| Polygonum hydropiper(Polygonaceae,Polygonum)was the dry aboveground part of Polygonum hydropiper L.It was widely distributed throughout China,which had been recorded in “List of ethnodrugs in Yunnan province ” and “Catalog of ethnodrugs in Guangxi Zhuang Autonomous Region”.P.hydropiper was neutral in nature and pungent in flavor.In clinic P.hydropiper was applied for the treatment of cold diarrhea,bacillary dysentery,stagnation of dampness,eczema,etc.Furthermore it was wildly applied in the fields of traditional Chinese medical science,agriculture and animal husbandry.Currently,the fundamental researches of P.hydropiper still needed to be improved.In this experiment,the pharmacognosy identificaion,quantitative determination of four flavonoids,optimization of extraction process of total flavones and the antibacterial activity in vitro were carried out.The main research methods and results are as follow:1.The pharmacognostical study research by morphology,tissue and powder characteristics of P.hydropiper were observed and analyzed.From the transverse section of stem,thin cortex,wide pith and 20~30 vascular bundles intermittently arranged into a ring could be seen.From the surface sheet of leaves,glandular and non-glandular hairs could be observed.Most of the stoma are paracytic type,anisocytic and anomocytic type can be found occasionally.In the powders,numerous calcium oxalate clusters arranged in rows or scattered and spiral vessels could be found.Pollen grains were spherical and reticulated,stone cells could be observed occasionally.The results of this study could provide scientific references for authentification,quality standardization and resource utilization of P.hydropiper.2.Physicochemical properties and assaying method of P.hydropiper were developed by HPLC identification.Regard vitexin,hypericin,rutin and isorhamnetin as reference sbstance,the HPLC chromatographic condition were determined as follow: Phenomenex Luna C18(250 × 4.60 mm,5 ?m);column temperature: 35?;acetonitrile and 0.01 % formic acid-water solution(15:85)isocrativ elution;injection volume: 20 ?L;detection wavelength were 370 nm.The standard curve regression equation of vitexin: y = 7,2×106 x-1.7×103(R2=1.0000),linear range: 0.0236~0.2360 mg/m L;hypericin: y = 8.2×106 x +2.3×105(R2=0.9998),linear range: 0.1028~1.0280 mg/m L;rutin: y = 1.1×107x-2.0×104(R2=0.9998),linear range: 0.1040~1.0400 mg/m L;isorhamnetin: y =8.1×106 x-1.3×104(R2=0.9998),linear range: 0.1486 ~ 1.4860 mg/m L.3.To optimize the extraction conditions of total flavonoids from P.hydropiper,on the basis of single-factor tests.Box-Behnken design was used to optimize extraction technology of total flavonoids from P.hydropiper with three factors which were liquid-solid ratio,ethanol concentration and extraction time.The optimal extraction conditions were as follow: ultrasonic extracting with 66% ethanol for three times,37 min for each time,liquid-solid ratio of 38:1(m L: g).Under the optimal condition,the content of total flavonoids was 6.0847 mg/g.4.To evaluate the antimicrobial activity of P.hydropiper,the diameter of inhibition zone of different extracts was determined by cylinder plate method and minimal inhibitory concentration(MIC)was investigated by the broth dilution and plate method.Compared the antimicrobial susceptibility of different extracts on pathogenic E.coli.,ethyl acetate extract showed strongest antibacterial activity,with the inhibition zone diameter of 136.8±0.08 mm,and MIC of 25 mg/m L.The ethyl acetate extract could be considered as the antibacterial active site of P.hydropiper. |
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