Alcaloides des feuilles du Crioceras dipladeniiflorus

Three alkaloids have been isolated from leaves of Crioceras dipladeniiflorus. Two of them, 12-methoxy-voaphylline and criophylline are new and their structures have been determined. The third has been identified as andrangine an alkaloid isolated recently from another Apocynaceae Craspidospermum verticillatum.     

Lupin alkaloids from flowers of Echinosophora koreensis

(?)-Methyl 12-cytisineacetate (2) was isolated from methanol extracts of fresh flowers of Echinosophora koreensis together with seven known lupin alkaloids. Ethyl 12-cytisineacetate (3) was also isolated from ethanol extracts of the same flowers. Compounds 2 and 3 were artifacts and (?)-12-cytisineacetic acid (4) is assumed to be the principal source of 2 and 3. The variations in alkaloid content during growth of the flowers and the seedlings were also examined.     

Leaf alkaloids of Rauwolfia vomitoria

Nineteen indole alkaloids were isolated from Ghanaian Rauwolfia vomitoria leaves. The alkaloids comprised E-seco indole, sarpagan, picrinine, akuammiline, heteroyohimbine, oxindole, yohimbine and indolenine types. The biosynthetic relationship of the alkaloids is discussed.     

Desmethoxyabresoline and 10-epi-desmethoxyabresoline,new ester alkaloids in Heimia salicifolia

Two new ester alkaloids, desmethoxyabresoline and 10-epi-desmethoxyabresoline, have been isolated from young seedlings of Heimia salicifolia and have been synthesized. Chemical and physical properties of the natural and synthetic isomers are in agreement. The presence of these alkaloids adds support to the postulate that the biphenyl system of the lythraceous alkaloids is derived from trans-cinnamate esters of phenylquinolizidinols.     

Alkaloids of Rauwolfia cumminsii stem

24 indole alkaloids were isolated from the stem bark of Rauwolfia cumminsii and 21 identified. The alkaloids comprised E-seco, sarpagan, dihydroindole, yohimbine, heteroyohimbine, 18-hydroxyyohimbine ester and anhydronium types together with peraksine and deacetylpicraline. The probable biosynthesis of the alkaloids is discussed.     

Stem alkaloids of Rauwolfia vomitoria

22 indole alkaloids were isolated from the stem bark of Nigerian Rauwolfia vomitoria and 20 characterized. The alkaloids comprised E-seco heteroyohimbine, sarpagan, dihydroindole, yohimbine and heteroyohimbine types. The biosynthetic relationship of the alkaloids is discussed.     

Alkaloids of Thermopsis Lupinoides

Ammodendrine, together with seven other known lupin alkaloids, was isolated from Thermopsis lupinoides. (+)-Lupanine (+)-17-oxolupanine occurred together with (?)anagyrine, (?)-baptifoline, (?)-cytisine, (?)-N-methylcytisine (?)N-formylcytisine. These alkaloids have the opposite stereochemistry to that of (+)-lupanine and (+)-17-oxolupanine. The distribution of alkaloids in fresh flowers, leaves, stems roots of this plant was also examined.     

New alkaloids from Strychnos icaja

The alkaloids of Strychnos icaja (Loganiaceae) have been studied. An extract from Zaire leaf material yielded nine alkaloids, comprising novacine, the new base 21,22-α-epoxy-4,14-dihydroxy-3-methoxy-N-methyl-sec.-pseudostrychnine, and seven others of known structure previously obtained from the plant. Cameroun leaf material gave five alkaloids, of which one, 21,22-α-epoxy-3,4-dimethoxy-N-methyl-sec.-pseudostrychnine, is new. Fruits from Gabon afforded eight alkaloids; two of them are new and are formulated as 21,22-α-epoxy-4-methoxy-N-methyl-sec.-pseudostrychnine and the corresponding 14-hydroxy derivative.     

Alkaloids of stem and rootbark of Tabernaemontana dichotoma

During chemical investigation for compounds possessing biological activity in the stem and rootbark of Tabernaemontana dichotoma, 22 alkaloids were isolated. Ten monomeric alkaloids were identified, viz. (?)-apparicine, coronaridine, 3-oxocoronaridine, 3-ketopropylcoronaridine, 19R-heyneanine, 3-ketopropyl-19R-heyneanine, ibogamine, isomethuenine, perivine and vobasine. Two of the monomeric alkaloids isolated were new, one was identified as 3,19R-oxidocoronaridine and the other one is not yet identified. The other ten alkaloids isolated were dimeric compounds, three were identified as tabernamine, voacamine and 3′R/S-hydroxyvoacamine. Five of the dimers were new alkaloids related to tabernamine and ervahanine type structures and identified as 3′R/S-hydroxytabernamine, 3′R/S-hydroxy-N₄-demethyltabernamine, N₄-demethyltabernamine and 3′R/S-hydroxy-N₄-demethytervahanine A and B. The remaining two alkaloids are partially characterized.     

Leaf alkaloids of Rauwolfia volkensii

Thirteen alkaloids were isolated and identified from the leaves of Rauwolfia volkensii. The alkaloids included E-seco heteroyohimbine, heteroyohimbine, sarpagan, dihydroindole, pleiocarpamine, picrinine and akuammicine types together with peraksine.     

