Na-formylechitamidine,an alkaloid from Alstonia boonei

A known alkaloid, echitamidine, and a new alkaloid, N_a-formylechitamidine, have been isolated from the stem bark of Alstonia boonei. The structure of this new alkaloid was assigned on the basis of chemical and spectroscopic data.     

(−)-3β-13α-dihydroxylupanine from cytisus scoparius

A new lupin alkaloid, (−)-3β,13α-dihydroxylupanine was isolated from Cytisus scoparius together with five known sparteine-type lupin alkaloids and tyramine. The absolute structure of the new alkaloid was confirmed by comparison of the natural product with the synthetic sample derived from (+)-13-hydroxylupanine. It was also shown that the alkaloid constituents of C. scoparius differed considerably in the aerial parts, flowers and seeds.     

(+)-11-oxocytisine,a lupin alkaloid from leaves of sophora secundiflora

A new lupin alkaloid, (+)-11-oxocytisine (1), was isolated from the leaves of Sophora secundiflora together with (−)-anagyrine, (−)-N-methylcytisine, (−)-baptifoline, (−)-N-formylcytisine, (−)-N-acetylcytisine and (−)-cytisine. The structure of the new alkaloid (1) was presumed to be (+)-11--oxocytisine on the basis of its spectroscopic data.     

Neopetrosiamine A,biologically active bis-piperidine alkaloid from the Caribbean sea sponge Neopetrosia proxima

A new tetracyclic bis-piperidine alkaloid, neopetrosiamine A (1), has been extracted from the marine sponge Neopetrosia proxima collected off the west coast of Puerto Rico. The structure of compound 1 was elucidated by analysis of spectroscopic data coupled with careful comparisons of its ¹H and ¹³C NMR data with those of a well-known 3-alkylbis-piperidine alkaloid model. The new alkaloid displayed strong in vitro cytotoxic activity against a panel of cancer cell lines as well as in vitro inhibitory activity against the pathogenic microbes Mycobacterium tuberculosis and Plasmodium falciparum.     

Indole alkaloids from Alstonia scholaris

A new indole alkaloid, alstonamine and a sitsirikine type indole alkaloid, rhazimanine, have been isolated from the leaves of Alstonia scholaris.     

3-dehydromitragynine: An alkaloid from Mitragyna speciosa

An investigation of the fresh leaves of Mitragyna speciosa has resulted in the isolation of a new alkaloid in addition to the indole alkaloids previously reported. The new alkaloid is the 3-dehydro derivative of mitragynine and its structure was elucidated by spectral means and chemical transformations. (-)-Epicatechin was also isolated from the leaves.     

Pachyovatamine,a bisbenzylisoquinoline alkaloid,and other alkaloids from Pachygone ovata

A new dibenzo-p-dioxin biphenyl bisbenzylisoquinoline alkaloid, pachyovatamine, has been isolated from an extract of the leaves and stems of Pachygone ovata from Sri Lanka. The alkaloid was characterized by a consideration of its physicochemical data and conversion to O-acetyltiliacorinine. Pachygonamine, N-methylpachygonamine and tiliamosine were also isolated from the same extract.     

19-hydroxycoronaridin und 19-hydroxyibogamin,zwei antibiotisch wirksame alkaloide vom ibogamin-typ

During the separation of an extract from Tabernaemontana glandulosa, small amounts of a new alkaloid were obtained for which the structure 19-hydroxycoronaridine was deduced. This new alkaloid and 19-hydroxyibogamine, which can be obtained from it, show marked antibiotic activity in the agar plate diffusion test.     

An aporphinoid alkaloid from Pseuduvaria macrophylla

Chromatographic separation of the alkaloid fraction of the methanol extract from the stem bark of Pseuduvaria macrophylla resulted in the isolation of a new aporphinoid alkaloid, 1,2,3-trimethoxy-4,5-dioxo-6a,7-dehydroaporphine, together with possibly the known O-methylmoschatoline.     

Nummularine-O,a cyclopeptide alkaloid from Zizyphus nummularia

In addition to the known peptide alkaloid jubanine-B, a new peptide alkaloid, nummularine-O, has been isolated from the stem bark of Zizyphus nummularia and their structures have been elucidated by chemical and spectroscopic methods.     

