A cage-monoterpene indole alkaloid from Alstonia scholaris

An unprecedented cage-like alkaloid, scholarisine A was isolated from the leaves of Alstonia scholaris and its structure determined on the basis of 1D and 2D NMR, FTIR, UV, and high-resolution mass spectroscopic data. This alkaloid might be derived from picrinine via oxygenation, rearrangement, and lactonization.     

Alstobrogaline,an unusual pentacyclic monoterpenoid indole alkaloid with aldimine and aldimine-N-oxide moieties from Alstonia scholaris

Alstobrogaline (1), an unusual monoterpenoid indole alkaloid incorporating a third N atom and possessing two aldimine functions, with one being in the form of N-oxide, was isolated from the leaves of Alstonia scholaris. Its structure and relative configuration were determined by extensive NMR spectroscopic analysis, while its absolute configuration was established by X-ray diffraction analysis. A possible biogenetic pathway to 1 was proposed. Compound 1 displayed weak cytotoxic effects against MDA-MB-231 and MCF7 breast cancer cells.     

Iridoids from the Bark of Alstonia scholaris

Four new 11‐noriridoids named scholareins A–D ( 1 – 4 ), along with three known derivatives, isoboonein ( 5 ), alyxialactone ( 6 ), and loganin ( 7 ), were isolated from EtOH extracts of the bark of Alstonia scholaris by chromatographic methods. Their structures were identified by extensive mass‐spectrometric and spectroscopic (especially 2D‐NMR) experiments.     

Unique monoterpenoid indole alkaloids from Alstonia scholaris

[structure: see text] A pair of geometrically isomeric monoterpenoid indole alkaloids with a skeleton rearrangement and two additional carbons, named (19,20) E-alstoscholarine (1) and (19,20) Z-alstoscholarine (2), were obtained from the leaf extract of Alstonia scholaris. Their structures were elucidated on the basis of spectroscopic methods and then confirmed by X-ray crystal diffraction. The biogenesis of these compounds was also proposed.     

Meloslines A and B,two novel indole alkaloids from Alstonia scholaris

An unprecedented indole alkaloid melosline A (1), with 6/5/6/6 tetracyclic ring skeleton, together with a new alkaloid melosline B (2) and one known compound (3) were isolated from the leaves and twigs of Alstonia scholaris. The new structures were elucidated by comprehensive spectroscopic analysis. The absolute configuration of compound 1 was confirmed by comparison of experimental data with calculated electronic circular dichroism (ECD). Compound 1 exhibited moderate cytotoxicity against MCF-7 cancer cell lines.     

Three New Indole Alkaloids from the Leaves of Alstonia scholaris

Three new akuamillan‐type indole alkaloids, i.e., 5‐methoxystrictamine (=methyl (5β,16R,19E)‐5‐methoxyakuammilan‐17‐oate; 1 ), methyl (16R,19E)‐1,2‐dihydro‐16‐(hydroxymethyl)‐5‐oxoakuammilan‐17‐oate ( 2 ), and methyl (2β,16R,19E)‐4,5‐didehydro‐1,2‐dihydro‐2‐hydroxy‐16‐(hydroxymethyl)akuammilan‐4‐ium‐17‐oate chloride ( 3 ), have been isolated from the leaves of Alstonia scholaris, together with ten known compounds. Their structures were determined by spectroscopic means. None of the constituents showed significant cytotoxic activity towards WT cells.     

Alstonia scholaris: Struktur des Indolalkaloides Narelin

Alstonia scholaris: The structure of the indole alkaloid nareline Besides the known akuammidine, picralinal, picrinine and pseudoakuammigine a new indole alkaloid called nareline (M=352) was isolated from Alstonia scholaris R. BR. , which belongs to the plant family of Apocynaceae. Its structure 2 was deduced by single crystal X-ray diffraction. 2 represents the absolute configuration. The spectroscopic data of 2 and its derivatives (Scheme 1) as well as their chemical behavior support this structure. In biogenetic sense nareline is related to the bases akuammiline ( 4 ) and picraline ( 5 ) (Scheme 2). In contrast to those the C-atom 5 is exocyclic and represents an aldehyde group which forms together with the oxygen atom of the N (4)-hydroxylamine group a cyclic half acetale. - By oxidation (CrO₃/CH₃COOH) of 2 the oxindol derivative 19 (oxonareline) is formed which contains a cyclic acetal as a partial structure element (Scheme 4).     

