RESUMO
Two lanostane triterpenoids (sclerodols A and B) were isolated from the culture of the Eucalyptus grandis derived from the endophyte Scleroderma UFSM Sc1(Persoon) Fries together with three known compounds: one related triterpenoid lanosta-8,23-dien-3ß,25-diol, the disaccharide α,ß-trehalose, and the sugar alcohol mannitol. Their structures were elucidated on the basis of 2D NMR, HRME, and single-crystal X-ray diffraction data. The methanol crude extract and the isolated lanostane triterpenoids showed promising anticandidal activities.
Assuntos
Antifúngicos/química , Basidiomycota/metabolismo , Triterpenos/química , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Cristalografia por Raios X , Eucalyptus/microbiologia , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Conformação Molecular , Triterpenos/isolamento & purificação , Triterpenos/farmacologiaRESUMO
The stereochemistry of discarines C (1) and D (2) and myrianthine A (3), three cyclopeptide alkaloids isolated from Discaria febrifuga, was determined by a combination of NMR studies of 1-3, enantioselective gas chromatography, and comparison of NMR data with those of synthetic tripeptides. For the synthesis of peptides, the nonproteinogenic amino acid 3-phenylserine was also obtained in its four diastereoisomeric forms (l and d threo, obtained by recrystallization of the diastereoisomeric tripeptide, and l and d erythro, obtained by a Mitsunobu reaction with the threo-tripeptides). The general synthetic strategy described in this paper allows the tripeptide to be obtained with the free N-terminal extremity protected or dimethylated. This strategy also allows the synthesis of the corresponding peptide with an imidazolidinone ring.
Assuntos
Alcaloides/isolamento & purificação , Peptídeos Cíclicos/isolamento & purificação , Rhamnaceae/química , Alcaloides/química , Brasil , Cromatografia Gasosa , Testes de Sensibilidade Microbiana , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Peptídeos Cíclicos/síntese química , Peptídeos Cíclicos/química , Casca de Planta/química , Raízes de Plantas/química , Serina/análogos & derivados , EstereoisomerismoRESUMO
A screening of the natural product chlorogenic acid, isolated from the Brazilian medicinal plant Hypericum brasiliense, caffeic acid, cinnamic acid, and p-methoxycinnamic acid, and derivatives of caffeoylquinic, caffeoyl, and cinnamoyl against the enzymes prolyl oligopeptidase and dipeptidyl peptidase IV was carried out. Caffeoylquinic, caffeoyl, and cinnamoyl derivatives were prepared using simple derivatization procedures and through coupling reactions with the amino acid proline. The dipeptidyl peptidase IV assay showed inhibitory activity of the tested compounds at a high concentration (500 µM) in the range of 81.5-7.2â%. In contrast, the derivatives methyl ester and 1,7-acetonide obtained from chlorogenic acid, and caffeic acid and its methyl ester derivative showed selectivity and activity as prolyl oligopeptidase inhibitors, with IC50 values of 3 to 14 mM.
Assuntos
Ácidos Cafeicos/química , Cinamatos/química , Dipeptidil Peptidase 4/química , Serina Endopeptidases/química , Inibidores de Serina Proteinase/química , Ácidos Cafeicos/isolamento & purificação , Cinamatos/isolamento & purificação , Dipeptidil Peptidase 4/isolamento & purificação , Espectrometria de Massas , Ressonância Magnética Nuclear Biomolecular , Rotação Ocular , Prolil OligopeptidasesRESUMO
Leonotis nepetifolia (L.) R. Br. (Lamiaceae) is a naturalised medicinal plant in Brazil known as 'cordão-de-frade', being used in folk medicine for the treatment of a variety of conditions such as infections and inflammations. L. nepetifolia leaf and flower essential oils were isolated by hydrodistillation, and their compounds were identified by GC-MS analysis. The leaf essential oil major constituents were germacrene D (31.5%), and ß-caryophyllene (19.2%), while in flower essential oil the main constituents were ß-elemene (31.2%), and germacrene D (12.1%). The essential oils were investigated against a broad spectrum of bacteria and fungi using the microdilution method, exhibiting MIC50 values of 3.93-250 µg mL-1. Both oils showed excellent antifungal properties, which is a very important finding since most fungi have shown increased resistance to known antifungal agents. According to these results, the essential oils of L. nepetifolia are promising sources of new antimicrobial agents, especially for yeast.