Alkaloids of some south american erythroxylum species

Fourteen South American species of Erythroxylum representing four sections of the genus were examined for tropane and related alkaloids. The alkaloid content of the dried material ranged from 0.002 to 0.20 %. Commonly, the alkaloids involved were esters of various tropanols with benzoic and phenylacetic acids. A new alkaloid, nortropacocaine, was isolated from E. mamacoca. Mass spectrometry indicated the existence of other new bases, cuscohygrine and, in some species dihydrocuscohygrine. Chemotaxonomic implications are discussed.     

Alkaloids,coumarins and flavonoids of Micromelum zeylanicum

The leaves and stems of Micromelum zeylanicum have yielded a new oxazole alkaloid, O-methylhalfordinol, the coumarin micromelin and a flavone, 5-hydroxy-3,3′,4′,7,8-pentamethoxyflavone. In addition, the stems contained 6-formyl-7-methoxycoumarin, and the leaves contained the carbazole alkaloid koenigine and β-sitosterol. Chemical and spectral evidence are presented to support the proposed structures.     

A new alkaloid from south african Conium species

Recent screening of South African Conium species for alkaloids as part of taxonomic studies has yielded γ-coniceine, coniine, methylconiine, conhydrine and a new alkaloid N-methylpseudoconhydrine. The relative stereochemistry of N-methylpseudoconhydrine was ascertained by ¹H NMR decoupling experiments. This latter alkaloid was found in significant amounts in the leaf and stem of some plants investigated and was the major alkaloid along with conhydrine in the leaf and stem of one group of high altitude plants. These plants also contained significant amounts of volatile oil, the major monoterpene being myrcene.     

Isolation of the pyrrolizidine alkaloid 1-epialexine from Castanospermum australe

The Australian leguminous tree Castanospermum australe contains the anti-viral glucose analogue indolizidine alkaloid castanospermine. As the result of a search for new bioactive carbohydrate-like compounds we now report the isolation of the novel polyhydroxylated pyrrolizidine alkaloid, 1-epialexine, from the leaves and stems of C. australe. 1-Epialexine is a weak inhibitor of β-mannosidase from Cellullomonas fimi.     

Structure of erysophorine: a new quaternary alkaloid of Erythrina arborescens

Isolation and structure elucidation of a new quaternary indole-eryso alkaloid, named erysophorine, from seeds of Erythrina arborescens are reported. An indole-erythrina alkaloid, such as erysophorine, has not been encountered before in nature or prepared synthetically.     

Rotundifoline N-oxides

The N-oxides of rotundifoline are prepared for comparison with a new alkaloid from Mitragyna rubrostipulata.     

Alkaloids of Bolusanthus speciosus

Investigation of the alkaloids of Bolusanthus speciosus afforded a new quinolizidine alkaloid, 6β-hydroxylupanine. The structure of this alkaloid was assigned on the basis of spectroscopic methods and by chemical transformations. The other alkaloids isolated were cytisine, N-methylcytisine, 11α-allylcytisine, anagyrine, 13-hydroxyanagyrine, 5,6-dehydrolupanine, lupanine, sparteine and β-isoparteine. The biosynthetic significance of these findings is discussed briefly.     

Lupin alkaloids from sophora chrysophylla

A new lupin alkaloid, (?)-mamanine N-oxide, was isolated from Sophora chrysophylla together with 18 known alkaloids including some unusual lupin alkaloids such as kuraramine, lamprolobine, epilamprolobine, epilamprolobine N-oxide, (+)-mamanine and (?)-pohakuline. It was also shown that the alkaloid constituents of S. chrysophylla differed considerably in the leaves, stems and seeds.     

N-Formylcytisine: A new alkaloid from Thermopsis chinensis

A new base have been isolated from Thermopsis chinensis along with N-methylcytisine, cytisine, anagyrine and lupanine. The new alkaloid have been shown to be N-formylcytisine.     

Alkaloids of Haemanthus kalbreyeri

The roots of Haemanthus kalbreyeri contain a new phenanthridone alkaloid, kalbretorine, and a new glucosyloxy alkaloid, kalbreclasine. Additionally, six known alkaloids, viz. haemanthamine, haemanthidine, hippadine, lycorine, narciclasine and pratorimine, previously reported from other Amaryllidaceous plants have now been isolated also from this species. Kalbretorine produced marked inhibition of growth and viability of S-180 tumour cells. Kalbreclasine caused significant mitogenic activation of splenic lymphocytes characteristic of immuno stimulants.