Seven New Monoterpenoid Indole Alkaloids from Gelsemium elegans

Seven new indole alkaloids were isolated from the roots of Gelsemium elegans Benth. and their structures were determined by spectroscopic analysis and chemical transformation from known alkaloids. Kounaminal ( 1 ) is a new koumine‐type alkaloid that contains an unusual aminal moiety. Humantenoxenine ( 2 ) and 15‐hydroxyhumantenoxenine ( 3 ) are humantenine‐type alkaloids that contain a novel β‐amino‐α,β‐unsaturated ketone residue. The other four novel alkaloids are two gelsedilam‐related and two gelsenicine‐related alkaloids.     

Alkaloids of Aconitum tuberosum. Structure of Tuberaconitine and Tubermesaconitine

Total alkaloids ofAconitum tuberosumroots afforded neoline and two new alkaloids, tuberaconitine and tubermesaconitine. The structures of the new alkaloids were proved based on spectral data and chemical transformations from aconitine and mesaconitine     

Three new C_(20)-diterpenoid alkaloids from Delphinium anthriscifolium var.savatieri

Three new C20-diterpenoid alkaloids, designated as anthriscifolmines A-C (1-3), together with two known alkaloids denudatine and delgramine, were isolated from the whole herb of Delphinium anthriscifolium var. savatieri. The structures of these new alkaloids were elucidated on the basis of spectral data.     

Alkaloids from Fruits of Daphniphyllum oldhamii

Seventeen Daphniphyllum alkaloids, including two new pentacyclic alkaloids, yuzuric acid ( 1 ) and daphnezomic acid ( 2 ), and 15 known ones, were isolated from the fruits of Daphniphyllum oldhamii. The structures and configuration of the two new alkaloids were determined on the basis of spectroscopic methods, especially 2D NMR techniques.     

Rauniticine-allo-oxindole B and rauniticinic-allo acid B, new heteroyohimbine-type oxindole alkaloids from the stems of Malaysian Uncaria longiflora var. pteropoda

Two new heteroyohimbine-type oxindole alkaloids, rauniticine-allo-oxindole B and rauniticinic-allo acid B, have been successfully isolated from the stems extract of Malaysian Uncaria longiflora var. pteropoda. The structures of the two new alkaloids were determined by spectroscopic analysis.     

pH‐Zone‐refining counter‐current chromatography for two new lipo‐alkaloids separated from refined alkaline extraction of Kusnezoff monkshood root

An efficient and refined method for the separation of six aconitine‐type alkaloids from the alkaline prepared “Kusnezoff monkshood root” was established. It is the first study that two new lipo‐alkaloids were successfully isolated from refined sample by pH‐zone‐refining counter‐current chromatography rather than synthetic method. It was of interest that a great deal of lipo‐alkaloids was produced in crude extract from the alkalization of “Kusnezoff monkshood root.” A refined sample method was proposed to enrich two types of alkaloids by liquid–liquid extraction, i.e. lipo‐alkaloids and monoester‐diterpenoid alkaloids. The pH‐zone‐refining counter‐current chromatography was performed with an optimized two‐phase solvent system composed of n‐hexane‐ethyl acetate–methanol–water (3:5:4:5, v/v), where upper organic phase was added to 3 mmol/L triethylamine as a retainer and lower aqueous mobile phase was added to 3 mmol/L hydrochloric acid as an eluter. As a result, six aconitum alkaloids, including two lipo‐alkaloids (8‐lino‐14‐benzoylaconine, 8‐pal‐14‐benzoylaconine), three monoester‐diterpenoid alkaloids (14‐benzoylmesaconine, 14‐benzoylaconine, beyzoyldeoxyaconine), and one aconine alkaloid (neoline) were acquired from the plant at the same time. The anti‐inflammatory activities of the two new lipo‐alkaloids were compared to the six alkaloids in vitro, in cyclo‐oxygen‐ase‐2 inhibition assays. The separation mechanism of six alkaloids by pH‐zone‐refining counter‐current chromatography was illustrated.     

