RESUMO
Purification of a diethyl ether extract of the Argentinian fern Elaphoglossum lindbergii afforded five new prenylated acylphloroglucinols, lindbergins E-I (1-5), of which two showed significant in vitro leishmanicidal activity against promastigotes of Leishmania braziliensis and L. amazonensis. The structures of compounds 1-5 were elucidated based on analysis of their spectroscopic data and comparison with values previously reported for other phloroglucinol derivatives isolated from plant species of the genera Hypericum, Dryopteris, and Elaphoglossum. Fragmentation and rearrangement patterns of prenylated acylphloroglucinols were analyzed, and some mechanisms were proposed to rationalize the peaks observed in the mass spectra of these natural products produced by EI and FAB. Compounds isolated from E. lindbergii show the opposite absolute configuration when compared to those reported from E. crassipes. Empirical evidence indicates that acylphloroglucinols carrying a prenylated acylfilicinic acid residue possess a high-amplitude configuration-dependent Cotton effect centered at 350-360 nm in their CD curves, from which the absolute configuration of the sole chiral center of the prenylated acylfilicinic acid moiety can be deduced.
Assuntos
Gleiquênias/química , Leishmania/efeitos dos fármacos , Floroglucinol/isolamento & purificação , Floroglucinol/farmacologia , Hypericum/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Floroglucinol/química , PrenilaçãoRESUMO
A short total synthesis of (±)-garcinol and (±)-isogarcinol, two endo-typeâ B PPAPs with reported activity against methiciline resistant Staphylococcus aureus (MRSA), is presented. The separation of framework-constructing from framework-decorating steps and the application of two highly regio- and stereoselective Pd-catalysed allylations, that is, the Pd-catalysed decarboxylative Tsuji-Trost allylation and the diastereoselective Pd-catalysed allyl-allyl cross-coupling, are key elements that allowed the total synthesis to be accomplished within 13 steps starting from acetylacetone. After separation of the enantiomers the absolute configurations of the four natural products (i.e., (-)-garcinol, (+)-guttiferoneâ E (i.e., ent-garcinol), (-)-isogarcinol, and (+)-isoxanthochymol (i.e., ent-isogarcinol)) were assigned based on ECD spectroscopy.
RESUMO
Nine new terpenylated acylphloroglucinols, crassipins A-I, were isolated from the rhizomes and roots of the fern Elaphoglossum crassipes, and their structures were elucidated by analysis of spectroscopic data and chemical derivatization. The absolute configurations of some of the compounds were established by CD and VCD in combination with a quantum mechanical method. Crassipin A (1), the major acylphloroglucinol of the Et(2)O extract of E. crassipes, as well as its peracetylated derivative (8), displayed antidepressant-like activity in a mouse forced-swimming test when administered orally at a dose of 15 mg/kg.
Assuntos
Antidepressivos , Dryopteridaceae/química , Floroglucinol , Administração Oral , Animais , Antidepressivos/química , Antidepressivos/isolamento & purificação , Antidepressivos/farmacologia , Argentina , Relação Dose-Resposta a Droga , Camundongos , Estrutura Molecular , Atividade Motora/efeitos dos fármacos , Floroglucinol/análogos & derivados , Floroglucinol/química , Floroglucinol/isolamento & purificação , Floroglucinol/farmacologia , Raízes de Plantas/química , Rizoma/química , NataçãoRESUMO
Four unusual terpenylated acylphloroglucinols were isolated from the diethyl ether extract of the scales and rhizomes of the fern Dryopteris wallichiana together with the known compounds albaspidins AA and AB, and filixic acids ABA and ABB. Structures of the isolated compounds were established by extensive spectroscopic analysis and their absolute configuration at C-14â³ was determined by comparing their CD spectra with those simulated for the respective isomers. Pure acylphloroglucinols displayed moderate in vitro nematocidal activity against L4 stage larvae of Nippostrongylus brasiliensis (LD50=22-121 µM).
Assuntos
Antinematódeos/química , Antinematódeos/farmacologia , Dryopteris/química , Terpenos/química , Terpenos/farmacologia , Animais , Antinematódeos/isolamento & purificação , Estágios do Ciclo de Vida/efeitos dos fármacos , Nippostrongylus/efeitos dos fármacos , Nippostrongylus/crescimento & desenvolvimento , Terpenos/isolamento & purificaçãoRESUMO
The molluscicidal activity of 12 phloroglucinol derivatives previously isolated from Elaphoglossum piloselloides, E. gayanum, E. yungense, and E. lindbergii, as well as 3 known acylphloroglucinols, now reported from an Argentine collection of Dryopteris wallichiana, was evaluated against the schistosomiasis vector snail Biomphalaria peregrina. Molluscicidal effects were analyzed and compared with those previously observed for 4 acylphloroglucinols from E. piloselloides and their corresponding peracetylated derivatives, in order to draw structure-activity relationships. The most active compounds were the prenylated desaspidins elaphogayanin B and elaphopilosins A and B (LD50 = 1.90, 2.90, and 0.94 ppm, respectively), together with the only evaluated prenylated para-aspidin, elaphopilosin C (LD50 = 2.15 ppm). Quantitative structure-activity relationships (QSAR) were studied by means of a semiempirical method (PM3) for the 24 natural phloroglucinol derivatives included in this paper. The descriptor molecular volume was found to have good correlation with the observed molluscicidal activity (r2 = 0.77). The derived equation can be considered useful to predict the molluscicidal activity of bi and tricyclic acylphloroglucinols. The QSAR analysis showed that there is an optimum volume for high activity, probably related to the size of a receptor's active site. Bigger molecules display lower activity.
