Triterpene Glycosides of Scheffleropsis angkae. IV. Structure of Glycosides L-C2 and L-I2

Two new triterpene glycosides of the -amyrin series, L-C ₂ and L-I ₂ , 27-hydroxyursolic acid 3-O--L-arabinopyranoside and its 28-O--L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl ester, are isolated from leaves ofScheffleropsis angkae(Araliaceae). The structures of the glycosides are established using chemical methods and NMR techniques ( ¹ H, ¹³ C, ¹³ C-APT, COSY, TOCSY, HSQC, HMBC, and ROESY).     

PURIFICATION OF GINKGO LEAVES EXTRACT WITH MACROPOROUS ADSORBENT BASED ON UREA-FORMALDEHYDE CONDENSED POLYMERS

I INTRODUCTIONGinkgo biloba L. is one of the important economic trees, which is widely distributed inChina. In recent years, medicinal and healthful preparations based on the extractS from ginkgoleaves have been rapidly developed for the treatment of peripheral circulatory and cerebralinsufficiencyl']. Such eXtracts contain flavonol glycosides and terpene lactones as thepharmacologically active compounds. Organic-solvent extraction is one of the earliest methodsto prepare the extracts o…     

A new hydroxybenzoic acid glycosides from the plant of Trifolium lupinaster

<正>A new 5-O-(β-D-glucopyranosyl)-6'-O-benzoyl-2,5-dihydroxybenzoic acid was isolated from the ethyl acetate extract from the whole plants of Trifolium lupinaster L.Its structure was determined and deduced on the basis of their spectral data.     

A New Cardenolide and Two New Pregnane Glycosides from the Root Barks of Periploca sepium

A new cardenolide and two new pregnane glycosides, periplogenin 3‐[O‐β‐glucopyranosyl‐(1→4)‐β‐sarmentopyranoside] ( 1 ), (3β,20S)‐pregn‐5‐ene‐3,17,20‐triol 20‐[O‐β‐glucopyranosyl‐(1→6)‐O‐glucopyranosyl‐(1→4)‐β‐canaropyranoside] ( 2 ), and (3β,14β,17α)‐3,14,17‐trihydroxy‐21‐methoxypregn‐5‐en‐20‐one 3‐[O‐β‐oleandropyranosyl‐(1→4)‐O‐β‐cymaropyranosyl‐(1→4)‐β‐cymaropyranoside] ( 3 ), were isolated from the root barks of Periploca sepium Bge , together with seven related known compounds, periplogenin, xysmalogenin, (3β,20S)‐pregn‐5‐ene‐3,17,20‐triol, (3β,14β,17α)‐3,14,17‐trihydroxy‐21‐methoxypregn‐5‐en‐20‐one, (3β,20S)‐pregn‐5‐ene‐3,20‐diol 3‐β‐glucopyranoside 20‐β‐glucopyranoside, (3β,20S)‐pregn‐5‐ene‐3,20‐diol 3‐[O‐2‐O‐acetyl‐β‐digitalopyranosyl‐(1→4)‐β‐cymaropyranoside] 20‐[O‐β‐glucopyranosyl‐(1→6)‐O‐β‐glucopyranosyl‐(1→2)‐β‐digitalopyranoside], and (3β,20S)‐ pregn‐5‐ene‐3,20‐diol 20‐[O‐β‐glucopyranosyl‐(1→6)‐β‐glucopyranoside]. Their structures were elucidated on the basis of spectroscopic analyses.     

Glycosidic Constituents of Celastrus orbiculatus

Three new, 1 – 3 , and seven known phenolic and terpenic glycosides were isolated from the BuOH‐soluble fraction of 95% EtOH extract of the roots and rhizomes of Celastrus orbiculatus. The structures of the new compounds were elucidated as carvacrol 2‐O‐α‐L ‐rhamnopyranosyl‐(1→6)‐β‐D ‐glucopyranoside ( 1 ), 5‐methoxycarvacrol 2‐O‐α‐L ‐rhamnopyranosyl‐(1→6)‐β‐D ‐glucopyranoside ( 2 ), and 15‐hydroxytorreyol 10‐O‐β‐D ‐apiofuranosyl‐(1→6)‐β‐D ‐glucopyranoside ( 3 ) on the basis of spectroscopic analysis and chemical methods.     