RESUMO
The absolute configuration of franganine (1), a cyclopeptide alkaloid isolated from the methanol root bark extract of Discaria americana, was established on the basis of detailed NMR spectroscopic data and X-ray diffraction analysis of its salt (2).
Assuntos
Alcaloides/química , Peptídeos Cíclicos/química , Brasil , Cristalografia por Raios X , Conformação Molecular , Estrutura Molecular , Casca de Planta/química , Rhamnaceae/química , SaisRESUMO
The phenylpropanoid glycoside verbascoside [2-(3,4-dihydroxyphenylethyl)-1-O-α-L-rhamnopyranosyl-(1â3)-ß-D-(4-O-caffeyl)-glucopyranoside] (1) has been isolated as the main constituent of the crude extract of Buddleja brasiliensis Jacq. ex Spreng from Southern Brazil. The crude extract, main fractions and the compound 1 were evaluated for inhibition of the enzymes acetylcholinesterase (AChE), dipeptidyl peptidase-IV (DPP-IV) and prolyl oligopeptidase (POP). Compound 1 showed weak activity against DPP-IV with an IC(50) >> 150 µM and was inactive against AChE, with a pMIQ determined by bioautography of 9.6. In contrast, 1 displayed significant inhibition of POP in a dose-dependent manner with an IC(50) value of 1.3 ± 0.2 µM, similar to the positive control, baicalin, with a POP IC(50) of 12 ± 3 µM.
Assuntos
Buddleja/química , Glucosídeos/química , Fenóis/química , Serina Endopeptidases/química , Inibidores de Serina Proteinase/química , Fracionamento Químico , Inibidores da Colinesterase/química , Inibidores da Colinesterase/isolamento & purificação , Inibidores da Dipeptidil Peptidase IV/química , Inibidores da Dipeptidil Peptidase IV/isolamento & purificação , Glucosídeos/isolamento & purificação , Concentração Inibidora 50 , Fenóis/isolamento & purificação , Extratos Vegetais/química , Prolil Oligopeptidases , Inibidores de Serina Proteinase/isolamento & purificaçãoRESUMO
A reinvestigation of the chemical constituents of the stem barks of Scutia buxifolia, a member of the Rhamnaceae, resulted, along with the known alkaloids scutianine C and scutianene L, in the isolation of three undescribed diastereoisomeric alkaloids - scutianine N, 27-epi-scutianine N and 3, 4, 7-tri-epi-scutianine N -, one undescribed non macrocyclic alkaloid - scutianine Q - and a neutral compound -scutianene M. Their structures were determined using extensive NMR techniques and HRMS. The absolute configurations of the stereogenic centers of the three diastereoisomeric alkaloids have been assigned by gas chromatography employing modified cyclodextrins as chiral stationary phases. Scutianine Q had its structure and stereochemistry defined by single crystal X-ray crystallographic analysis. All tested compounds showed good to moderate antibacterial activity (MICs between 1.56 and 100 µg mL-1) when evaluated in vitro against a panel of Gram-positive and Gram-negative bacteria. Some stereochemistry-activity relationships have been identified for the antibacterial activity of diastereoisomeric alkaloids against the Gram-negative bacteria Enterobacter aerogenes. The alkaloid 27-epi-scutianine N was as active as the standard antibiotic chloramphenicol (MIC = 1.56 µg mL-1), while scutianine N and 3,4,27-tris-epi-Scutianine N were inactive (>100 µg mL-1).
Assuntos
Alcaloides , Anti-Infecciosos , Rhamnaceae , Alcaloides/química , Antibacterianos/química , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Testes de Sensibilidade Microbiana , Extratos Vegetais , Rhamnaceae/químicaRESUMO
During the course of a study of Condalia buxifolia (Rhamnaceae), one new cyclopeptide alkaloid condaline B (1), together with six known cyclopeptide alkaloids, condaline A (2), and the scutianines B (3), - D (4) and -E (5), frangulanine (6), and 3,4,28-tris-epi-scutianene N (7), were isolated from the rind bark of Condalia buxifolia. Their structures have been confirmed through spectroscopic analyses such as 1D and 2D NMR experiments. The absolute stereochemistry of condaline A (2), was elucidated by X-ray crystal structure determination of its HI salt. In addition, condaline B (1) was obtained synthetically through a structural transformation of condaline A. Meanwhile, the crude methanol extract, the basic ether fraction, and alkaloids 1-7 were tested against various strains of Gram-positive and Gram-negative bacteria and fungus, showing promising antimicrobial activity.