Assuntos
Gleiquênias/química , Moluscocidas , Floroglucinol/análogos & derivados , Floroglucinol/toxicidade , Animais , Argentina , Produtos Biológicos , Cromatografia em Gel , Cromatografia em Camada Fina , Dose Letal Mediana , Espectroscopia de Ressonância Magnética , Floroglucinol/química , Relação Quantitativa Estrutura-Atividade , Rizoma/química , Caramujos , Relação Estrutura-AtividadeRESUMO
Seven new prenylated acylphloroglucinols, yungensins A-G, were isolated from the diethyl ether extract of the scaly rhizomes and roots of an Argentine collection of the fern Elaphoglossum yungense. All the compounds contained a geranyl group attached to the filicinic acid-type residue. The diethyl ether extract and yungensins A-F displayed antibacterial effects against Staphylococcus aureus and Pseudomonas aeruginosa with MICs ranging from 10 to 200 µg/mL. All tested acylphloroglucinols, except for yungensin D, caused bacteriolysis of S. aureus at MBC or higher doses (50-200 µg/mL). At 10 µg/mL, the ether extract as well as yungensins A, B, and D-F altered the biofilm production in both microoganisms.
Assuntos
Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Gleiquênias/química , Floroglucinol/análogos & derivados , Floroglucinol/isolamento & purificação , Floroglucinol/farmacologia , Antibacterianos/química , Argentina , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Floroglucinol/química , Prenilação , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Streptococcus pneumoniae/efeitos dos fármacosRESUMO
Five new prenylated phloroglucinols were isolated from the diethyl ether extracts of the ferns Elaphoglossum gayanum and E. piloselloides. Their structures were established by analysis of their spectroscopic data (1D and 2D NMR, HRMS, and IR) and chemical derivatization. The two major compounds exhibited moderate molluscicidal activity against the snail Biomphalaria peregrina, a vector of the tropical disease schistosomiasis, with LD(50) 7.2 microg/mL (14.4 microM) and 11.7 microg/mL (22.2 microM).
Assuntos
Gleiquênias/química , Moluscocidas/isolamento & purificação , Floroglucinol/análogos & derivados , Floroglucinol/isolamento & purificação , Caramujos/efeitos dos fármacos , Animais , Argentina , Estrutura Molecular , Moluscocidas/química , Moluscocidas/farmacologia , Ressonância Magnética Nuclear Biomolecular , Floroglucinol/química , Floroglucinol/farmacologia , Esquistossomose/tratamento farmacológicoRESUMO
Two new bicyclic phloroglucinols were isolated from the diethyl ether extract of an Argentine collection of the fern Elaphoglossum piloselloides. Structures were established by analysis of their spectroscopic data ((1)H NMR, HRMS, IR) and chemical derivatization. Both compounds show an acute molluscicidal activity against the schistosomiasis vector snail Biomphalaria peregrina.
Assuntos
Biomphalaria/efeitos dos fármacos , Gleiquênias/química , Moluscocidas/isolamento & purificação , Moluscocidas/farmacologia , Floroglucinol/análogos & derivados , Floroglucinol/isolamento & purificação , Floroglucinol/farmacologia , Animais , Argentina , Vetores de Doenças , Estrutura Molecular , Moluscocidas/química , Floroglucinol/química , Esquistossomose/etiologiaRESUMO
Elaphoside-A [p-vinylphenyl (beta-D: -glucopyranosyl)-(1-->3)-beta-D: -allopyranoside], a Mediterranean fruit fly oviposition deterrent, was previously isolated from an Argentine collection of the fern Elaphoglossum piloselloides. In order to establish the structural requirements for the observed oviposition inhibition, we synthesized and characterized 4 known and 21 new aromatic glycosides structurally related to elaphoside-A. Their effects on the oviposition behavior of Ceratitis capitata females are discussed.
Assuntos
Ceratitis capitata/efeitos dos fármacos , Glicosídeos/farmacologia , Oviposição/efeitos dos fármacos , Animais , Ceratitis capitata/anatomia & histologia , Cromatografia Líquida de Alta Pressão , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Espectrofotometria InfravermelhoRESUMO
Fifteen new diterpenoid glycosides (1a-n, 2) were isolated from an Argentine collection of the bitter fern Gleichenia quadripartita along with the known flavonoid glycoside afzelin. Structure elucidation was accomplished by 1D and 2D NMR spectroscopy and by high-resolution MS analyses. In addition, X-ray crystallographic analysis of a monocrystal of 1a as well as chemical derivatization of 1h and 1m were performed to confirm their structures.
Assuntos
Diterpenos/química , Diterpenos/isolamento & purificação , Gleiquênias/química , Glicosídeos/química , Glicosídeos/isolamento & purificação , Argentina , Cristalografia por Raios X , Manosídeos/química , Manosídeos/isolamento & purificação , Conformação Molecular , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Proantocianidinas/química , Proantocianidinas/isolamento & purificaçãoRESUMO
The drimane-type sesquiterpenoids (-)-polygodial (1), (-)-isopolygodial (4), drimenin (5), and isodrimenin (6) were isolated from a pungent Argentine collection of the fern Thelypteris hispidula, along with other terpenoids. As the mentioned drimanes have been previously found in liverworts, the present results strongly support the theory that Pteridophytes and Bryophytes share the same line of evolution. Our present investigations indicate that two chemotypes of T. hispidula are widespread in the northwest of Argentina. Plants belonging to the pungent chemotype contain drimanes, while nonpungent plants lack drimanes.