Presenegenin Glycosides from Securidaca welwitschii

The five new presenegenin glycosides 1 – 5 were isolated from Securidaca welwitschii, together with one known sucrose diester. Compounds 1 – 4 were obtained as pairs of inseparable (E)/(Z)‐isomers of a 3,4‐dimethoxycinnamoyl derivative, i.e., 1 / 2 and 3 / 4 . Their structures were elucidated mainly by 2D‐NMR techniques and mass spectrometry as 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[β‐D ‐glucopyranosyl‐(1→3)]‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 1 ) and its (Z)‐isomer 2 , 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐β‐D ‐galactopyranosyl‐(1→4)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐3‐O‐acetyl‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[β‐D ‐glucopyranosyl‐(1→3)]‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 3 ) and its (Z)‐isomer 4 , and 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐[O‐β‐D ‐galactopyranosyl‐(1→3)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐fucopyranosyl] ester ( 5 ) (presenegenin=(2β,3β,4α)‐2,3,27‐trihydroxyolean‐12‐ene‐23,28‐dioic acid).     

Cyclic voltammetry of nitrophenyl N‐glycosides on mercury electrode

Ten nitrophenyl N‐glycosides have been studied electrochemically in neutral (at pH 7) water–organic solutions by cyclic voltammetry using static mercury drop electrode. For all compounds under investigation the two electrochemical processes have been observed: the four‐electron irreversible reduction of their nitro groups to the corresponding phenylhydroxylamine derivatives, as well as the two‐electron quasi‐reversible process between phenylhydroxylamine and nitroso derivatives. For three compounds the additional electrochemical processes have been also observed, which can be connected with the formation of azoxybenzene derivatives. The potentials of both redox processes: a two‐electron quasi‐reversible R? NHOH/R? NO (E_f) and four‐electron irreversible R? NO₂/R? NHOH (E_pc(I)) systems have been determined and discussed according to crystal structures of selected compounds. E_f and E_pc(I) depended strongly on the positive mesomeric effect (caused by glycosidic nitrogen atom), as well as on the intramolecular hydrogen bond between electroactive nitro group and the hydrogen atom at the glycosidic atom observed in N‐o‐nitrophenyl‐2,3,4,6‐tetra‐O‐acetyl‐β‐D ‐glucopyranosylamine. Moreover, the chirality of selected reactants has had the pronounced effect on the E_pc(I). Copyright © 2011 John Wiley & Sons, Ltd.     

Fragmentation study of iridoid glycosides and phenylpropanoid glycosides in Radix Scrophulariae by rapid resolution liquid chromatography with diode‐array detection and electrospray ionization time‐of‐flight mass spectrometry

Rapid resolution liquid chromatography (RRLC) coupled with diode array detection (DAD) and electrospray ionization time‐of‐flight mass spectrometry (ESI‐TOF MS) method was applied to the mass spectral study of a series of naturally occurring iridoid glycosides and phenylpropanoid glycosides in Radix Scrophulariae, which provides higher speed and increased sensitivity without loss of resolution. With dynamic adjustment as the key role of the fragmentor voltage and confirmed with authentic standards, valuable structural information regarding the nature of both the glycoside skeletons was thus obtained. Most compositions were found to possess organic acid moiety such as cinnamoyl, caffeoyl and ferulyol. Besides extensive fragmentation of the carbohydrate moiety, losses of the hydroxyl and glucose residue units showed in the spectra, permitting the exploration of the skeleton and the identity of substituents in the molecule. Ten major iridoid glycosides and 10 phenylpropanoid glycosides were identified or tentatively characterized based on their retention times, UV and TOF MS data. The major fragmentation pathways of PGs in Radix Scrophulariae obtained through the MS data was schemed systematically for the first time, which provides a reference for other PGs derivatives. Copyright © 2009 John Wiley & Sons, Ltd.     

Two New Secoiridoid Glycosides from Tripterospermum chinense

Two new secoiridoid glycosides, tripterospermumcin A ( 1 ) and B ( 2 ), were isolated from the EtOH extract of the aerial parts of Tripterospermum chinense (Migo ) H. Smith , along with three known compounds, secologanin, secologanol, and sweroside. Their structures were established on the basis of UV, IR, MS, and extensive 1D‐ and 2D‐NMR analyses, as well as by literature comparison of spectroscopic data.