New cholinesterase inhibiting bisbenzylisoquinoline alkaloids from Cocculus pendulus

Phytochemical investigation on Cocculus pendulus (J. R. & G. FORST.) resulted in the isolation of two new and three known bisbenzylisoquinoline alkaloids. The structures of the new alkaloids, kurramine-2'-beta-N-oxide (1) and kurramine-2'-alpha-N-oxide (2), were elucidated with the help of spectroscopic techniques. The cholinesterase inhibitory activities of these bisbenzylisoquinoline alkaloids are reported here for the first time.     

Diterpenoid Alkaloids from Delphinium tatsienense

Three new C₂₀‐diterpenoid alkaloids, along with twenty‐two known alkaloids, were isolated from the whole herbs of Delphinium tatsienense. The new alkaloids include a vakognavine‐type C₂₀‐diterpenoid alkaloid, designated as tatsienenseine A ( 1 ), and two hetisine‐type C₂₀‐diterpenoid alkaloids, designated as tatsienenseines B ( 2 ) and C ( 3 ). Their structures were elucidated by IR, HR‐ESI‐MS, 1D‐ and 2D‐NMR analyses.     

虎皮楠生物碱研究进展

虎皮楠生物碱结构多变且具有复杂的多环骨架, 该类生物碱奇特的多环结构使其成为化学和生物合成研究的热点之一. 最近的关于虎皮楠生物碱的综述是由Kobayashi和Morita等于2003年报道的, 文章对1987到2002年间虎皮楠生物碱的研究进行了概括. 其后又有从11种虎皮楠植物中分离到的60多个新的虎皮楠生物碱报道, 其中三分之二是由中国学者从分布于中国的虎皮楠植物中分离得到. 这些新生物碱有的骨架类型已知, 有的骨架新颖. 故对这些新生物碱的结构分类、可能的生物合成途径和生物活性进行了综述. 对生物碱的分类基本按照以前提出的方法, 但增加了7种新的骨架类型. 对各种骨架的结构特点及在生物合成中的相互关系也进行了讨论.     

Alkaloids of Tabernaemontana eglandulosa

From the leaves and twigs of Tabernaemontana eglandulosa 22 alkaloids, of which 12 are new, have been isolated. Besides tacamine (pseudo-vincamine) 7 other alkaloids of this new class of indole alkaloids were identified. A further three alkaloids of the cleavamine type, namely the known ( + )20R-15, 20-dihydro-cleavamine and (-)20S-15, 20-dihydro-cleavamine and one new alkaloid, which was tentatively identified as 14S, 20R-velbanamine, two new alkaloids of the pseudo-aspidospermidine type, namely 20R-l,2-dehydro-pseudo-aspidospermidine and 20S-hydroxy-l,2-dehydro-pseudoaspidospermidine and an alkaloid of a novel iboga type were isolated. More common alkaloids isolated were coronaridine, 11-hydroxycoronaridine, voaphylline, tubotaiwine, ibogamine, norfluorocurarine and probably a mixture of 20R- and 20S-pseudo-vincadifformine. Only quantitative differences in the alkaloid content of the leaves, twigs and stembark were observed.     

Diterpenoid Alkaloids from Delphinium yunnanense

Three new diterpenoid alkaloids, along with eleven known alkaloids, were isolated from the whole herbs of Delphinium yunnanense. The new alkaloids include a rearranged‐type C₁₉‐diterpenoid alkaloid, named yunnanenseine A ( 1 ), and two hetisine‐type C₂₀‐diterpenoid alkaloids, named yunnanenseine B and C ( 2 and 3 , resp.). Their structures were elucidated by detailed NMR‐spectroscopic studies.     

Chemical constituents of Taraxacum formosanum

Three new compounds, taraxacine-A (1), taraxacine-B (2) and taraxafolin (3) together with twenty-five known compounds, which include two beta-carboline alkaloids, two indole alkaloids, two chlorophylls, two flavonoids, one coumarin, two triterpenoids, one monoterpenoid, one ionone, four steroids and eight benzenoids, were isolated and characterized from the fresh aerial parts of Taraxacum formosanum. Structures of new compounds were determined by spectral analysis.     

