Chemical Compositions Of Polygonum Hydropiper L. And Their Bioactivities

The Polygonum hydropiper L.belongs to Polygonum of Polygonaceae family.In the world,Polygonaceae has 40 genera and 800 species,which are mainly distributed in the north temperate zone and growed at the dicth or water in altitude of 450~1500 meters.China has 11 genera,more than 180 species are distributed in the northern and southern provinces;There are 8 genera,52 species,6 varieties of Polygonum in Qinling Mountains.In China,many species of Polygonum are important resource of the medicines,which is effective medicine for heat clearing and detoxicating,promoting blood circulation and relieving pain,detumescence,antidiarrhea,diuresis and convergence et al..They show good biological activity in antibacterial,antioxidation,anti-tumor,insecticidal and other aspects.It is found that the chemical constituents of this genus are flavonoids,quinones,diphenylethenes,phenylpropanoids,steroids,volatile oils and other compounds.In order to further exploit the medicinal values of the genus,this paper studied on the isolation and identification of Polygonum hydropiper L.from Qinling Mountains for the first time.The bioactivities of these compounds on antibacterial and antioxidation were also evaluated.The air-dried whole herb of Polygonum hydropiper L(13.1 kg).were powdered and extracted with 95 % ethanol.The ethanolic extract was evaporated to give crude extract.The crude extract was then suspended in water and treated with petroleum ether,ethyl acetate and n-butanol to afford the extracts.15 compounds were isolated from the three organic phases by several chromatographic techniques and recrystallization methods,and the compounds 1and 2 was obtained from the petroleum ether phase,the compounds 3~11 was obtained from the ethyl acetate phase,the compounds 12~15 are obtained from the n-butanol phase.By modern spectroscopy and physical or chemical properties analysis,the15 compounds were identified as ?-sitosterol(1),aniba dimer A(2),succinic acid(3),quercetin(4),gallic acid(5),daucosterol(6),quercetin-3-O-?-D-gluco-side(7),kaempferol-3-O-?-D-glucoside(8),quercetin-3-O-?-galactosidase(9),kaempferol-3-O-?-galacto-sidase(10),stigmast-4-ene-3?,6a-diol(11),fumaric acid(12),ellagic acid(13),?-butyl-D-tagatose(14)and quercetin-3-O-(2'-galloyl)-?-D-galactopyranoside(15).The compounds 2,3,8,11~15 were isolated from Polygonum hydropiper L.for the first time,and compounds 3,12,14 were isolated from the genus Polygonum for the first time.The antibacterial activities of the isolated compounds 1,2,4~7 and 9~15were tested.The minimum inhibitory concentrations(MICs)were measured with4 bacterias and 9 plant pathogenic fungis.The results showed that flavonoids and carboxylic acid have good antibacterial effectt to 4 bacterias and 9 plant pathogenic fungis;and quercetin,quercetin-3-O-(2'-galloyl)-?-D-galactopyranoside showed the best activity to restrain the growth of the Staphylococcus aureus with MIC value of 31.2 ?g·mL-1;The different activity of other flavonoids result from their different structures;compound 1,2,6 and 14 showed no significant inhibition on the test bacterias and plant pathogenic fungis.The antioxidation activity of the compounds 5~8,10,12,13 and 15 were tested.With various compounds on DPPH radical scavenging rate to determine its antioxidation ability.The results showed that the antioxidation activity of quercetin,gallic acid,ellagic acid and quercetin-3-O-(2'-galloyl)-?-D-galactopyranoside is stronger than vitamin C;The other flavonoids also showed good antioxidation activity,but because of the difference in structure,the antioxidation activity is different.Therefore,the Polygonum hydropiper L.contain antioxidation substances,can be used as antioxidations for further development and utilization.