STUDIES ON GLYCOSIDES ⅤⅢ.TOTAL SYNTHESIS OF NEW ALKALOID GLYCOSIDES FROM SELAGINELLA DOEDERIENII

Two new alkaloids,hordenine-O- -L-rhamnopyranoside(Ⅰ)and hordenine -0-(6′-trans-cinnamoyl)-4′-O-β-D-glucopyranosyl- -L-rhamnopyranoside(Ⅲ) isolated from Selaginella doederleinii have been synthesized the first time. A new method,in which trifluoroacetoxyl group was used both as a good leaving group and a protecting group for synthesis of O-glycosides with high stereo- selectivity was reported.

Effect of Potato Extract on its Phenolic Metabolism,SAGs Accumulation and Allelopathic Autotoxicity

[Objective] The paper was to study the effect of potato extract on its phenolic metabolism,SAGs accumulation and allelopathic autotoxicity.[Method] With water treatment as control,the effects of aqueous extracts of potato bud,leaf-stem and tuber on its morphological characteristics,phenolic metabolism,glycoside alkaloids accumulation and allelopathic autotoxicity were studied.[Result] After the treatment of aqueous extract,the germination rate of potato reduced,germination was delayed,the plants became smaller,and the growth of root slowed down;the content of phenolic substances in roots,stems and leaves of potato increased,glycoside alkaloids accumulated,the activity of PPO and PAL increased.The effects of aqueous extract treatment on germination,growth,phenolic metabolism,glycoside alkaloid content and allelopathic autotoxicity successively were bud extractleaf-stem extracttuber extractcontrol.Treatment of aqueous extract did not affect the distribution of phenolic substances and glycosidic alkaloid in potato.[Conclusion] Phenolic substances and glycosidic alkaloid involved in the allelopathic autotoxicity of aqueous extract of potato,which had inhibition effect on germination and growth of potato.

Unprecedented C_(19)-diterpenoid alkaloid glycosides from an aqueous extract of“fu zi”:Neoline 14-O-L-arabinosides with four isomeric L-anabinosyls

Four structurally unprecedented aconitane-type C_（19）-diterpenoid alkaloid glycosides with isomeric arabinosyls, named aconicarmichosides A–D（1–4）, were isolated from an aqueous extract of ＂fu zi＂, the lateral roots of Aconitum carmichaelii. Their structures were determined as neoline 14-O-a-and 14-O-b-L-arabinopyranosides（1 and 2） and 14-O-a-and 14-O-b-L-arabinofuranosides（3 and 4）, by spectroscopic and chemical methods including 2D NMR experiments and acid hydrolysis. Compounds 1–4 represent the first examples of glycosidic diterpenoid alkaloids.

Indole alkaloid glycosides with a 1′-(phenyl)ethyl unit from Isatis indigotica leaves

Seven indole alkaloid glycosides containing a 1′-(4″-hydroxy-3″,5″-dimethoxyphenyl)ethyl unit(1-7)were isolated from an aqueous extract of Isatis indigotica leaves(da qing ye).Their structures were determined by spectroscopic data analysis combined with enzymatic hydrolysis as well as comparison of their experimental CD(circular dichroism)and calculated ECD(electrostatic circular dichroism)spectra.Based on analysis of[α]D20 and/or Cotton effect(CE)data of 1-7,two simple roles to assign location and/or configuration ofβ-glycopyranosyloxy and 1′-(phenyl)ethyl units in the indole alkaloid glycosides are proposed.Stereoselectivity in plausible biosynthetic pathways of 1-7 is discussed.Compounds 3 and 4 and their mixture in a 3:2 ratio showed activity against KCNQ2 in CHO cells.The mixture of 5 and 6(3:2)exhibited antiviral activity against influenza virus H1 N1 PR8 with IC5064.7μmol/L(ribavirin,IC5054.3μmol/L),however,the individual 5 or 6 was inactive.Preliminary structure-activity relationships were observed.