Studies On Chemical Constituents And Antioxidant Activity Of Bidens Biternata

Bidens L.is a plant of Compositae,It widely distributed in tropical and subtropical areas of Asia and America.It is mainly distributed in North China,East China,central China,South China and southwest China.As a traditional Chinese folk herbal medicine,Bidens has a very high medicinal value.Whole grass can be used in medicine,with the effects of clearing away heat and detoxification,promoting blood circulation and removing blood stasis,as well as can be used to treat upper respiratory tract infection,sore throat,acute appendicitis,acute yellow constant hepatitis,gastroenteritis,rheumatism,joint pain,malaria,external use for sore boils,snake bites,bruises and many other diseases.In recent years,many scholars have studied the chemical constituents and pharmacological activities of many species of Bidens L.There are diverse chemical structures in Bidens L.,such as flavonoids,phenylpropanoids,polyacetylenes,steroids,terpenes and the other components.Bidens.biternata is a common species of Bidens L.It is considered as a potential health product that has a wide range of medicinal value.However,there are few studies on the chemical constituents of Bidens.biternata at home and abroad.In order to further develop and utilize of Bidens L.,our research group systematically separated and purified the ethanol extract.These structures have been elucidated on the basis of spectroscopic methods and the activities have been evaluated.We hope to find precursors with drug activity that provide scientific basis for new drug research and development.Objective:In order to provide scientific basis for the research and development of new drugs,our research group systematically separated and purified the Bidens.biternata.Methods:10 kg of Bidens bipinnata was dried and crushed,soaked in different concentrations?95%,75%,50%?of ethanol which removed from extracting ethanol by distillation that successively extracted and concentrated with petroleum ether,chloroform and n-butanol.Chloroform and n-butanol got combined and dissolved with methanol.Isolation and purification were carried out through various chromatographic techniques such as silica gel column chromatography,Reversed phase chromatography,Sephadex LH-20,thin-layer chromatography and preparative high performance liquid chromatography to obtain the pure compounds.Structures of purified compounds were determined by various spectral data,such as 1D-NMR,2D-NMR,HRMS,HPLC,UV,and IR analyses.Antioxidant activity of flavonoids was screened by DPPH free radical scavenging experiment.Results:There are Thirty-six compounds isolated from the experiment that included eighteen flavonoids,four organic acids,two phenylpropanoids,four polyacetylenes and ten other components.Among these compounds,six compounds were isolated from Bidens L.for the first time,and eighteen compounds were isolated from Bidens biternata for the first time,as well as another four novel compounds as following:4-O-?3"-O-Acetyl-6"-O-p-coumaroyl-?-D-glucopyranosyl?-p-coumaric acid,4-O-Methyl Okanin 4'-O-?-D-?4",6"-diaceyyl?-glucopyranoside,2-Furanoctanoic acid,2,5-dihydro-5-oxo-,methyl ester,ethyl?9Z,11Z?-8-hydroxyheptadeca-9,11-dienoate.Antioxidant activity of eighteen flavonoids was screened by DPPH free radical scavenging experiment?Compounds of 2,6-22?.VC was used as positive control.The results showed that the clearance rate was only 8.59%when the concentration of compound 11 was 1000 ug/ml.The scavenging ability of other compounds increased with the increase of concentration.The antioxidant ability of compound 15:okanin 4'-O-?-D?4,6"-diacetyl?-glucopyranoside was similar to that of VC,and the EC₅₀value was 38.58ug/ml.Compounds of 6?17 also have significant antioxidant activity.EC₅₀:47.58 ug/m L?46.68 ug/m L.Conclusions:1.Thirty-six compounds were identified by systematic isolation of extracting ethanol from Bidens biternata.It covered eighteen flavonoids,four organic acids,two phenylpropanoids,four polyacetylenes and ten other compounds.2.There are four new compounds among them as following:4-O-?3"-O-Acetyl-6"-O-p-coumaroyl-?-D-glucopyranosyl?-p-coumaric acid,4-O-Methyl Okanin 4'-O-?-D-?4",6"-diaceyyl?-glucopyranoside,2-Furanoctanoic acid,2,5-dihydro-5-oxo-,methyl ester,ethyl?9Z,11Z?-8-hydroxyheptadeca-9,11-dien oate.3.There are many flavonoids in Bidens bipinnata.Through the preliminary screening of antioxidant activity,compound 15,okanin 4'-O-?-D?4",6"-diacetyl?-glucopyranoside)has a strong antioxidant activity.