Studies On Chemical Constituents And Quality Standards Of A.megalophylla Diels Et.Gilg

The tender stem and leaves of A.megalophylla Diels et.Gilg have been made into a healthy tea, it possesses the effect of reducing hypertension and cholesterol. The main chemical constituents of the plant are flavonoids, today studies have been concerned on its effects for controlling high blood pressure. The main valid compound of MEI-CHA is the ampelopsin. Recent pharmacological studies indicates that the intracellar Ca2+-depent component of NE-induced aortic ring contraction can be inhibited by the ampelopsin, and it is low toxicity. It will be of benefit to directing clinical practice and to developing to a new drug. But the research of its chemical constituents and quality standards is very limited in plants. This thesis deal with their chemical study and quality evaluation of this plant, our studies included three parts as follows:l.ReviewThoroughly review previous domestic and external studies on chemical constituents, pharmacology of the 15 Ampelopsis in our country, we draft out a concise and conceive summarize of them, and make a prospect for its developments.2. Study on chemical constituentsThe ethanol extract from the A.megalophylla was separated by column chromatography. We isolated and purified the chemical constituents of A.megalophylla by solvent extraction and column chromatography. As a result, 3 compounds were isolated and identified by using physicochemical properties, spectral analysis (UV, IR, MS, 1H-NMR, 13C-NMR) and hydrolysis products. They were ampelopsin, myricetin and myricetrin. Among these compounds, myricetin and myricetrin are isolated from this plant for the first time. Four kinds of screening test such as column chromatograph, thin layer chromatography, HPLC, and recrystalization we have done for high purity chemical to control the plant. In suchway standard substances with the purity of 98.5% proved by HPLC were got. 3. Study on quality standardsOn the basis of the study of the chemical constituents, we choose the ampelopsin and myricetin as the reference substances for qualitative and quantitative analyses of the plant. The contents of the total flavonoids were determined by UV, and the contents of Ampelopsin and myricetin were separately determined by RP-HPLC. Ⅰ .Qualitative analysesWe have built a TLC identification method of the plant with ampelopsin and myricetin as the standard substances, which proved to be a specific method. The qualitative controlling methods were studied by both thin-layer chromatography and HPLC, both of the methods were available to qualitative analyses of A.megalophylla, the thin-layer chromatography method is selected because it is simpler than HPLC method.Ⅱ.Determination of the total flavonoidsThe total flavonoids were determinated by UV-VIS spectrophotometric methods. Ampelopsin was adopted as a contrast. The standard solution of ampelopsin was diluted to several solutions with different concentration, whose absorbencies were determined respectively at 311nm. Ⅲ. Determination of the ampelopsin and myricetinRP-HPLC was used to determine the content of ampelopsin and myricetin in MEICHA for the first time. The separation was performed on ODS column(Zorbax SB-C18 (250mm × 4.6mm,5μm) ). Determinate and compare the contents of the flavonoids in different parts of the plant.Ampelopsin: With methanol-water-phosphoric acid (35:65:0.2) as a mobile phase and wavelength of UV detector was 292nm, flow rate: 0.7mL/min. The linearity of the method was well with the average recovery of 101.24%.Myricetin: With acetonitrile-water-phosphoric acid (20:80:0.2) as a mobile phase and wavelength of UV detector was 254nm, flow rate: 1.0mL/min. The linearity of the method was well with the average recovery of 101.10%.Results show that total flavonoids are 33.7%, ampelopsin is 27.26% and myricetin is 4.56%. and the contents of ampelopsin in the leaves are higher than those in other part. The content in the leaf comes to the highest. The result shows that the qualitative and quantitative analyses of flavonoids with TLC, UV and HPLC in A.megalophylla was inwestigated, a...