Fagara coco

The Fagarines. In 1933 Stuckert isolated cocoberine (amorphous) from the bark of Fagara Coco (Gill), England, and from the leaves of the same plant the following five alkaloids —... 

Aegle marmelos, Dictamnus angustfolius, Flindersia spp., Fagara coco, F. spp., Haplophyllum spp., anthoxylum spp. (Rutaceae)... 

Quinoline and Acridone Alkaloids.—Earlier studies have shown that the quinoline nucleus of skimmianine (38) and dictamnine (37) is derived from anthranilic acid and acetate. Whilst incorporation of mevalonate into dictamnine in Dictamnus albus and into the furanoquinoline alkaloids of Skirnmia japonica could not be demonstrated, positive results have been obtained in Fagara coco. [4- " C]Mevalonic acid, [5- " C]mevalonic acid, and [l- " C]dimethylallyl alcohol were satisfactorily incorporated into skimmianine (38) and the activity was confined essentially to C-2, C-3, and C-3 respectively. 

The biosynthesis is closely related to the already established route to the quinoline system of the furanoquinoline alkaloids such as skimmianine (107) (Scheme 25). Two papers have been published this year on the biosynthesis of (107) but they add nothing new to the earlier work reviewed last year.73 Briefly, the results confirm that (i) C(2) and C(3) of the furan ring of (107) are derived in Fagara coco plants from C(4) and C(5) respectively of mevalonic acid,74 (ii) in the same plant, activity is incorporated specifically at C(3) of the furan from C(l) of dimethylallyl alcohol,75 and (iff) 2,4-dihydroxy[3-14C,15N]quinoline (106) is an efficient and specific precursor of the quinoline system of (107) in Ruta graveolens and is incorporated without randomization.75 Surprisingly, the isomer kokusaginine (108) showed a random incorporation in this experiment. 

While isoquinolines are elaborated by a number of natural orders, there are only two exceptions to the statement that the protopine bases are found only in the Papaveraceae. These exceptions are the occurrence of a-al-locryptopine ( S-homochelidonine) in Zanthoxylum brachyacanthum F. Miill. and in Z. coco Gill. Fagara coco (Gill.) Engl.), plants belonging to the Rutaceae, and of protopine in Nandina domestica Thunb. (Berberidaceae). 

The biosynthesis of the furan moiety was investigated for skimmianine, a dictamnine-related alkaloid, using Fagara coco (Rutaceae). Thus, when C-4- or C-5-labeled 3R-mevalonic acid was used in the biosynthetic pathway, C-labeled skimmianine was observed in both cases. When the labeled skimmianine was degraded, radioactive skimmianic acid was obtained from C-4-labeled 3R-mevalonic acid, but radioinactive skimmianic acid was obtained when C-5-labeled 3R-mevalonic acid was fed. Consequently, it was concluded that the C-T and C-2 carbons (furan moiety) of skimmianine were derived from the C-5 and C-4 carbons of mevalonic acid, respectively [4].The biosynthetic precursor of dictamnine is therefore a quinoline alkaloid with a prenyl moiety, derived from dimethylallylpyrophosphate (DMAPP), at the C-3 position, such as platy-desmine [5]. It was also shown that the methyl carbon of the methoxyl moiety at the C-4 position of skimmianine was derived from methionine. 

V. stolzii [44], Zanthoxylum angolensis (Fagara angolensis), Z. capensis (F. capensis), Z. chalybea (F. chalybea), Z. coco (F. coco), Z. macrophylla (F. macrophylla),... 

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