Studies On The Chemical Composition Of Centipeda Minimca And Helleborus Thibetanus

Centipeda minima is an annual herbaceous plant belonging to the Compositae family.It is distributed widely in mainland China,Australia and Southeast Asian countries.The dry whole plant of C.minima is one of the sources of the traditional Chinese medicine.Its main functions are treating wind and cold,clearing the nose and improving the orifices.It is often used clinically to treat wind-cold,rhinitis,cough,and colds.‘Xiao Tao Er Qi’,the dried roots and rhizomes of Helleborus thibetanus（Ranunculaceae family）,is one of the folk medicines in Shaanxi,China.Xiao Tao Er Qi is widely distributed in the northwest Sichuan,southern Gansu,southern Shaanxi and northwest Hubei of China.It has the effects of clearing heat,reducing swelling and promoting blood circulation,and has obvious anti-tumor,cardiovascular protection,and anti-rheumatic properties.The two herbs not only contain abundant chemical components,but also the monomer compounds show obvious anti-tumor effects.The chemical constituents and biological activity determination of ethanol extracts of C.minima and H.thibetanus were studied in this paper.Thirty five compounds were separated and identified by macroporous resin（D101）,silica gel,Sephadex LH-20,ODS column chromatography,semi-preparative HPLC and other chromatographic methods,combined with one-dimensional(¹H,¹³C),two-dimensional（¹H-¹H COSY,HSQC,HMBC,NOESY）nuclear magnetic resonance and IR,UV,ESI-MS,optical rotation and circular dichroism spectrum data.Fifteen compounds were separated and identified from the ethyl acetate extraction phase of C.minima,including a sterol（1）,a flavonoid（2）,nine sesquiterpenes（3-11）and four thymol derivatives（12-15）.Among them,4 is a new compounds（guaiane sesquiterpenes）.The known compounds are identified as:stigmasterol（1）,3-methoxyquercetin（2）,centiplide A（3）,cenminolide C（5）,cenminolide A（6）,brevilin A（7）,microhenalin C（8）,ainicolide D（9）,minimolide L（10）,minimolide B（11）,8-hydroxy-9-isobutoxy-10（2）-methylbutyryloxy-thy-mol（12）,8-hydroxy-9,10-diisobutyryloxy-thymol（13）,8,9-ene-9,10-isobutyryloxy-thymol（14）and 3-formyloxy-8,9-epoxy-10-isobutyryloxy-thymol（15）.The article uses SRB to study the inhibitory effects of compounds 3 and 7 against human breast cancer cells（MDA-MB-231）,and the results showed that both compounds have moderate cytotoxic activity.Twenty compounds were isolated and identified from Helleborus thibetanus.Five phenolic compounds（16-20）were separated from the ethyl acetate extract phase.Thirteen bufadienoli-des（21-33）and two ecdysterones（34-35）were separated from the n-butanol fraction.Among them,21-23 are new compounds（bufadienolides）.The known compounds are identified as:p-hydroxybenzoic acid（16）,methyl p-hydroxycinnamate（17）,ethyl p-hydroxycinnamate（18）,methyl caffeate（19）,ethyl caffeate（20）,gamabufotalin（24）,5β,10β,14β,16β-tetrahydroxy-19-norbufo-3,20,22-trienolide（25）,hellebrigenin（26）,telocinobufagin（27）,deglucohellebrin（28）,hellebrin（29）,14β-hydroxy-3β-[（β-D-glucopy-ranose）-oxy]-5α-bufa-20,22-dienolide（30）,14β,16β-dihydroxy-3β-[（β-D-glucopyranose）-oxy]-5α-bufa-20,22-dienolide（31）,14β-hydroxy-3β-[（β-D-glucopyranose）-（1→4）-（β-D-gluco-pyranose）-oxy]-5α-bufa-20,22-dienolide（32）,14β-hydroxy-3β-[（β-D-glucopyranose）-（1→6）-（β-D-glucopyranose）-oxy]-5α-bufa-20,22dienolide（33）,（20R,22R）-2β,3β,5β,14α,20,22,25-he-ptahydroxy-5β-cholest-7-en-6-one（34）,（20R,22R）-2β,3β,14α,20,22,25-hexahydroxy-5β-chol-est-7-en-6-one（35）.We screened the anti-angiogenic and anti-tumor activities of cardiac glycosides,and the results showed that 28 and 31 have strong biological activities.