Two new alkaloids from Crinum asiaticum var. sinicum

Two new alkaloids (1, 2) were isolated from the whole plants of Crinum asiaticum var. sinicum together with seven known alkaloids. The structures of the new alkaloids were elucidated by spectroscopic analyses and chemical conversions from known alkaloids. New alkaloid 1 was isolated for the first time as a natural product, although it has been prepared as a synthetic product.     

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 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.     

Norditerpenoid alkaloids from the processed tubers of Aconitum carmichaeli

Four new and five known norditerpenoid alkaloids were isolated from the processed tubers of Aconitum carmichaeli. The new alkaloids are 14-O-cinnamoylneoline (3), 14-O-anisoylneoline (4) 14-O-veratroylneoline (5), and lipo-14-O-anisoylbikhaconine (8). The known alkaloids are neoline (1), 14-O-acetylneoline (2), foresaconitine (6), crassicauline A (7), and lipohypaconitine (9). Alkaloids 2, 6, and 7 were isolated from this plant for the first time. The structures of the new alkaloids were established by spectroscopic and chemical methods.     

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     

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.     

Two new monoterpenoid indole alkaloids from Tabernaemontana divaricata

Two new monoterpenoid indole alkaloids, tabervarines A (1) and B (2), along with seven known monoterpenoid indole alkaloids, were isolated from the methanol extract of the twigs and leaves of Tabernaemontana divaricata. The structures including the absolute configurations of the new alkaloids were elucidated based on MS, NMR, and ECD calculation. The in vitro cytotoxic activities of the isolated alkaloids against several human cancer cell lines were also evaluated.     

New bisindole alkaloids isolated from Myxomycetes Arcyria cinerea and Lycogala epidendrum

Two new bisindole alkaloids, named cinereapyrrole A (1) and B (2), were isolated from wild fruit bodies of Arcyria cinerea and three new bisindole alkaloids (3-5) were isolated from wild fruit bodies of Lycogala epidendrum. Seven known bisindoles (6-12) were concomitantly obtained from them. The structures of the new compounds were elucidated by spectral data. Among these bisindole alkaloids, compound 12 showed cytotoxicity against cultured tumor cell lines.     

New pavine N-oxide alkaloids from the stem bark of Cryptocarya chinensis Hemsl

Three new pavine N-oxide alkaloids, (-)-isocaryachine-N-oxide B, (+)-caryachine-N-oxide, (-)-caryachine-N-oxide, and a new isoquinoline alkaloid, 6,7-methylenedioxy-N-methylisoquinoline together with 11 known alkaloids were isolated and characterized from the stem bark of Cryptocarya chinensis. The structures of the isolated compounds were determined by spectral methods. The stereochemistry of pavine-N-oxide alkaloids is also discussed.     

New bisbenzylisoquinoline alkaloids from Cocculus laurifolius

Two new bisbenzylisoquinoline alkaloids, alpha, alpha'-dioxo-7'-O-demethylstebisimine (1) and 7'-O-demethylstebisimine (2), along with 14 known alkaloids, were isolated from the roots of Cocculus laurifolius. These alkaloids were characterized mainly by spectroscopic methods.     

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.     

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.     

Alkaloids from the stem bark of Turraeanthus africanus (Meliaceae)

Fractionation of the methanol extract of the stem bark of Turraeanthus africanus led to the isolation of two new alkaloids designated turraeanthin A and B, together with two known alkaloids. The structures of the new alkaloids were elucidated by means of spectroscopic analysis and characterized as 10-O-demethyl-17-O-methyl isoarnottianamide and 11-demethoxyl-12-methoxyl oxynitidine respectively.     

喜树中的吲哚生物碱

从喜树(Camptetheca acuminata Decne)果中分到五个微量吲哚类生物碱, 其中两个为新生物碱, 分别为camptacumotint(1)和camptacumanine(2), 另外三个为已知生物碱naucleficine(3), angustoline(4)和新天然产物二氢异喹胺(dihydroisoquinamine, 5).     

Two New Indole Alkaloids from Emmenopterys henryi

Two new indole alkaloids, 5‐oxodolichantoside ( 1 ) and deglycocadambine ( 2 ), were isolated from the twigs and leaves of Emmenopterys henryi, together with four known indole alkaloids and five known iridoids. The structures of the new compounds were elucidated on the basis of extensive spectroscopic analyses, including 1D‐ and 2D‐NMR experiments, and confirmed by single‐crystal X‐ray diffraction studies. This is the first report on the isolation of indole alkaloids from this species. The indole alkaloids were evaluated for their cytotoxic activities against five human cancer lines.     

Erythrinan alkaloids from seeds of Erythrina velutina

Four new Erythrinan alkaloids (1-4) were isolated from the seeds of Erythrina velutina. The structures of these new compounds 1-4 were elucidated by spectroscopic methods including 2D-NMR. Three of four were found to be novel sulfated Erythrinan alkaloids.     

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.     

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.     

New C19-diterpenoid alkaloids from Aconitum piepunense

Two new C(19)-diterpenoid alkaloids, piepunensine A (1) and 18-acetylcammaconine (2), have been isolated from the roots of Aconitum piepunense together with five known alkaloids pengshenine B (3), talatisamine (4), aconosine (5), yunaconitine (6), and talatizidine (7). The structures of the new alkaloids were established on the basis of spectral data (1D- and 2D-NMR, HR-MS).     

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.