RESUMO
A new phenylpropanoid glycoside, dolichandroside-A, together with seven known compounds alpha-lapachone, lapachol, aloesaponarin II, 8-hydroxydehydroiso-alpha-lapachone, beta-sitosterol, 3,8-dihydroxydehydroiso-alpha-lapachone and verbascoside were isolated from the active ethyl acetate soluble extract of heartwood of Dolichandrone falcata. All except for dolichandroside-A are known compounds, but have been isolated for the first time from this plant. The structure of all these compounds was determined on the basis of 1D- and 2D-NMR spectral data. All the isolates were tested for alpha-glucosidase inhibitory and DPPH radical scavenging activity. This is the first report identifying DPPH scavenging activity and alpha-glucosidase inhibitory activity in D. falcata. Furthermore, along with a new compound, dolichandroside-A, this study also assigns for the first time alpha-glucosidase inhibitory activity to verbascoside and aloe saponarin-II.
Assuntos
Bignoniaceae/química , Inibidores Enzimáticos/farmacologia , Sequestradores de Radicais Livres/farmacologia , Inibidores de Glicosídeo Hidrolases , Glicosídeos/farmacologia , Extratos Vegetais/farmacologia , Antraquinonas/farmacologia , Compostos de Bifenilo/metabolismo , Inibidores Enzimáticos/isolamento & purificação , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/isolamento & purificação , Glucosídeos/farmacologia , Glicosídeos/isolamento & purificação , Estrutura Molecular , Fenóis/farmacologia , Picratos/metabolismo , Extratos Vegetais/químicaRESUMO
The hexane and chloroform extracts of Derris scandens have displayed potent alpha-glucosidase inhibitory and moderate free radical scavenging activities. Phytochemical investigation of the active extracts led to the isolation of three new prenylated isoflavones, isoscandinone, scandenin A and scandenin B in addition to scandenone, scandinone and 4', 5', 7-trihydroxybiprenylisoflavone as the main constituents, having alpha-glucosidase enzyme inhibitory and free radical scavenging properties. A reversed-phase HPLC method is developed to quantify these active principles in the plant material, which can serve as an effective quality control method for standardization of D. scandens.
Assuntos
Derris/química , Inibidores Enzimáticos/química , Sequestradores de Radicais Livres/química , Glicosídeo Hidrolases/antagonistas & inibidores , Isoflavonas/química , Isoflavonas/farmacologia , Animais , Cromatografia Líquida de Alta Pressão , Inibidores Enzimáticos/isolamento & purificação , Inibidores Enzimáticos/farmacologia , Sequestradores de Radicais Livres/isolamento & purificação , Sequestradores de Radicais Livres/farmacologia , Concentração Inibidora 50 , Isoflavonas/isolamento & purificação , Extratos Vegetais/química , Caules de Planta/química , RatosRESUMO
Two new furanoflavonoids (1, 2), one new chalcone dimer (3) along with six known compounds, chrysophanol, 5-O-methyl squarrosin, 5-methoxy furano[4'',5'',6,7]flavone, calodenone, lophirone A and lophirone H were isolated from the ethyl acetate-soluble fraction of methanol extract of root bark of Ochna squarrosa. Chrysophanol, calodenone, lophirone A and lophirone H were isolated from this plant for the first time. The structures of all the isolated compounds were confirmed by 1D and 2D spectroscopic data. These compounds were tested for analgesic and anti-inflammatory activity. All the new compounds showed good analgesic and anti-inflammatory activity. A simple and facile method for the cleavage of benzyl ethers using I(2) in trigol is also reported.
Assuntos
Anti-Inflamatórios não Esteroides/síntese química , Anti-Inflamatórios não Esteroides/isolamento & purificação , Flavonoides/síntese química , Flavonoides/isolamento & purificação , Ochnaceae/química , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Bioensaio , Avaliação Pré-Clínica de Medicamentos , Edema/tratamento farmacológico , Flavonoides/farmacologia , Ligação de Hidrogênio , Camundongos , Estrutura Molecular , Medição da Dor/efeitos dos fármacos , Ratos , EstereoisomerismoRESUMO
Phytochemical investigation of the fruits of Schisandra chinensis led to the isolation of 13 lignans including schisandrene (13), a new lignan based on a dibenzocyclooctadiene backbone with an exocyclic double bond. Its structure and absolute configuration were established using NMR, MS, and CD data. Antioxidant activity of the lignans was evaluated using a DCFH-DA cellular-based assay. The structure-activity relationships of the dibenzocyclooctadiene lignans showed that the exocyclic methylene functionality was essential for antioxidant activity, with the benzoyloxy group probably enhancing such effects.
