Preliminary Studies On The Chemical Constituents And Quality Control Of Polygonum Chinense L.

Polygonum chinense L. belongs to the genus Polygonum (Polygonaceae). The whole plant of P. chinense is commonly used as a Linglan herbal medicine for the treatment of dysentery, sore throat and hepatitis. It is one of the main ingredients of several cold herbal tea such as "Guangdong tea", "Wang-Lao-Ji", and "Twenty-four herbs".In this thesis, phytochemical investigation on this herb led to the isolation of 14 compounds. The structures of these compounds were elucidated by extensive spectroscopic analyses. The compounds included seven flavonoids:isorhamnetin (1), kaempferol (2), quercetin (3), apigenin (4), luteolin (5), quercitrin (6), and naringenin (7); six organic acids:gallic acid (8), ellagic acid (9), syringic acid (10), caffeic acid (11), protocatechuic acid (12) and methyl p-hydroxybenzoate (13) and one sterol:β-sitosterol (14). Among them, compound 13 was isolated from this plant for the first time.P. chinense was widely used. It was recorded in Chinese Pharmacopeia (1977 Edition), and was included in <> in 2004. However, the fingerprint and quantitative quality control method were not reported.Flavonoid and organic acids were the major components of P. chinense. These kinds of compounds could be well analyzed by capillary electrophoresis. Therefore, we use capillary electrophoresis to establish the fingerprint of P. chinense, We obtained a primary optimized conditions:50mmol/L borax-5% acetonitrile (V/V) solution (pH9.43) as the buffer; injection pressure 0.5 psi, injection time 10s; Separation voltage 20kV; Column temperature 25℃; Detected wavelength 214nm; 0.1 mol/L NaOH (1min), deionized water (5min) and buffer solution (2min) flushing successively before each injection. However, the instrument of capillary electrophoresis in the Analytical center of Jinan University was purchased ten years ago, and was not stable. We didn't get the repeatable fingerprint finally.So we turn to use the classical HPLC method to establish quality control method for P. chinense. During the phytochemial study, we found that this herb had a high content of ellagic acid (EA), and this compound was reported to possess anti-inflammatory, antioxidant, anti-tumor and antiviral activities, which were consistent with the main function of P. chinense. Therefore, ellagic acid (EA) can be used as chemical marker of P. chinense. A quantitative HPLC method was first established to determine the content of ellagic acid in P. chinense. A Welch Materials XB-C18 column (4.6 mm×250 mm,3μm) was used. The mobile phase consisted of methanol and 0.2% formic acid solution at a flow rate of 0.8 mL/min, mobile phase V (methanol):V (volume fraction of formic acid solution for 0.2%)= 45:55. The detection wavelength was set at 357 nm and the column temperature was 30℃. The contents of ellagic acid in ten batches of P. chinense. collected from different areas of Guangzhou were determined. The method was proven to be quick, simple and reproducible. It is quite suitable to be used for the quantitiative quality control of P. chinense.