Assuntos
Alcaloides , Rhamnaceae , Alcaloides/química , Antibacterianos , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Estrutura Molecular , Peptídeos Cíclicos/farmacologia , Casca de Planta/química , Rhamnaceae/químicaRESUMO
Phyllanthus tenellus Roxb. (Phyllanthaceae) is a plant used in Brazilian folk medicine for the treatment of intestinal infections and diabetes. Despite its use in traditional medicine, it was reported that P. tenellus extract may cause several effects in the central nervous system (CNS) of animals, such as agitation and signs of depression. The aim of this study was to determine the main constituents of P. tenellus methanol extract and to investigate whether the extract is able to inhibit the enzymes prolyl oligopeptidase (POP), acetylcholinesterase (AChE) and dipeptidyl peptidase-IV (DPP-IV). Corilagin (1) was isolated as the main constituent of the P. tenellus extract, along with rutin (2) and vitexin-2â³-O-rhamnoside (3). The extract presented the ability to inhibit mainly POP. Dichloromethane and ethyl acetate fractions showed the highest inhibitory potency against POP (IC50 values of 1.7 ± 0.4 and 11.7 ± 2 µg/mL, respectively). All fractions were inactive against AChE. Corilagin displayed selective POP inhibition in a dose-dependent manner, with IC50= 19.7 ± 2.6 µg/mL. Corilagin exhibited moderate capacity to pass through the phospholipid membrane by passive diffusion, presenting effective permeability (Pe) of 1.26 × 10-7 cm/s.
Assuntos
Acetilcolinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Phyllanthus/química , Prolil Oligopeptidases/antagonistas & inibidores , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Brasil , Inibidores da Colinesterase/química , Glucosídeos/farmacologia , Taninos Hidrolisáveis/farmacologia , Extratos Vegetais/farmacologia , Prolil Oligopeptidases/metabolismoRESUMO
This study investigated the antioxidant activity of Cuphea glutinosa (CG) and its effect on Na+, K+-ATPase from cardiac muscle. The ethanolic extract showed higher antioxidant capacity compared to aqueous and ethyl acetate fraction. Ethyl acetate fraction showed ß-sitosterol-3-O-ß-glucoside, kaempferol, quercetin, isoquercetin, gallic acid methyl ester, and gallic acid. The ethanolic extract also reduced the Na+,K+-ATPase activity. CG presented a promising antioxidant activity and inhibitory effect on the Na+, K+-ATPase activity, supporting biochemical evidences the popular use of this plant in the treatment of heart failure.
Assuntos
Antioxidantes/isolamento & purificação , Cuphea/química , Compostos Fitoquímicos/química , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Animais , Antioxidantes/química , Brasil , Coração/efeitos dos fármacos , Insuficiência Cardíaca/tratamento farmacológico , Quempferóis/isolamento & purificação , Miocárdio , Extratos Vegetais/química , Quercetina/isolamento & purificaçãoRESUMO
A phytochemical investigation of the stems of Waltheria douradinha resulted in isolation of two 4-quinolone alkaloids, waltherione B and vanessine, along with three known alkaloids, waltherione A, antidesmone and O-methyltembamide. Their structures were elucidated on the basis of their 2D NMR spectroscopic analyses, and from X-ray crystallographic analysis of waltherione A and the O-methyl derivative of waltherione B. Additionally, waltherione B and vanessine, and the O- and N-methyl derivatives of waltherione A and waltherione B, were evaluated for their antimicrobial activities; only vanessine displayed any (weak) antimicrobial activity.
