ABSTRACT
Objective: To study the chemical constituents of Stemona tuberosa. Methods: The chemical constituents were isolated and purified by chromatography with RP-C18, silica gel, Sephadex LH-20 and semi-preparative HPLC, and their structures were identified by analysis of spectroscopic data and physicochemical properties as well as relevant references. Results: Ten compounds were isolated from the roots of S. tuberosa, and they were elucidated as 6-methoxy-3-methyl-2H-pyran-2-one (1), stilbostemin A (2), stilbostemin K (3), stilbostemin P (4), stilbostemin Q (5), stilbostemin R (6), stilbostemin T (7), stilbostemin W (8), stilbostemin X (9) and stilbostemin Y (10). Conclusion: Compound 1 is the new pyrone derivative named as stemonapyrone A. Compounds 2 and 3 are isolated from the plant of S. tuberosa for the first time.
ABSTRACT
Objective: To study the influence of different pretreatment methods of grapevine on the content of stibenoids in grapevine. Methods: The concentration of resveratrol and ε-viniferin was determined by HPLC, the fresh grapevine sample after picked was pretreated by different methods such as drying in the shade, drying in a dryer under different temperature, keeping in cold storage, slicing, pulverization, or whole treating, and the dynamic changes of stilbenoids in grapevine was investigated. Results: The contents of resveratrol and ε-viniferin in the fresh sample were very low, but the contents of resveratrol and ε-viniferin in the grapevine after picked would change significantly if treated as drying in the shade with whole branch, especially the content of resveratrol would rise from 0.063 mg/g to 7.175 mg/g with the extension of treating time, and the content of ε-viniferin would rise from 0.838 mg/g to 4.225 mg/g, but at some extent, the content would decline. The contents of resveratrol and ε-viniferin would not rise if the sample was pretreated as drying in the shade after slicing, drying in a dryer or keeping in cold storage. Conclusion: The influence of different pretreatment methods to the contents of resveratrol and ε-viniferin is very large, during drying process in the shade with whole branch, the contents of resveratrol and ε-viniferin change obviously and display the tendency of increasing at the earlier phase of the drying process, and then decrease with the extension of time. The contents of resveratrol and ε-viniferin can reach the level of utilization with the pretreatment of drying process in the shade.
ABSTRACT
In our previous study, we isolated from chloroform extract of the bulbs of orchid P. michuacana, three antioxidant compounds: two stilbene alpha-alpha´-dihydro, 3´,5´,2-trimethoxy-3-hydroxy-4-acetyl-4´-isopentenyl stilbene, 5-[2-(3-hydroxy-5-methoxyphenyl)ethyl]-2-methoxyphenol (gigantol) and one phenanthrene 4,6,7-trihydroxy-2-methoxy-8-(methylbut-2-enylphenanthren-1-1´-4´,6´,7´-trihydroxy-2´-methoxy-8´-(methylbut-2´-enyl)-phenanthrene. Following the study, we investigated the ability of isolated compounds to inhibit advanced glycation in vitro. Bovine serum albumin was glycated in the presence of glucose or methylglyoxal. Amadori-rich protein was prepared by dialyzing lysozyme that had been glycated by ribose. We also evaluated renal function by checking formation of advanced glycation and tail tendon collagen quality in streptozotocin-induced diabetic mice. Also determined the effect on LDL and hemoglobin. Compounds can efficiently inhibit the formation of AGEs by trapping reactive methylglyoxal and showed potent anti-Amadorin activity. Also exhibited a significant inhibitory activity on the glycated hemoglobin (GHb and HbA1c). Compounds showed a protective renal effect and reduction in mice tail tendon collagen. Also the tested compounds are potent agents for protecting LDL against oxidation and glycation. We concluded that compounds from P. michuacana are potent antiglycation agents, which can be of great value in the prevention of diabetic glycation-associated-pathogenesis.
En un estudio anterior, aislamos del extracto clorofórmico de los bulbos de la orquídea Prosthechea michuacana, tres compuestos antioxidantes: los estilbenos alfa-alfa´-dihidro, 3´,5´,2-trimethoxi-3-hidroxi-4-acetil-4´-isopentenil-stilbeno, 5-[2-(3-hydroxy-5-methoxyphenyl)ethyl]-2-methoxyphenol (gigantol) y el fenantreno 4,6,7-trihidroxi -2-methoxi-8-(metilbut-2-enilfenantren-1-1´-4´,6´,7´-trihidroxi-2´-metoxi-8´-(metilbut-2´-enil)-fenantreno. Continuando con el estudio, investigamos la capacidad de estos compuestos para inhibir la glicación avanzada in vitro. La seroalbúmina bovina se glicosiló en presencia de glucosa o metilglioxal. La reacción de Amadori se determinó con lisozima glicosilada previamente tratada con ribosa. También se evaluó la función renal mediante la formación de la glicación avanzada y la inhibición de AGEs en el ensayo sobre el colágeno del tendón de la cola en ratones con diabetes inducida con estreptozotocina. También determinamos el efecto de los compuestos aislados sobre LDL y hemoglobin. Los compuestos pueden inhibir eficazmente la formación de AGE atrapando el metilglioxal reactivo y muestran potente actividad anti Amadorin. También mostraron una actividad inhibitoria significativa en la formación de la hemoglobina glucosilada, GHB y HbA1c. Mostraron un efecto protector renal y una reducción en el colágeno glicosiladó del tendón de la cola. También estos compuestos son potentes agentes para la protección de LDL frente la oxidación y la glicación. En base a los resultados obtenidos se concluye que los compuestos aislados son potentes agentes antiglicación, que pueden ser de gran valor en la prevención de la patogénesis de la diabetes asociada a la glicación.