkwa, D. tangutica, D. giraldii, Wikstroemie chamaedaphne that showed antifertility activities. In continuous studies, besides 6 known compounds, 17 new daphnane diterpenes were isolated. 3) Tripterygium diterpenes: 14 new diterpenes were isolated from Tripterygium wilfordii, T. regeli and T. hypoglaucum. Tripterygium wilfordii has been used as an anticancer drug, male contraceptive, and immunedepressant in Chinese folk medicine for a long time. Some of them showed antitumor activities. The CD spectra showed that A/B ring of all diterpenes had the same transconfiguration as tripdiolide and triptolide as determined by X-ray diffraction. In 1972 triptolide, tripdiolide and triptonide were isolated with significant anti-tumor activities. Celastrol demonstrated immunodepressive activities. In addition to 10 known triterpenes, 15 new diterpenes were isolated from the plants of Tripterygium by silica gel chromatography. 4) Pregnane glycosides from Marsdenia koi: Two new pregnane glycosides, marsdenikoiside A and marsdenikoiside B, which can terminate early pregnancy were isolated from Marsdenia koi. Their structures were elucidated by hydrolysis and spectroscopic methods.