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.     

Alcaloïdes d'Alstonia quaternata

Eleven alkaloids have been isolated from Alstonia quaternata. Three of them, namely 11-methoxy-epi-3α-yohimbine, 10,11-dimethoxy-picrinine designated quaternine, and 19,20-epoxy-N_(a)-methyl, desacetyl, desformo, 2βH-dihydroakuammiline designated quaternoxine, are new alkaloids.     

Sesquiterpenes and alkaloids from Cleistopholis patens

The root bark of Cleistopholis patens collected in Ghana yielded two sesquiterpenes and five alkaloids. The sesquiterpenes have been characterised as the acyclic methyl-(?)-(trans)-(trans)-10,11-dihydroxyfarnesoate and its monocyclic derivative methyl-(+)-10-hydroxy-6,11-cyclofarnes-7(14)-enoate. The alkaloids were of the unusual aza-polycyclic and naphthyridine groups and included one new member of both classes. Examination of stem bark samples from the same source and from Sierre Leone showed the presence of the sesquiterpenes and the oxoaporphine alkaloid liriodenine but neither of the rarer alkaloid types.     

Additional alkaloids from Laurelia philippiana and L. novae-zelandiae

Asimilobine, anonaine, noreorydine, nornantenine, (+)-reticuline and the new alkaloid, 4-hydroxyanonaine, were isolated from Laurelia philippiana bark. The biogenetically related obovanine, oxoputerine and (?)-romneine, not known as a natural product, were obtained from the bark of L. novae-zelandiae. The occurrence of (R)-norlaudanosoline-derived alkaloids in L. novae-zelandiae is a distinctive feature of this tree. Neither L. novae-zelandiae nor L. philippiana accumulate dimeric benzylisoquinoline alkaloids to any appreciable extent in the trunk bark, differing in this respect from L. sempervirens, the only other Laurelia species.     

(−)-Epilamprolobine and its N-oxide,lupin alkaloids from Sophora tomentosa

From the fresh leaves of Sophora tomentosa, three new lupin alkaloids, (?)-epilamprolobine, (+)-epilamprolobine N-oxide and 5-(3′-methoxycarbonylbutyroyl)aminomethyl-trans-quinolizidine N-oxide, have further been isolated along with (+)-matrine, (+)-matrine N-oxide, (+)-sophocarpine N-oxide, (?)-anagyrine, (?)- baptifoline, (?)-cytisine, (?)-N-methylcytisine, (?)-N-formylcytisine, (?)-N-acetylcytisine and (±)-ammodendrine. The absolute configurations of (+)-epilamprolobine N-oxide (1R:5R:6S) and (?)-epilamprolobine (5R:6S) have also been established by spectroscopic data and by comparison with synthetic (+)-epilamprolobine (5S:6R)derived from (?)-lupinine (5R:6R). (?)-Epilamprolobine is a diastereomer of (+)-lamprolobine (5R:6R) in Lamprolobium fruticosum and 5-(3′-methoxycarbonylbutyroyl) aminomethyl-trans-quinolizidine N-oxide is presumed to be an artefact. A biosynthetic pathway for the formation of (?)-epilamprolobine is also proposed.     

Alkaloids from trunk bark of Hernandia nymphaeifolia

Six new alkaloids, (+)-ovigerdimerine, 4-methoxyoxohernandaline, 7-formyldehydrohernangerine, 5,6-dimethoxy-N-methylphthalimide, 7-hydroxy-6-methoxy-1-methylisoquinoline and (+)-vateamine-2′-β-N-oxide, along with one new dialdehyde, hernandial, have been isolated and characterized from the trunk bark of Hernandia nymphaeifolia. The structures of these compounds were elucidated by spectral analyses.     

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.     

New natural cholinesterase inhibiting and calcium channel blocking quinoline alkaloids

During this study, one new coumarin; 7-O-beta-D-glucopyranoside-2H-1-benzopyran-2-one (1) and three quinoline alkaloids; 3-hydroxy, 2, 2, 6-trimethyl-3, 4, 5, 6-tetrahydro-2H-pyrano[3,2-c] quinoline 5-one (2), ribalinine (3) and methyl isoplatydesmine (4) were isolated from the aerial parts of Skimmia laureola and their structures established by spectroscopic studies. Compounds 2-4 were found to be linear mixed type inhibitors of acetylcholinesterase (K(i) = 110.0, 30.0 and 30.0 microM, respectively). Compounds 2 and 3 were also found to be linear mixed type inhibitors of butyrylcholinesterase, while compound 4 was a noncompetitive inhibitor of the enzyme (K(i) = 90.0, 70.0 and 19.0 microM, respectively). The inhibition of acetyl- and butyryl-cholinesterase enzymes persists as the most promising therapeutic strategy for activating the impaired cholinergic functions in Alzheimer's disease and related dementias. Compound 4 also showed dose-dependent spasmolytic activity in the isolated rabbit jejunum intestinal preparation by relaxing the spontaneous (EC50 = 0.1 mg/mL) and K(+)-induced contractions (EC50 = 0.4 mg/mL), suggesting that the spasmolytic effect of compound 4 is mediated through the blockade of voltage-dependent Ca2+ channels.     

Stereochemistry of tropane alkaloid formation in Datura

Five-month-old Datura innoxia plants were fed via the roots with either d(+)-hygrine-[2′-¹⁴C] or l(?)-hygrine-[2′-¹⁴C]. After 7 days the root alkaloids 3α,6β-ditigloyloxytropane, 3α,6β-ditigloyloxytropan-7β-ol, hyoscine, hyoscyamine and cuscohygrine were isolated from both groups of plants. d(+) but not l(?)-hygrine acts as a precursor for the tropane alkaloids whereas both enantiomers appeared to serve equally well in the biosynthesis of cuscohygrine.     

