Traditional Chinese Medicine Apocynum Leaves Flavonoids Extraction And Separation Of The Study

Apocynum venetum L.(luobuma in Chinese, Apocynaceae)is a wild shrub grown in Asia ,and its leaves have been used as a tea in China,Japan and other Asian countries.The leaves of Apocynum venetum L. have been used as traditional Chinese medicine.It has been reported that the extract from the leaves of Apocynum venetum L. exerts various pharmacological effects including diuretic , antihypertensive, antihyperlipidemic,antidepressed and sedative effects. In order to investigate the material foundation of its activities, the methods of natural pharmaceutical chemistry were used to search for the flavonoid compositions of AV .The main research was aimed to identify the variety of the traditional Chinese medicine, to accumulate and purify the total flavonoid compositions and identify the components from the aqueous extract. To identify the variety of the herbal medicine: Apocynum venetum L.is the varoiety in our research through the characteristic identification,medicine powder microidentification,specific qualification tests and TLC. The extraction and isolation process is as follows: The leaves of Apocynum venetum(3kg) were extracted twice with H2O (20l) for 2h.The two extracts were combined and concentrated under reduced pressure and subjected to chromatography through a MCI—gel(HPD—100)column.Elution with H2O yielded a fraction consisting mainly of sugars,Fr1 .Further elution successively with 20% EtOH ,50% EtOH ,70% EtOH and absolute EtOH yielded Fr2,Fr3,Fr4 and Fr5.Fr3 and Fr5 were combined and concentrated under reduced pressure ,the concentrated aquous extract were adjusted to PH=3, then shaken with EtoAc .The EtoAc layer was concentrated under reduced pressure and chromatographed over a polyamide column and a silica gel columm separately.The polyamide column was eluted with water firstly and yielded Fr1,then futher eluted successively with 5% EtOH,10% EtOH ,30% EtOH,50%EtOH ,70% EtOH and absolute EtOH yielded Fr2,Fr3,Fr4 , Fr5,Fr6and Fr7.The Fr2 was chromatographed repeatedly through polyamide ,Sephadex LH-20to furnish CompoundⅠ,trifolin.The Fr3-1 was chromatographed repeatedly through a dry polyamide column,Sephadex LH-20 to give Compound Ⅱ, Compound Ⅲ,hyperroside, Compound Ⅳ.Repeated chromatography of Fr3-2 with Sephadex LH-20 yielded CompoundⅤ,quercetin(10mg). The silica gel column was eluted with CHCL3-CH3OHwhich yielded Fr3,Fr64-68 and Fr97-136.The Fr3 gave CompoundⅥ,the Fr64-68 was chromatographed through Sephadex LH-20 repeatedly and yielded CompoundⅦ,isoquercetin-6ˊ-o-acetate .Repeated chromatography of Fr97-136 with dry polyamide (EtoAC-CH3OH,2:1) and Sephadex LH-20 yielded CompoundⅧ(10mg),isoquercitrin.The compounds were identified by means of physical,compound methods and instrumental analysis such as IR,H-NMR,C-NMR and MS.