Assuntos
Alcaloides/química , Malvaceae/química , Extratos Vegetais/química , Quinolonas/química , Alcaloides/farmacologia , Compostos Aza/química , Compostos Aza/farmacologia , Bactérias/efeitos dos fármacos , Cristalografia por Raios X , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Estrutura Molecular , Extratos Vegetais/farmacologia , Quinolinas/química , Quinolinas/farmacologia , Quinolonas/farmacologia , EstereoisomerismoRESUMO
The investigation of the crude extract of leaves and bark of Pilocarpus pennatifolius Lemaire allowed isolated of a not yet described coumarin, together with three known coumarins (bergapten, xanthotoxin and dimethyl allyl xanthyletin), and a not yet described imidazole alkaloid. All structures were established by means of spectral analysis, including extensive 2D NMR studies. In addition, the alkaloid had its absolute stereochemistry determined by X-ray diffraction. Meanwhile, extracts and pure compounds were tested against various strains of bacteria and fungi, showing promising antimicrobial activities. We highlight the activities of crude bark methanol extract (CBME), of the leaf basic acetate fraction (LBAcF), and of compound 2 against the Gram negative bacteria Shigella flexneri (MICsâ¯=â¯7.8, 7.8 and 3.12⯵g·mL-1, respectively), of compound 5 against the Gram positive Enterococcus fecalis (MICâ¯=â¯1.56⯵g·mL-1), and against two Gram negative bacteria Salmonella enteritidis (MICâ¯=â¯1.56⯵g·mL-1), and Pseudomonas aeruginosa (MICâ¯=â¯6.25⯵g·ml-1). On the other hand, CBME and compounds 3-5 showed excellent activity against the fungus Candida krusei with MICs of 15.6, 1.56, and 3.12⯵g·mL-1 respectively, as actives or better than the antifungal standard fluconazole (MICâ¯=â¯3.12⯵g·mL-1).
Assuntos
Anti-Infecciosos/isolamento & purificação , Compostos Fitoquímicos/isolamento & purificação , Pilocarpus/química , Extratos Vegetais/química , Anti-Infecciosos/farmacologia , Brasil , Cumarínicos/isolamento & purificação , Cumarínicos/farmacologia , Estrutura Molecular , Compostos Fitoquímicos/farmacologia , Casca de Planta/química , Folhas de Planta/químicaRESUMO
Two new iridoids (1-2) and a new decomposition product of valepotriates (3), together with fifteen known compounds (4-18) were isolated from the roots and rhizomes of Valeriana polystachya Smith, a native species from the Pampa Biome. Their structures were elucidated by means of NMR spectroscopy, mass spectrometry and optical rotation. The structures of 3 and 18 were further confirmed by single crystal X-ray diffraction analysis. In the group of the isolated compounds, 6ß-hydroxysitostenone, hydroxymaltol and isovillosol were isolated from the Valeriana genus for the first time. The extracts and isolated compounds were evaluated for their in vitro activities against acetylcholinesterase (AChE) and prolyloligopeptidase (POP). Compounds 7, 9 and 11 showed weak inhibitory activity against AChE, while 3 and 5 displayed exceptional POP inhibitory activity, with IC50 values of 5.3⯱â¯0.07 and 7.9⯱â¯0.4⯵M, respectively.