Two cage-type lupin alkaloids from Sophora franchetiana

Two new cage-type lupin alkaloids, (?)-tsukushinamine-B and tsukushinamine-C, have been isolated from the fresh epigeal parts of Sophora franchetiana, along with (?)-cytisine, (?)-N-formylcytisine, (?)-rhombifoline, (?)-anagyrine, (?)-baptifoline and (±)-ammodendrine, as well as (?)-tsukushinamine-A. The structures of these novel tsukushinamine-type lupin alkaloids were determined by spectroscopic data and partly by a chemical reaction. Variations of the alkaloid contents in the seeds, seedlings and various parts of S. franchetiana were also examined.     

Grandifloroside et methylgrandifloroside,glucosides iridoides nouveaux d'Anthocleista grandiflora

From the bark of Anthocleista grandiflora, two new iridoïd glucosides were isolated, and their structures established.     

Minor alkaloids of Heliotropium curassavicum

Isolation and structure determination of the minor alkaloids of Heliotropium curassavicum are described. These include the new pyrrolizidine alkaloids, heliocurassavine [isoretronecanol (?) curassavine], heliocoromandaline [isoretronecanol (+) viridiflorate], heliocurassavicine [isoretronecanol (?) trachelanthate], heliocurassavinine [laburnine (?) trachelanthate], curassavinine [supinidine (?) curassavate], coromandalinine [supinidine (+) viridifloratel, heliovinine [supinidine (?) trachelanthate] and curassanecine [1-(α-hydroxy-methyl)-8α pyrrolizidin-1β-ol]. Structures were established by high resolution ¹H NMR, mass spectrometry and paper electrophoresis of the alkaloids and their hydrolysis products.     

An azole, an amide and a limonoid from Vepris uguenensis (Rutaceae)

The limonoid derivative, methyl uguenenoate, the azole, uguenenazole, and the amide, uguenenonamide, together with the known furoquinoline alkaloids flindersiamine and maculosidine, and syringaldehyde have been isolated from the root of the East African Rutaceae Vepris uguenensis. While methyl uguenenoate and the furoquinoline alkaloids displayed mild antimalarial activity, the azole and amide were completely inactive.     

Three new alkaloids from Buxus papillosa

Three new steroidal alkaloids have been obtained from Buxus papillosa Schneider. These are (?)-cyclobuxupaline-C (IV)(+)-cyclopapilosine-D (VII) and (+)-buxamine-C (IX). A known alkaloid also present is desoxy-16-buxidienine (X).     

Antimicrobially active alkaloids from Tabernaemontana pachysiphon

Twenty-three alkaloids and five steroids and triterpenes have been isolated and identified from the root bark and stem bark of a Nigerian Tabernaemontana pachysiphon. The following bases have not previously been obtained from this species: isositsirikine, 16-epiisositsirikine, normacusine B, 16-epiaffinine, anhydrovobasindiol, tubotaiwine, ibogaline, isovoacangine, voacamine, lochnericine, 3R-hydroxyconopharyngine, 3S-hydroxyconopharyngine and 11-demethylconoduramine, the last three being new alkaloids. The dimeric indole alkaloids and 3R/S-hydroxyconopharyngine were shown to possess strong antibacterial activity against Gram-positive bacteria and the dimers against Gram-negative bacteria also.     

Alkaloids of Sri Lankan Strychnos nux-vomica

Twenty-two identified alkaloids have been isolated from the root bark and leaves of a Sri Lankan Strychnos species supplied as S. nux-vomica. T     

Chromanones de l'écorce de Calophyllum recedens

Three new compounds, recedensolide Ia, recedensic acid IIa and isocalolongic acid IIIa, have been isolated from Calophyllum recedens bark (Gutt     

Two flavonoids from tephrosia purpurea

Purpurenone, a new β-hydroxychalcone; (+)-purpurin, a diastereoisomer of(?)purpurin; dehydroisoderricin, and (?)-maackiain have been isolated from the roots of Tephrosio purpurea in addition to the earlier reported flavonoids [1, 2]. Pseudosemiglabrin was obtained in admixture with (?)-semiglabrin     

Chemical examination of the roots of Terminalia arjuna—the structures of arjunoside III and arjunoside IV,two new triterpenoid glycosides

The non-phenolic fraction of the alcoholic extract of the root bark of Terminalia arjuna yielded two new triterpenoid glycosides, arjunoside III and arjunoside IV in addition to arjunglucoside I and arjunetin. The structure of arjunoside III was established as the 28-β-d(+)-glucuronopyranoside of arjunic acid by a study of its chemical and spectroscopic (¹H and ¹³C NMR) data. Arjunoside IV was shown to be the 3-O-α- l(?)-rhamnoside of arjunic acid. Leucocyanidin, ellagic acid and gallic acid have been isolated from the phenolic part of the root extract.     

Alkaloids of Alstonia macrophylla

A new alkaloid, 19-hydroxyvincamajine, has been isolated from the leaves of Alstonia macrophylla. In addition to this, eight other indole alkaloids, alstonerine, alstophylline, macralstonine, anhydromacralstonine, talcarpine, vincamajine, vincorine and cabucraline, were also isolated and identified from the bark and leaves of A. macrophylla of Sri Lanka. The last five alkaloids have been isolated for the first time from this species and the ¹³NMR of alstonerine and alstophylline are reported.