Alkaloids of turkish papaver tauricola

The major alkaloids of Papaver tauricola collected in three different parts of Anatolia have proved to be of the rhoeadine type. The three collections possessed different major alkaloids and the existence of chemical strains containing rhoeadine-type alkaloids, is indicated. In addition to the rhoeadine-type alkaloids (rhoeagenine, rhoeadine, oreogenine, oreodine, glaucamine, glaudine and epiglaudine), tetrahydroprotoberberine-(sinactine, scoulerine) and isopavine- (amurensinine) type alkaloids have been isolated as minor products. These findings contrast with the previous literature in which 1-benzyltetrahydroisoquinoline- and proaporphine types were reported to be the major alkaloids.     

Alkaloids of Lycopodium magellanicum

Six alkaloids have been isolated from Lycopodium magellanicum. These include the known alkaloids lycopodine, acetyldihydrolycopodine, lycodine, N-methyllycodine, acetylfawcettine and a new alkaloid, 5-dehydro-magellanine. The chemical correlation of magellanine and paniculatine and the establishment of their absolute configuration are described.     

Alkaloids in the venom of Messor ants

Tobacco alkaloids of the anabasine type have been found or confirmed in the venom of five species of arid-dwelling Messor ants. They are frequently accompanied by alkylpyrazines. Messor mediorubra contains four alkaloids, with anabasine the major component and also minor pyrazines. Anabasine was found alone in the venom of Messor semirufus and confirmed in Messor ebeninus. Messor rugosus from Tel Aviv contained a mixture of alkaloids and pyrazines, but those from Ein Yahav contained 3-ethyl-2,5-dimethylpyrazine, some 2-phenylethylamine, and N-ethylidene 2-phenylethylamine. Messor arenarius is confirmed as having a complex but variable mixture of alkaloids and pyrazines.     

Stem alkaloids of Rauwolfia obscura

The indole alkaloids alstonine, 10-methoxygeissoschizol, tetrahydroalstonine, vomalidine, α-yohimbine and 19, 20-dehydroyohimbine, an unidentified anhydronium-like base and choline were isolated from Rauwolfia obscura stems. The diester alkaloids reserpine and rescinnamine, which occur in the roots, were not detected. The origin and inter-relationship of the detected alkaloids are discussed.     

Leaf alkaloids of Rauwolfia oreogiton

Twenty-one indole alkaloids were isolated from the leaves of Rauwolfia oreogiton and identified. The alkaloids comprised E-seco heteroyohimbine, heteroyohimbine, akuammiline, akuammicine, pleiocarpamine, picraline, picrinine, dihydroindole and sarpagan types. No chemical differentiation between the leaves of R. oreogiton and R. volkensii could be established.     

La 12′-hydroxyisostrychnobiline: Nouvel alcaloïde du Strychnos variabilis

The structure of a new bisindole alkaloid, 12′-hydroxyisostrychnobiline, has been proposed from the analysis of its 300 MHz ¹H NMR spectrum and comparison of the spectroscopic data with those of various monomeric and dimeric alkaloids, previously isolated from the same Strychnos species     

Alkaloid catabolism and mobilization in catharanthus roseus

The catabolic turnover of vindoline and catharanthine, indole-dihydroindole alkaloids produced by Catharanthus roseus, occurs much more rapidly in apical cuttings than in intact plants. The implication of the results is that such alkaloids may participate actively in the plant's biochemical processes under certain conditions, in contradistinction to the general belief that plant alkaloids are metabolically insignificant.     

The sequential appearance and metabolism of alkaloids in Heimia salicifolia

The seeds of Heimia salicifolia do not contain alkaloids. Two unidentified alkaloids were detected in 1-week-old seedlings; these alkaloids were absent from older plant samples. Lyfoline, cryogenine, and lythrine were first detected in 2-week-old plants. Sinicuichine was first observed in 3-week-old plants and nesodine in 2-month-old plants. The maximum rates of synthesis for most of these alkaloids occurred in 1- to 2-month-old plants. Following administration of ¹⁴CO₂ to H. salicifolia plants, small quantities of alkaloids were purified to constant specific activity without alkaloid dilution; 95.6% of the administered ¹⁴CO₂ was assimilated and up to 0.16% of this activity was incorporated into known alkaloids. Sinicuichine and lyfoline were shown to undergo catabolism, while cryogenine was degraded very slowly, if at all. Evidence is presented for the conversion of lyfoline to lythrine.     

Distribution of alkaloids in Anthocercis littorea and A. viscosa

The distribution of tropane alkaloids in organs of Anthocercis littorea and A. viscosa is reported. The following alkaloids have been isolated: atropine (hyoscyamine), apoatropine, noratropine (norhyoscyamine), littorine, hyoscine, norhyoscine, meteloidine, 3α, 6β-ditigloyloxytropan-7β-ol, 6β-tigloyloxytropan-3α-ol, 3α-tigloyloxytropane, tigloidine, tropine, ψ-tropine, (?)-tropan-3α-6β-diol, cuscohygrine and unknown bases.     

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.