Studies On Quality Of Folium Mori And Vasorelaxation-structure Relationship Of Main Compounds

Folium Mori, leaves of Morus alba L., contain varieties of functional compounds, such as amino acids, vitamins, minerals, flavonoids, alkaloids, carbohydrates, steroids, and so on, with activities of exhibiting a wide range of biological effects, including reducing blood glucose, hypertensive, antihyperlipidemia, anti-inflammatory, antioxidant, anticancer, bacteriostasis and antivirus activity. Folium Mori have been widely used as medicine and food.The present study was to study the HPLC fingerprint, contents determination of flavonoids and the separation and purification of total flavonoids of flavonoids of Folium Mori, so as to provide basis for the development of Folium Mori resource. Moreover, the vasodilator activity of Folium Mori extract and the relationship between vasodilation of flavonoids and their retention index (RI) were also investigated.1. Determination of chromatographic fingerprint of Folium Mori by HPLCObjective: To develop the fingerprint determination method for Folium Mori, by HPLC method and to provide basis for identification of Folium Mori.Methods: A RP-HPLC method with gradient elution was used to determine the fingerprints of Folium Mori, from different plant sites, collected time and varieties. Mutual mode was developed, cluster analysis and similarity calculation were taken for comparison of the samples.Results: Samples from different plant sites, collection time and varieties were of high similarity, though a few samples showed evident difference in fingerprint graphics. Samples harvested in winter had even higher similarity than that of other seasons.Conclusion: Fingerprint of Folium Mori, can be an identifying method for Folium Mori.2. Determination of main flavonoids components of Folium MoriObjective: To determine and compare the contents of total flavonoids, chlorogenic acid, rutin, isoquercitrin, quercetin and kaempferol in Folium Mori from different collected time, varieties and plant sites.Method: The contents of total flavonoids was determined by colorimetry.The contents of chlorogenic acid, rutin and isoquercitrin were determined by RP-HPLC. Zorbax SB Cis column(4.6mm><250mm,5um) was used as analysis column, the mobile phase was 90%acetonitrile-0.2%phosphoric acid with gradient elution. The flow rate was 1.0 mL-min"1 , the column temprature and the detection wavelength were set at 25°C,358 nm. The contents of quercetin and kaempferol were determined by another HPLC method, performed on Zorbax SB Ci8 column with the mobile phase consisted methanol-0.20% phosphoric acid solution (55:45, v/v). The flow rate was 1.0 mL-min'1, the column temprature and UV wavelengh were set at 35°C,370nm. Result: The contents of tested components in Folium Mori samples harvested in winter are higher than that of other seasons., while the contents varied obviously among Folium Mori from different plant sites and different varieties.Conclusion: The contents tested components are influenced by collected time, plane site, and varieties.3. Studies on the separation and purification of total flavonoids from Folium Mori, by macroreticular resinObjective: To investigate the technological parameters of the purification process of total flavonoids from Folium Mori, by macroreticular resins.Method: The static absorption capacity,static elution ratio, static elution capacity of twelve types macroreticular resins were studied respectively and compared in order to find the optimum macroreticular resin. The technical process for purification of total flavonoids with the optimum macroreticular resin, was screened by purity and yield of total flavonoids product.Result: Rl type macroreticular resin owned optimum absorption and eluationparameters.The absorption ratio was 111.1 mgg"* . After the optimization, the yield of total flavonois was 76.6% and product purity was 56.0%.Conclusion: The Rl type macroreticular resin showed better comprehensive absorption property. It can be used to purify the extract of Folium Mori..4. Studies on vasodilator activity of Folium Mori extract and the relationship between vasodilation of flavonoids and their retention indexObjective: To investigate the vasodilator activity of Folium Mori extract and the relationship between vasodilation of flavonoids and their retention index (RI).Methods: Vasorelaxation of the flavonoids and Folium Mori extract were measured by measuring the tension reduction by samples in rat thoracic aorta precontracted by phenylephrine (PE) or by KC1. RI values of 18 flavonoids, including flavones, flavonois, flavanones, flavanols and isoflavones were measured by RP-HPLC method based on alkan-2-ones.Results: The RI-Rex regression equation for flavonoids was Rex =-11.68+0.11 RI (n=18,r =0.915, PO.01). Both water extract and ethanol extract caused concentration-dependent relaxation of aorta rings precontricted with K+(P<0.01), vasodilator effect of ethanol extract is greater than that of water extract(P<0.01).Conclusion: Folium Mori extract induces relaxation of aorta rings precontricted with K+.The potency of the vasorelaxation of flavonoids was positive correlated with RI.