| Premna fulva Craib belongs to the genus of premna and Verbenaceae family,distributing in west-northern of Guangxi Zhuang Automumous Region, southerndistrict of Guizhou province and Yunnan province. Chemical compositions ofPremna fulva Craib are complicated, which the flavonoind, triterpenoid, andphenolic were found. More attentions were paid to it, for which has theanti-tumor, anti-inflammation, analgesic properties, and protective effect ofsciatic nerve bioactivities.In this paper, the chemical compositions, the total flavonoids extractprocess and its anti-oxidant activities were studied:(1) Liquid-liquid extraction, and chromatographic methods, such asmacroporous resin, silica gel, polyamide, sephadex LH-20, prep. HPLC, andprep. TLC were utilized to isolated the chemical compositions in Premna fulvaCraib. The eight compounds were isolated from Premna fulva Craib, whichstructures were confirmed by physical and chemical characters andspectroscopic methods. They are identified with inorganic salt KNO3, glucose, spiro[androst-5-ene-17,1'-cyclobutan]-2'-one,3-hydroxy-(3β,17β)-Dinundecanephthalate, vanillic acid, apigenin, naringenin, and 6,8-di-C-glucosylapigenin(vicenin 2). Vicenin 2 was isolated from Premna fulva Craib for the first time.(2) The chemical constituents and pharmaceutical activity of Premna fulvaCraib were reviewed. The isolation and purification methods of flavonoids weresummarized. Finally the free radical scavenging activity and structure-activityrelationships were also summarized.(3) The extracting process of total flavonoids in Premna fulva Craib wasstudied by conventional method Sohlex and modern extracting methods, such asmicrowave assisted extraction, ultrasonic extraction and inner vaporationextraction. The content of total flavonoids in Premna fulva Craib was measuredby UV spectrophotometer with vicenin 2 as reference, wavelength at 282nm.The content and recovery data of total flavonioids extract by four methods werecompared. The results showed that the yield ratio of three optimal methods are2.07%, 1.90%, 1.78%, respectively. The RSD are 1.40%, 1.47%, 1.16%,respectively. The recovery are 100.60%, I05.12%, 99.92%, respectively. Theyield ratio of Sohlex is 0.95%. The modem methods are better than Sohlexmethod.(4) For the anti-oxidant activity, the total flavonoids extract and purifiedflavonoids were studied through lipid peroxidation method. The results showedthat the total flavonoids indicated no significant effect and the anti-oxidationactivity of apigenin and naringenin have linear correlation with their concentrations. Its' IC50 values are 1.45×10-4mol/L, 1.26×10-4mol/L respectively.Vicenin 2 showed no significant anti-oxidant effect but pro-oxidant at highconcentration. Theoretical methods including structure-activity relationships andquantum chemieal calculations were used to elucidate the free radicalscavenging activity differences of the three flavonoids.
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