A new type of monoterpenoid indole alkaloid precursor from Alstonia rostrata

Currently, all monoterpenoid indole alkaloids (MIAs) have been derived from strictosidine, which originates from the condensation of tryptophan with secologanin in a 1:1 ratio. However, our phytochemical research on Alstonia rostrata revealed a potential new precursor for these compounds. We isolated the alstrostines A and B, and it was determined that they were derived from tryptophan and secologanin in a 1:2 ratio, which supported the presence of a new type of MIA precursor.     

糖胶树叶挥发油化学成分研究

采用水蒸气蒸馏法提取糖胶树叶的挥发油.运用气质谱联用(GC-MS)技术研究海南糖胶树叶的挥发油化学成分.并采用峰面积归一化法确定各成分的相对质量分数.结果共鉴定出36种成分,占总离子流出峰面积的94.83%.糖胶树叶挥发油主要有α-蒎烯(16.62%),2-丙烯酸丁酯(15.86%)和大根香叶烯D(13.37%).本研究可为糖胶树的进一步研究开发和利用提供基础研究数据.     

The structure of angustifoline,an alkaloid ofLupinus angustifolius,in solution

Summary The¹H and¹³C NMR spectra of the lupin alkaloidangustifoline 1 in four solvents (cyclohexane-d₁₂, CDCl₃, CD₃CN, and C₆D₆) were assigned using 2D H,H and H,C COSY and 2D J-resolved spectra. The torsional HCCH angles calculated from the vicinalJ _HH coupling constants are essentially in agreement with those expected for the deformed all-chair conformation withendo oriented N(12)-H bond, reported earlier for1 in the solid state. Some arguments seem to point, however, to a small contribution of other conformations: with ring A deformed in another direction, deformed all-chair withexo oriented N(12)-H bond and/or a conformation with ring C in the boat form.Lupin Alkaloids, part 7     

Angustilodine,an Unusual Pentacyclic Indole Alkaloid from Alstonia

Two new indole alkaloids, angustilodine ( 1 ), with an unprecedented pentacyclic carbon skeleton, and angustilocine ( 2 ), belonging to the seco‐angustilobine‐B group of alkaloids, were obtained from the leaf extract of the Malayan species Alstonia angustiloba, and their structures were established by spectroscopic analysis.     

Structure of echitoserpine,a new alkaloid of the fruits of Alstonia venenata

Echitoserpine, a new 20-aroyloxy-16-methoxy vincadifformine alkaloid, has been isolated from the fruits of Alstonia venenata R.Br. and is shown to possess structure 1 on the basis of spectral and chemical evidence.     

The structure of delphinifoline,a diterpenoid alkaloid from aconitum delphinifolium

The structure of delphinifoline, a minor alkaloid of $\text{Aconitum}$$\text{delphinifolium}$ DC, was established by spectroscopic methods, and X-ray crystallography.     

Pharmacokinetic Analysis of Ursolic Acid in Alstonia scholaris R. Br. by High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - A simple and rapid high-performance thin-layer chromatographic method has been established and validated for determination of...     

Revised structure for fumarofine,an indenobenzazepine type alkaloid

Fumarofine is not a spirobenzylisoquinoline. Rather, it is the first know reduced indenobensazepine alkaloid, and possesses the cis B/C fused structure $\text{7}$. Rearrangement of synthetic spirobensylisoquinoline $\text{12}$ using methanesulfonyl chloride furnished indenobensazepine $\text{14}$. Osmium tetroxide oxidation of $\text{14}$ gave cis-glysol $\text{15}$. O-Methylfumarofine ($\text{8}$) was then obtained through pyridinium chlorochromate oxidation of $\text{15}$.