| Rabdosin serra (Maxim.) Hara is a common Chinese herbal medicine, which was mainlyproduced in provinces south of Yangtze River, such as Hubei, Sichuan, Yunnan, Jiangxi,Guangdong, Guangxi, Fujian, etc. It can clear heat, remove jaundice, be used as cholagogue,as well as cure acute icteric hepatitis and acute cholecystitis.Polyphenols are main active constituents of Rabdosin serra (Maxim.) Hara, it’s widelyused in food, cosmetic, pharmaceutical and other fields. In recent years, extractions ofpolyphenols from plants are becoming research hotspots. In this article, untrasonic extractiontechnology of polyphenols from Rabdosin serra (Maxim.) Hara was studied to get an optimalextraction conditions. Macroporous resin was used to study the purification of polyphenolsextract. Besides, biological properties of polyphenols from Rabdosin serra (Maxim.) Harawas studied, such as oxidation resistance, bacteriostasis and alpha glucoside enzymeinhibition. Besides, active consitituents which has antioxidant activities were identifiedpreliminarily.The main research contents are as follows:(1) Optimization of untrasonic extraction technology of polyphenols from Rabdosin serra(Maxim.) HaraAn orthogonal array design was used to optimize the ultrasonic extraction conditions ofRabdosia serra (Maxim.) Hara. The total polyphenol content was determined by theFolin-Ciocalteu assay, and the influence of ethanol concentration, solid-liquid ratio,temperature, ultrasonic power and time on the extraction efficiency were studied. Resultsshowed that the optimum extraction conditions were as follows:25minutes ultrasonictreatment at225W power for extracting the raw material with a10-fold volume of60%aqueous ethanol solution at40℃. The yield of polyphenol was (6.81±0.11)%under theoptimum condition. The DPPH radical scavenging capability assay showed that the Rabdosiaserra (Maxim.) Hara had strong radical scavenging capability, and its IC50value was38.47μg/mL.(2) Macroporous Resin Adsorption for Seperation of Polyphenols from Rabdosia serra(Maxim.) Hara The adsorption and desorption rates of polyphenols from Rabdosia serra (Maxim.) Harawere used as indexes to compare ten kinds of macroporous resins, and the AL-1was provedto be the best resin and used to optimize adsorption and desorption conditions of polyphenolsfrom Rabdosia serra (Maxim.) Hara. Results showed that the best adsorption conditions were:loading sample concentration of polyphenols520μg/mL, sample pH4, loading flow rate0.8mL/min. The best desorption conditions were: concentration of ethanol80%, desorptionvelocity0.5mL/min.(3) Research on antioxidant activities of polyphenol extracted from Rabdosia serra (Maxim.)HaraAntioxidant activities of polyphenol extracted from Rabdosia serra (Maxim.) Hara werestudied. DPPH radical scavenging assay, H2O2scavenging assay, reducing power assay,β-carotene bleaching assay and inhibition of linoleic acid peroxidation assay were conductedto study the antioxidant activities of polyphenol from Rabdosia serra (Maxim.) Hara, and VCwhich was used as a positive control. Results showed that the antioxidant activities ofpolyphenol from Rabdosia serra (Maxim.) Hara were better than that of VC. The IC50value ofpolyphenol from Rabdosia serra (Maxim.) Hara for DPPH radical scavenging assay, H2O2scavenging assay, β-carotene bleaching assay and inhibition of linoleic acid peroxidationassay were5.00μg/mL,42.51μg/mL and66.58μg/mL respectively. And accordingly, thevalues of VCwere5.99μg/mL,56.74μg/mL and94.83μg/mL respectively. These resultsindicated that the antioxidant activities of polyphenol from Rabdosia serra (Maxim.) Harawere better than that of VC. High performance liquid chromatography (HPLC), ultravioletspectrum scanning and LC-MS was used to indentify the active antioxidant constituents ofpolyphenols from Rabdosin serra (Maxim.) Hara. Results showed that, the main activeantioxidant constituents of polyphenols from Rabdosin serra (Maxim.) Hara were rosemaryacid and chlorogenic acid, and rosemary acid was the most active ingredient.(4) Study on antibacterial activities of polyphenols from Rabdosia serra (Maxim.) HaraOxford cup method was used to study antibacterial activities of polyphenols fromRabdosia serra (Maxim.) Hara. Effects of temperatures, pH, concentrations on actibacterialactivities of polyphenol extracts from Rabdosia serra (Maxim.) Hara and its minimalinhibitory concentrations on different bacteria were studied respectively. Results showed as follows: Rabdosin serra (Maxim.) Hara polyphenols has obvious inhibiting effects on bacterialike Staphyloccocus aureus Rosenbach, E. Coli and Bacillus subtilis, while the inhibitingeffects on fungus like Candida rugosa and Rhizo-mucor miehei has not been found. Andthe comparison of inhibition effects was: Staphyloccocus aureus> Escherichia coli>Bacillus subtilis. Temperatures didn’t have appreciable effects on its antibacterial activities,while the effects of pH were significant. Inhibition ratio was maximum for Staphyloccocusaureus when pH was7, while for E. Coli and Bacillus subtilis, the pH was8. Besides, theMIC of Staphyloccocus aureus Rosenbach, E. Coli and Bacillus subtilis were0.3mg/mL,0.3mg/mL and0.4mg/mL, respectively.(5) Alpha glucosidase inhibiting effects of polyphenols from Rabdosin serra (Maxim.) HaraThe enzyme reaction kinetics equation was established by colorimetric method, andalpha glucosidase inhibiting effects of polyphenols from Rabdosin serra (Maxim.) Hara werestudied. Results showed that the inhibition was reversible and its specific inhibition type washybrid noncompetitive inhibition. Inhibition rate experiments showed that the inhibitoryeffects of Rabdosin serra (Maxim.) Hara increased with the increase of polyphenolsconcentration and gradually reached a stable value. When its concentration was40μg/mL, thealpha glucoside enzyme inhibition rate was43%, closed to the stable value.These research can help to improve the value in use of Rabdosin serra (Maxim.) Haraand provide theoretical basis for its further research and development. |
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