Assuntos
Antioxidantes , Ciclo-Octanos , Lignanas , Plantas Medicinais/química , Schisandra/química , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Ciclo-Octanos/química , Ciclo-Octanos/isolamento & purificação , Ciclo-Octanos/farmacologia , Coreia (Geográfico) , Lignanas/química , Lignanas/isolamento & purificação , Lignanas/farmacologia , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
The dichloromethane-methanol (1/1) extract of the stem bark of Turraeanthus africanus (Meliaceae) showed remarkable antimicrobial activity against Cryptococcus neoformans, Staphylococcus aureus and methicillin-resistant S. aureus. Phytochemical investigation of this extract afforded six new diterpenoid derivatives, (+)-16-acetoxy-12,15-epoxylabda-8(17),12,14-triene ( 3), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin A, 4), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin B, 5), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin C, 6), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin D, 7) and (12 S,13 S,15 R)-12,15-epoxy-15-methoxy- ent-labd-8(17)-en-16-al (turraeanin E, 9) together with the known compounds, 15,16-epoxy- ent-labda-8(17),13(16),14-triene ( 1), (+)-pumiloxide ( 2), ent-labda-8(17),12 ( E)-diene-15,16-dial ( 8) and 16-acetoxy-12( R),15-epoxy-15beta-hydroxylabda-8(17),13 (16)-diene ( 10). Compound 10 was obtained as its acetoxy derivative ( 10a) and compound 11 was the product of hydrolysis of 6. Antimicrobial activity of the isolates was assayed and compounds 8, 9, 10a and 11 exhibited significant activities.
Assuntos
Antibacterianos/farmacologia , Antivirais/farmacologia , Diterpenos/química , Diterpenos/farmacologia , Meliaceae/química , Antibacterianos/química , Antivirais/química , Candida albicans/efeitos dos fármacos , Cryptococcus neoformans/efeitos dos fármacos , Resistência a Meticilina , Estrutura Molecular , Fitoterapia , Casca de Planta/química , Caules de Planta/química , Staphylococcus aureus/efeitos dos fármacosRESUMO
The methanolic extract of rhizome of Himalayan rhubarb Rheum emodi displayed mild yeast as well as mammalian intestinal alpha-glucosidase inhibitory activity. However, further fractionation of active extract led to the isolation of several potent molecules in excellent yields, displaying varying degrees of inhibition on two test models of alpha-glucosidase. Rhapontigenin, desoxyrhapontigenin, chrysophanol-8-O-beta-d-glucopyranoside, torachrysone-8-O-beta-d-glucopyranoside displayed potent yeast alpha-glucosidase inhibition. However chrysophanol-8-O-beta-d-glucopyranoside, desoxyrhaponticin and torachrysone-8-O-beta-d-glucopyranoside displayed potent to moderate mammalian alpha-glucosidase inhibitory activity. Other compounds displayed mild activity on both the tests. Except desoxyrhapontigenin and rhapontigenin that increased Vmax, other compounds including crude extract decreased the Vmax significantly (p<0.02) in yeast alpha-glucosidase test. Further kinetic analysis on mammalian alpha-glucosidase inhibition showed that chrysophanol-8-O-beta-d-glucopyranoside, desoxyrhaponticin and torachrysone-8-O-beta-d-glucopyranoside may be classified as mixed-noncompetitive inhibitors. However, desoxyrhapontigenin and rhapontigenin may be classified as modulators of enzyme activity. Presence and position of glycoside moiety in compounds appear important for better inhibition of mammalian alpha-glucosidase. This is the first report assigning particularly, mammalian intestinal alpha-glucosidase inhibitory activity to these compounds. Chrysophanol-8-O-beta-d-glucopyranoside, desoxyrhaponticin, desoxyrhapontigenin and rhapontigenin have been isolated in substantial yields from R. emodi for the first time. Therefore, these compounds may have value in the treatment and prevention of hyperglycemia associated diabetes mellitus.
Assuntos
Inibidores Enzimáticos/farmacologia , Inibidores de Glicosídeo Hidrolases , Rheum/química , Animais , Ligação Competitiva , Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus/prevenção & controle , Inibidores Enzimáticos/isolamento & purificação , Inibidores Enzimáticos/uso terapêutico , Hiperglicemia/tratamento farmacológico , Hiperglicemia/prevenção & controle , Mucosa Intestinal/metabolismo , Cinética , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Ratos , Estilbenos/química , Estilbenos/farmacologia , Leveduras , alfa-Glucosidases/isolamento & purificação , alfa-Glucosidases/metabolismoRESUMO
Piper nigrum finds an extensive application in antibacterial preparations belonging to Ayurvedic system of medicine. A bioguided extraction and fractionation of the petroleum ether extract of the berries of P. nigrum afforded 2E, 4E, 8Z-N-isobutyleicosatrienamide (1), pellitorine (2), trachyone (3), pergumidiene (4) and isopiperolein B (5). Pergumidiene and trachyone are isolated for the first time from P. nigrum. All the isolated compounds were active against Bacillus subtilis, Bacillus sphaericus, and Staphylococcus aureus amongst Gram + ve bacteria, and Klebsiella aerogenes and Chromobacterium violaceum among Gram -ve bacterial strains.