RESUMO
Gambir (asen'yaku in Japanese), an aqueous extract of leaves and young twigs of Uncaria gambir Roxb., has traditionally been used as a treatment for diarrhea and dysentery as an internal medicine and for sore throat as a gargle. Although it is a pharmacopoeic medicine in Japan, the quantitative evaluation of its constituents has not yet been adopted in the Japanese pharmacopoeia. We analyzed polyphenolic constituents in 31 gambir and related products to establish evaluation methods, since gambir contains large amounts of polyphenolic constituents. The total flavan contents in the samples revealed using the vanillin-HCl estimation method ranged from 24-79%. Reversed-phase high performance liquid chromatography (RP-HPLC) analysis indicated that catechin was the most abundant constituent in each sample, with contents in the range of 7-76%. The catechin contents in the gambir products between the first and third quartiles were 28-54%. Thus, the lower limit of the catechin content in gambir products can be set at around 20% for quality management. Fifteen tested samples were subjected to HPLC analysis to show the presence of epicatechin (1.5% on average) and the dimeric compounds procyanidin B1, procyanidin B3, and gambiriin A1 (ca. 1% each). The molecular weight distributions of polymeric flavans in the gambir products were analyzed by gel permeation chromatography (GPC) and showed that the average degree of polymerization for each sample was 3 to 7. These results indicate that the combination of the vanillin-HCl method, RP-HPLC analysis, and GPC analysis gives valuable information for evaluating the polyphenolic profiles of gambir products.
Assuntos
Flavonoides/análise , Fenóis/análise , Extratos Vegetais/química , Plantas Medicinais/química , Uncaria/química , Catequina/análise , Técnicas de Química Analítica/métodos , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , PolifenóisRESUMO
Zanthoxylum piperitum (Rutaceae) is used as a spice and a natural medicine in Japan. Our study found that ZP-CT-A, a polymeric proanthocyanidin purified from the fruit of this species, noticeably decreased the minimum inhibitory concentrations of beta-lactam antibiotics for methicillin-resistant Staphylococcus aureus (MRSA). The structure of ZP-CT-A was characterized on the basis of (13)C NMR and size exclusion chromatographic data and the results of thiolytic degradation. A mechanistic study of the effects of ZP-CT-A indicated that it suppressed the activity of beta-lactamase and largely decreased the stability of the bacterial cell membrane of MRSA, as shown by a reduction in the tolerance of MRSA to low osmotic pressure and high ionic strength solutions.
Assuntos
Antibacterianos/farmacologia , Biflavonoides/farmacologia , Catequina/farmacologia , Flavonoides/química , Frutas/química , Resistência a Meticilina , Fenóis/química , Proantocianidinas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Zanthoxylum/química , Antibacterianos/química , Antibacterianos/isolamento & purificação , Biflavonoides/química , Biflavonoides/isolamento & purificação , Catequina/química , Catequina/isolamento & purificação , Proliferação de Células , Espectroscopia de Ressonância Magnética , Resistência a Meticilina/efeitos dos fármacos , Estrutura Molecular , Concentração Osmolar , Oxacilina/farmacologia , Polifenóis , Proantocianidinas/química , Proantocianidinas/isolamento & purificação , Staphylococcus aureus/citologia , Relação Estrutura-Atividade , Compostos de Sulfidrila/química , Inibidores de beta-Lactamases , beta-Lactamases/metabolismoRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) often acquires multi-drug resistance and is involved in many cases of disease in hospitals. We investigated natural substances directly effective against MRSA or that influence antibiotic resistance. Aloe-emodin, an anthraquinone, and several licorice flavonoids showed potent antibacterial effects against MRSA. Like some hydrolysable tannins (corilagin and tellimagrandin I) and a tea polyphenol [(-)-epicatechin gallate], the licorice flavonoid licoricidin also restored the effects of oxacillin, a beta-lactam antibiotic against MRSA. Further study revealed that theasinensin A, a polyphenol formed from (-)-epigallocatechin gallate, proanthocyanidins obtained from fruits of Zizyphus jujuba var. inermis, and polymeric proanthocyanidins from fruit peels of Zanthoxylum piperitum also suppressed the antibiotic resistance of MRSA.
Assuntos
Flavonoides/farmacologia , Resistência a Meticilina , Fenóis/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Taninos/farmacologia , PolifenóisRESUMO
Six aliphatic acid amides (1-6) were isolated from the pericarp of Zanthoxylum piperitum fruits. MS and NMR spectroscopic investigation revealed that these compounds have a ketone and/or hydroxyl group(s) in the unsaturated aliphatic acid moiety of the structure of the amides. Combinations 3-4 and 5-6 are stereoisomers in terms of the relative configurations of their two asymmetric carbons.