Assuntos
Inibidores da Colinesterase/isolamento & purificação , Iridoides/isolamento & purificação , Inibidores de Serina Proteinase/isolamento & purificação , Valeriana/química , Acetilcolinesterase , Brasil , Inibidores da Colinesterase/farmacologia , Iridoides/farmacologia , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Raízes de Plantas/química , Prolil Oligopeptidases , Rizoma/química , Serina Endopeptidases , Inibidores de Serina Proteinase/farmacologiaRESUMO
BACKGROUND: Several species of the genus Erythrina have been used as sedative, antidepressant, and anticonvulsant. Erythrina crista-galli is native to the Pampa Biome and is widely used for medicinal purposes. Erythrinan alkaloids exhibit a range of pharmacological properties. OBJECTIVE: The aim of this study was to evaluate the basic fractions and the alkaloids isolated from E. crista-galli bark against a collection of bacteria and fungi for the first time. METHODS: Erythrina crista-galli stem bark was extracted with MeOH under reflux. The crude extract was dissolved in water, acidified and extracted with diethyl ether. Basification of the aqueous solution followed by diethyl ether and ethyl acetate extractions gave the basic ether and basic ethyl acetate fractions. Chromatographic purification of these fractions afforded five known alkaloids: erytharbine (1), erysotrine (2), erysotramidine (3), erysotrine N-oxide (4) and erythratidine (5) along with a new alkaloid named here erythratidine N-oxide (6). Alkaloids 1-6 were investigated against a collection of bacteria and fungi using the broth micro dilution method. RESULTS: In this work, a new alkaloid was isolated from E. crista-galli. The most significant bacterial inhibitory effect of alkaloidal fractions was observed against the Gram-negative Pseudomas aeroginosa (MIC values of 31.25 µg.mL-1). Basic ether fraction displayed good antimicrobial activity against Shigella sonnei with MIC= 62.5 µg.mL-1. Isolated alkaloids 1-6 showed inhibitory activity against all bacteria tested (MIC values of 50-100 µg.mL-1). In addition, the crude extract and alkaloids 1, 2, and 5 also showed good antifungal potential against Candida krusei (MICs between 12.5 and 31.25 µg.mL-1). The previously undescribed alkaloid 6 presented MIC values between 50 and 100 µg.mL-1 against all tested microorganisms. CONCLUSION: In general, as with a considerable number of phytochemicals with antimicrobial activity, alkaloids 1-6 may be considered with potential as antibacterial/antifungal agents. The MIC values of the extract, alkaloidal fractions and compounds 1-6 indicate that, at least in part, the isolates were responsible for the antimicrobial activity observed.
Assuntos
Alcaloides/farmacologia , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Erythrina/química , Alcaloides/química , Alcaloides/isolamento & purificação , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antifúngicos/química , Antifúngicos/isolamento & purificação , Bactérias/efeitos dos fármacos , Fungos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Casca de Planta/químicaRESUMO
Chemical investigation of the aerial parts of Leonurus sibiricus L. used in Brazilian folk medicine led to the identification of the following constituents: the labdane-type diterpenoid leojaponin, the phytosterols ß-sitosterol and ß-sitosterol glucoside and the alkaloid leonurine. The crude extracts obtained from methanol and methanol/1% HCl and pure compounds isolated from L. sibirius were investigated as acetylcholinesterase (AChE) and prolyl oligopeptidase (POP) inhibitors. Extracts obtained by maceration were active against POP (53-58%), but showed weak activity against AChE. The isolated leojaponin and leonurine were evaluated as POP inhibitors.
Assuntos
Acetilcolinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Leonurus/química , Extratos Vegetais/farmacologia , Serina Endopeptidases/metabolismo , Inibidores de Serina Proteinase/farmacologia , Diterpenos/farmacologia , Ácido Gálico/análogos & derivados , Ácido Gálico/farmacologia , Prolil OligopeptidasesRESUMO
Extraction and characterization of natural products from the bark of the trunk of Helietta apiculata Benth (Rutaceae) afforded nine alkaloids, eight furoquinoline and one quinolone, limonine, three cinnamic acid derivatives, three neolignans, tetracosanoic acid, six coumarins, of which apiculin A and apiculin B (neolignans), and tanizin (coumarin) are previously undescribed compounds. The structures of all compounds were determined by spectroscopic methods, and the crystal structures of two of the newly undescribed compounds, apiculin A and apiculin B, were determined by X-ray analysis. Extracts and pure compounds isolated from Helietta apiculata showed promising antimicrobial activities.