Some new mitragyna-type indoles and oxindoles; The influence of stereochemistry on mass spectra

The indole alkaloids corynantheidine and paynantheine have been epimerized to two new compounds and corynantheidine and mitragynine have been transformed to the corresponding oxindoles. The stereochemistry of the new compounds is deduced from physical data. Mass spectral fragmentation of the mitragyna indole and oxindole alkaloids is discussed with reference to their stereochemistry.     

New C(19)-diterpenoid alkaloids from the roots of Delphinium potaninii var. jiufengshanense

From the roots of Delphinium potaninii var. jiufengshanense, two new lycoctonine-type C(19)-diterpenoid alkaloids called jiufengdine (1) and jiufengtine (4) have been isolated. The structures of the new alkaloids (1, 4) were established by 1D and 2D NMR spectra.     

Erythrina alkaloids from leaves of Erythrina arborescens

Continued interest in Erythrina alkaloids resulted in the isolation of 38 alkaloids including 7 undescribed ones from the leaves of Erythrina arborescens Roxburgh. Among the new compounds, erythrivarines H-I were two dimeric alkaloids, while others were Erythrina alkaloid glucosides. Dimeric Erythrina alkaloids and monomers, turcomanidine and isoboldine, showed medium xanthine oxidase inhibition.     

Indole alkaloids from Vinca major and V. minor growing in Turkey

A new indole alkaloid, 11-hydroxypolyneuridine, was isolated from Vinca major subsp. major L. and the known indole alkaloids vallesiachotamine and isovallesiachotamine from Vinca minor L. This is the first report on the alkaloids of both Vinca species growing in Turkey; vallesiachotamine and isovallesiachotamine were isolated from a Vinca species for the first time. V. minor may be considered as a new source for these two alkaloids due to their occurrence in high amount in the aerial parts of the plant. The alkaloid extracts of the two Vinca species were found to have high lipid peroxidation inhibitory and DPPH radical scavenging activities. Anticholinesterase activity of the extracts was also very strong.     

Two new C18-norditerpenoid alkaloids from Aconitum delavayi

Further phytochemical investigation of the unique C18-norditerpenoid alkaloids from the roots of Aconitum delavayi Franch ledto the isolation of two new norditerpenoid alkaloids,delavaconitine F 1 and delavaconitine G 2.Their structures were determinedfrom spectroscopic evidence.     

Three new diterpenoid alkaloids from roots of Aconitum ouvrardianum HAND.-MAZZ

A new C(19)-diterpenoid alkaloid, ouvrardiantine (1) and two new C(20)-diterpenoid alkaloids, ouvrardiandines A (2) and B (3) were isolated from the root of Aconitum ouvrardianum HAND.-MAZZ. The structure of the new alkaloids was established on the basis of spectral data (1D- and 2D-NMR, HR-MS).     

Alkaloids ofColchicum luteum

The paper gives a review of the alkaloids ofColchium luteum Baker from various growth sites. The structure of luteidine — one of the main alkaloids of the plant — has been established. In addition, two new alkaloids have been isolated from the plant and the structure of one of them has been established as collutine N-oxide.     

Synthesis, structure and stereochemistry of quinoline alkaloids from Choisya ternata

A range of seventeen quinoline alkaloids, involving several types of oxidations during their biosynthetic pathways, have been isolated from leaves of Choisya ternata. In addition to the nine known quinoline alkaloids, eight new members of the furoquinoline family, derived mainly from prenylation at C-5 (including two novel hydroperoxides), have been identified. The absolute configurations and enantiopurity values of all chiral quinoline alkaloids have been determined. One of the isolated alkaloids, 7-isopentenyloxy-gamma-fagarine, has been used as a precursor for the chemical asymmetric synthesis of the enantiopure alkaloids: evoxine, anhydroevoxine and evodine. The possible roles of oxygenase and other oxygen-atom-transfer enzymes, in the biosynthetic pathways of the C. ternata alkaloids, have been discussed.