Anti-tumour Constituents And Action Mechanism Of Fagopyrum Tataricum Roots

The genus Fagopyrum,a member of family Polygonaceae,comprises 15 species which are mainly distributed in the North Temperate Zone.A total of 10 species occur in China,including three important buckwheat species:Fagopyrum esculentum Moench.(common buckwheat),Fagopyrum tataricum(L.)Gaertn.(tartary buckwheat),Fagopyrum dibotrys(D.Don)Hara.(perennial buckwheat).F.esculentum and F.tataricum are two important crop plants and the main buckwheats consumed all around the world as a potential "functional food" material,particularly with respect to their seeds and seed sprouts due to the abundance of phenolic compounds,high quality proteins and a well balanced amount of essential amino acids and minerals.Detailed comparisons of F.esculentum and F.tataricum revealed that the former has the advantages of sweet taste,large seed size,and easy dehulling of seed coat.In contrast,the latter was of bitter taste,small size,and tight seed coat.Despite of above mentioned disadvantages,F.tataricum has been reported to contain much more phenolics content than F.esculentum,which is therefore being increasingly favored by researchers in recent years.Besides F.tataricum edible uses,F.tataricum has been found use for antioxidant,antitumor,hypotensive,hypoglycemic and hypolipidemic purposes.Phytochemical investigations of this species mainly focused on the seeds and revealed the presence of abundant flavonoids and phenolics.However,F.tataricum roots were utilized to treat some chronic and incurable diseases,such as rheumatic disorders,cancers and general debility.Its roots were also called "Qiao ye qi",indicating that it might have similar effects as "San qi"(Panax notoginseng roots).However,to the best of our knowledge,there has been no report on the chemical constituents and bioactivities of F.tataricum roots,thus being casted away after seeds harvest year by year,though with high biomass,which is really a waste of potential medicinal resource.In this study,we studied the chemical constituents and anti-tumour activities of the roots of F.tataricum.The main contents of our study are as following these aspects:1.1 Study on bioactive components of Fagopyrum tataricum(L.)Gaertn.The roots and roughly powdered material was extracted three times with 80%(v/v)ethanol,under reflux for 2h each time.After removal of the solvent by evaporation,the extracts were suspended in water and partitioned with petroleumether(PE),CH2CI2,EtOAc and n-BuOH,successively.Fagopyrum tataricum(L.)Gaertn.A total of 7 new with 44 known compounds were isolated from CH2Cl2 and EtOAc fractions and their structures were elucidated by detailed spectroscopic analyses on the basis of NMR,IR,and MS data.Additionally,17 compounds were isolated from the genus Fagopyrum for the first time.Lignans were first isolated from the family Polygonaceae.A total of 33 known compounds were isolated from CH2Cl2 fractions of the stems of Fagopyrum tataricum(L.)Gaertn.The major types of the isolated compounds were phenylpropanoid glycosides,flavones,lignans and phenolic small molecular compounds.In the seed of Caragana microphylla Lam..We found phenylpropanoid glycosides are the main activity components and exhibited a significant anti-tumour activity in vitro and vivo.2 Pharmacological research of Fagopyrum tataricum(L.)Gaertn.In vitro,the phenylpropanoid glycosides from the roots of Fagopyrum tataricum were found to possess significant anti-tumour activity.These compounds were evaluated in vitro for their inhibitory ability against the growth of human lung adenocarcinoma(A-549),human colon carcinoma(HCT-116),human breast carcinoma(ZR-75-30)and human promyelocytic leukaemia(HL-60)cell lines.Tatariside C(3),the most active compound,exhibited IC50 values of 6.44-7.49ug/ml against four cell lines.Additionally,the cytotoxic activity seems not related to the number of feruloyl groups,but to the substitution position.It appears that the feruloyl group at C-6' is crucial for cytotoxicity and the activity is weak when it is substituted by coumaroyl or acetoxyl group.To evaluate the safety of tatarisides in vivo,the acute toxicity test was carried out.The ICR mice were administered(i.g.)by 3750 mg/kg tatarisides,but no obvious changes of mortality,clinical signs and body weight were observed during the 14 days observation period.Tatariside F exhibited most activity against SMMC-7721 and HepG-2 with IC50 values of 3.09 and 1.31ug/ml.Additionally,TF displayed excellent p53-MDM2 inhibitory activity with Ki values of 5.9 uM.Comparing the Tatariside F(TF)growth-inhibitory effects in S180 mice by administered(i.p.)and(i.v.),the results is that TF 20mg/kg(i.v.)show the 42.3%(P<0.05)inhibitory rate and inhibitory rate of TF 10mg/kg(i.p.)is 52.1%(P<0.05).So the TF show better effect by administered(i.p.)than(i.v.)in S180 mice.Additionally,the anti-tumour effect of TF combining CTX on H22 bearing mice was carried out.The result is that TF can enhance anti-tumour effect of CTX and reduce its side-effect in H22 mice.The mechanism of anti-tumour is through active P53 to Down-regulation Bcl-2 and Up-regulation Bax.3 Quality evaluation of phenylpropanoid glycosidesThe EtOAc fractions was submitted to sephadex LH-20(MeOH:H2O,8:2)to give tatarisides.Its content is 77.8%by UV determination.In addition,sduty on the determination of four new phenylpropanoid glycosides(Tataeiside A,B,D,F)by HPLC-UV-DAD method were performed in tatarisides for quality evaluation.Tataeiside F is most abundance compound in tatarisides and its content reach to 49%.