Assuntos
Cumarínicos/química , Lignanas/química , Casca de Planta/química , Rutaceae/química , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antifúngicos/química , Antifúngicos/isolamento & purificação , Cumarínicos/isolamento & purificação , Lignanas/isolamento & purificação , Estrutura Molecular , Compostos Fitoquímicos/química , Compostos Fitoquímicos/isolamento & purificação , Extratos Vegetais/químicaRESUMO
BACKGROUND: The genus Hypericum (family Clusiaceae) comprises various species that are used in traditional medicine, such as wound healing, antidepressant, and anticancer agents. OBJECTIVE: The aim of this study was to evaluate the inhibitory capacity of extracts and fractions from two Hypericum species used in the Brazilian folk medicine (H. brasiliense and H. connatum) against the enzymes prolyl oligopeptidase (POP), dipeptidyl peptidase-IV (DPP-IV), and acetylcholinesterase (AChE), as well as to identify their main active constituents. METHODS: Dried aerial parts of H. connatum and H. brasiliense were subjected to extraction with 8:2 methanol-H2O. Each hydroalcoholic extract was fractioned resulting in ethyl acetate and aqueous fractions. The activity of POP, DPP-IV and AChE was determined in vitro in 96-well microplates. RESULTS: The main components identified in the plant extracts were chlorogenic acid (1), quercitrin (2), rutin (3), quercetin (4), and isoquercitrin (5). Hydroalcoholic extracts, ethyl acetate and aqueous fractions showed high POP inhibitory activity with IC50 values of 2.6 to 3.7 µg/mL. AChE and DPP-IV inhibitory effects were very low for all extracts and substances. CONCLUSION: Chlorogenic acid (1) and quercetin (4) were the main constituent responsible for the activity observed against POP. Parallel artificial membrane permeability assay of ethyl acetate fractions of both species showed that the metabolite that can effectively pass through the lipid membrane is 4, the aglycone form of 2, 3 and 5.
Assuntos
Acetilcolinesterase/química , Inibidores da Colinesterase/química , Extratos Vegetais/química , Serina Endopeptidases/química , Inibidores de Serina Proteinase/química , Ácido Clorogênico/química , Ácido Clorogênico/isolamento & purificação , Inibidores da Colinesterase/isolamento & purificação , Difusão , Dipeptidil Peptidase 4/química , Inibidores da Dipeptidil Peptidase IV/química , Inibidores da Dipeptidil Peptidase IV/isolamento & purificação , Ensaios Enzimáticos , Hypericum , Membranas Artificiais , Permeabilidade , Fosfolipídeos/química , Extratos Vegetais/isolamento & purificação , Prolil Oligopeptidases , Quercetina/química , Quercetina/isolamento & purificação , Inibidores de Serina Proteinase/isolamento & purificaçãoRESUMO
The present study reports a cyclopeptide alkaloid, scutianine M, isolated from the methanolic root bark extract of Scutia buxifolia Reiss (Rhamnaceae) along with six known compounds, scutianines-B, -C, -D, -E, -F, and scutianene D. Its structure was established on the basis of spectroscopic analyses, including application of 2D NMR spectroscopic techniques. As part of a study of the bioactive compounds of medicinal plants from southern Brazil, we also compared the antimicrobial activity of the isolated compounds towards Gram (+), Gram (-) bacteria, and yeasts.
Assuntos
Alcaloides/isolamento & purificação , Alcaloides/farmacologia , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Peptídeos Cíclicos/isolamento & purificação , Peptídeos Cíclicos/farmacologia , Rhamnaceae/química , Alcaloides/química , Antibacterianos/química , Bactérias/efeitos dos fármacos , Estrutura Molecular , Peptídeos Cíclicos/química , Casca de Planta/química , Raízes de Plantas/químicaRESUMO
The chemical investigation of the methanolic extract of the root bark of Waltheria douradinha (Sterculiaceae) afforded an unusual quinolinone alkaloid named waltherione-A (1). Its structure was determined mainly by NMR spectroscopic methods. The antibacterial activity of waltherione-A (1) and the corresponding O-methylated derivative (2) was tested against three gram-negative and three gram-positive bacteria, with only (2) having moderate activity.
Assuntos
Malvaceae/química , Quinolinas/química , Antibacterianos/química , Antibacterianos/farmacologia , Estrutura Molecular , Casca de Planta/química , Raízes de Plantas/química , Quinolinas/farmacologiaRESUMO
The isolation and structure determination of cyclic peptide alkaloids, discarine-M and discarine-N, along with seven known cyclic peptide alkaloids, adouetine-Y', franganine, frangulanine, discarines-A, -B, -C, and -D from the root bark of Discaria americana are described. Structures were determined spectroscopically, especially using 2D NMR spectroscopic analysis. The crude methanol extract, the basic ether extract, and the alkaloids 6 and 7 also weakly inhibited growth of gram-negative and gram-positive bacteria.