Alkaloids,limonoids and furocoumarins from three Mexican Esenbeckia species

The chemical constituents of three Mexican Esenbeckia species have been determined. Rutaevin was the main limonoid present in the seeds of all three species, E. litoralis, E. flava and E. berlandieri. The husks, leaves, wood and bark contained a wide array of known furocoumarins and furoquinoline alkaloids. In addition, 1-hydroxy-3-methoxy-N-methylacridone was obtained from E. litoralis bark and a new natural 2-quinolone alkaloid, formulated as 3,3-diisopropyl-N-methyl-2,4-quinoldione, was obtained from E. flava wood. The structure was assigned from spectroscopic considerations and conversion to N-methylhaplofoline.     

Kokusaginine and evolitrine from Acronychia pedunculata

Kokusaginine and evolitrine are the major alkaloids present in Sri Lankan Acronychia pedunculata. The Indian variety of Acronychia laurifolia collected in Madras does not contain these alkaloids.     

A 2-Quinolone alkaloid from Almeidea guyanensis

From Almeidea guyanensis, besides N-methylatanine, N-methylflindersine, N-methylkhaplofoline and 4-demethyl-N-methylatanine, a new 2-quinolone, almeine, has been isolated and its structure elucidated as 4-isopropenyl-N-methyl-3,4-dihydrofuro-2-quinolone.     

Alkaloids from Pelea barbigera

From the rutaceous Hawaiian shrub Pelea barbigera we have isolated the furoquinoline alkaloid kokusaginine, the 4-quinolone isoplatydesmine, and a     

Alcaloides d'Araliopsis soyauxii. Isolement d'un nouvel alcaloide,l'Araliopsine

Six alkaloids have been isolated from root bark of Araliopsis soyauxii. Five are known, maculine, flindersiamine, skimmianine, (?) ribalinine, (+) isoplatydesmine and the sixth, araliopsine is new; its structure has been established as hydroxyisopropyldihydrofuro-2-quinolone. From the trunk bark four alkaloids have been isolated: flindersiamine, kokusaginine (?) ribalinine, (+) isoplatydesmine.     

A comparative study on the alkaloids of Zanthoxylum leprieurii, Z. lemairei and Z. rubescens from Ghana

Previous reports on the alkaloids of Z. leprieurii, Z. lemairei and Z. rubescens are reviewed. The alkaloids from nine specimens collected in Ghana have been examined chromatographically and the implications of the findings discussed, with special reference to the distinction between Z. leprieurii and Z. rubescens. In addition three further compounds, dihydrochelerythrine, lupeol and sesamin are reported for the first time from Z. leprieurii. The overall value of alkaloids as systematic markers in Zanthoxylum in Africa is briefly discussed.     

Alkaloids from Haplophyllum suaveolens

Flindersine, γ-fagarine, kokusaginine and one new alkaloid of the flindersine-type were isolated from the aerial parts of Haplophyllum suaveolens. Spectral methods were used to determine the structures of the alkaloids.     

Formation of edulinine and furoquinoline alkaloids from quinoline derivatives by cell suspension cultures of Ruta graveolens

The formation of furoquinoline alkaloids and of edulinine, elaborated by cell suspension cultures of Ruta graveolens, was found to occur by way of 4-hydroxy-2-quinolone. Other substrates transformed to furoquinolines included 4-hydroxy- and 4-methoxy-3-(3-methyl-2-butenyl)-2-quinolone, known earlier as natural precursors in studies with whole plants. Involvement of dictamnine as a natural precursor of 8-methoxydictamnine (γ-fagarine) and skimmianine was proved using ¹⁴C-labelled compounds. Edulinine in the cell suspensions was formed from such substrates as 4-hydroxy-N-methyl-2-quinolone, 4-hydroxy-3-(3-methyl-2-butenyl)-N-methyl-2-quinolone and its 4- methyl ether; this is probably the natural biosynthetic sequence. Changes in alkaloid yields were noted upon prolonged subculturing.     

Ravesilone,a quinolone alkaloid from Ravenia spectabilis

A new quinolone alkaloid designated ravesilone has been isolated from the leaves of Ravenia spectabilis. From spectral evidence the structure of the compound has been established as 3,4,5,6-tetrahydro-7-hydroxy-2,2,6-trimethyl-5-oxo-2H-pyrano[3,2-c]quinoline.     

Alkaloids and flavonoids of Melicope indica

The following substances were isolated from the leaves of Melicope indica: N-methylatanine dictamnine, evolitrine, meliternatin, melibentin and a new flavonoid which was shown to be 3,5,8-trimethoxy-6,7: 3′,4′-dimethylenedioxyflavone by its spectroscopic properties.     

Alkaloids from Haplophyllum buxbaumii

In addition to the known alkaloids kokusaginine, skimmianine, γ-fagarine and a lignan, justicin B, the aerial parts of Haplophyllum buxbaumii afforded three new alkaloids: 4,5,6-trimethoxyfuroquinoline, 4,5,7-trimethoxyfuroquinoline and N-hydroxymethylflindersine. The structures of the known and the new compounds were assigned by spectral methods.     

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.