Senecioneae Tribe

Senecioneae Tribe.—A new dihydropyrrolizinone alkaloid has been isolated from Jacmaia incana (Sw.) B. Nord. by Bohlmann and co-workers.30 The structure (44) for this alkaloid was deduced from 14 n.m.r. and mass-spectral data. The 7/ -configuration was assumed after comparison of the rotation of (44) with those of other related alkaloids. Previously isolated dihydropyrrolizinone alkaloids have all contained macrocyclic rings, as in senaetnine (45). Senaetnine was present in Odontocline hollickii (Britt, ex Greenm.) B. Nord.30 

Pterophorine and inaequidenine, two other dihydropyrrolizinone alkaloids, were previously isolated from Senecio inaequidens DC. (cf. Vol. 8, pp. 54-56). Senecionine and retrorsine have now also been shown to be present in this species.31,32 7-Angelylheliotridine (43) has been isolated from S. ovirensis ssp. gaudinii.32,33 The cause of poisoning in dairy cattle in Switzerland was found to be S. alpinus.34 Nine known pyrrolizidine alkaloids were isolated from this species, and the major constituent was seneciphylline. Otosenine, floridanine, and doronine are present in 5. othonnae.35 The extraction of seneciphylline and platyphylline from S. platyphylloides has been studied by a variety of methods.36 

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Adenostyles and Doronicum, is of chemotaxonomical interest. Pimenov et ai24 have studied the variation in alkaloid content of subspecies of A. rhombifolia (Willd.) Pim. All plants contained varying amounts of platyphylline (42), sene-ciphylline (43), and sarracine. Platyphylline and seneciphylline were also extracted from the roots of A. alliariae.25 The genus Adenostyles has been classified by some taxonomists in the tribe Eupatorieae, but its content of macrocyclic pyrrolizidine alkaloids is in accord with its current position in the Senecioneae. 

The occurrence and distribution of pyrrolizidine alkaloids in members of the tribes Eupatorieae " and Senecioneae have been reviewed. 

C,gH27NO Mr 337.42, mp. 129°C, [aJo -59° (C2H5OH). P. is a pyrrolizidine alkaloid from various genera of the Asteraceae, tribe Senecioneae (Adeno-styles, Senecio, Petasites). It exists in the plants as the (V-oxide. P. does not exhibit hepatotoxicity, isrelatively non-toxic, and has atropine-like activities. It was used in the former USSR for the treatment of stomach diseases. 

Within the family Asteraceae, acetylenic compounds are largely absent from the tribe Senecioneae and are most com-... 

These alkaloids are found mostly in the Asteraceae (tribes Senecioneae and Eupatorieae), the Boraginaceae, Fabaceae (Crotalaria, Lotononis, and Buchenroedera), and a few... 

Within the plant kingdom PAs are only found in the angiosperms. Here they occur quite scattered and often sporadically in phylogenetically unrelated taxa [3]. Major sources for PAs are the Asteraceae tribe Senecioneae (>230 species). 

Four out of nineteen subfamilies of the Chrysomelidae (leaf beetles) possess pronotal and elytral glands that produce and release defensive compounds [106]. So far, only a few species of the genus Oreina belonging to the subfamily Chrysomelinae are known to sequester PAs from their host plants [107]. Chemical defense in chrysomelines is primarily autogenous. Thus, Oreina species feeding on Asteraceae, tribe Senecioneae appear to have moved secondarily to host-derived defense [108]. 

Bohlmann, F., C. Zdero, and M. Grenz Polyacetylene Compounds. Part 241. Constituents of some Genera of the Tribes Helenieae and Senecioneae. Phytochemistry 15, 1309 (1976). 

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