Eupatorieae

Wollenweber, E. et al., External flavonoids of 12 species of North American Eupatorieae (Aster-aceae), Z. Naturforsch., 51c, 893, 1996. 

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. 

Eupatorieae Tribe.—Nine Eupatorium species that are found in the U.S.A. have been screened for pyrrolizidine alkaloids by Herz et al.2i Intermedine (42) (crystalline for the first time) and echinatine were isolated from Conoclidium coelestinum (L.) DC. (syn. Eupatorium coelestinum L.). Intermedine (42) and lycopsamine (41) were present in E. compositifolium Walt. These diastereoisomeric diols were separated as their borate complexes.29 Rinderine and 7-angelyl-heliotridine (43) were isolated from E. altissimum L.28... 

The structure of the tran -clerodane dicarboxylic acid haplociliatic acid (62), obtained from Haplopappus ciliatus, was established by X-ray analysis. The presence of the known diterpenoid cw-kolavenic acid has been noted in several members of the tribe Eupatorieae. Some cw-clerodanes [e.g. (63)] have been obtained from the Brazilian Compositae, including Symphiopappus itatiayensis. 

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

The N. bases are mostly esterified by aliphatic mono-ordicarboxylic acids, the so-called necine acids. In the subfamily (tribe) Senecioeae of the Asteraceae the alkaloids occur almost exclusively as 12-membered macrocyclic diesters of variously substituted hexane-dioic acids or as mono- and diesters of Cs acids (angelic, tiglic, and senecioic acids) with retronecine. In the subfamily Eupatorieae of the Asteraceae and the Boragin-... 

Zdero, C., F. Bohlmann, and R.M. King Secolabdanes from Tamaulipa azurea and Constituents from other Eupatorieae. Phytochem., 31, 155 (1992). 

The most important alkaloid containing families are the Amaryllidaceae, Apocynaceae, Asteraceae (Eupatorieae, Se-necioneae), Boraginaceae, Euphorbiaceae, Fabaceae, Laur-aceae, Liliaceae, Loganiaceae, Menispermaceae, Papavera-ceae, Ranunculaceae, Rubiaceae, Rutaceae, and Solanaceae (Cordell, 1978 Dalton, 1991). 

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

In comparison to the macrocyclic PAs of the senecionine type structural diversification of PAs of the lycopsamine type follows a different strategy. The backbone structure is represented by trachelanthamidine the simplest necine base (Fig. 2) esterified with stereoisomeric dihydroxylated 2-isopropylbutanoic acids (Sect. 3.2). The most abundant isomeric necic acids are (-l-)-trachelanthic acid (2 S, 3 R configuration) (Fig. 8) and (-)-viridifloric acid (2 S, 3 S). Necine esters with (-)-trachelanthic acid (2 R, 3 S) or (-i-)-viridifloric acid (2 R, 3 R) have been described but they are rare [3]. In PA-producing species of the family Boraginaceae [16,56] and species of the tribe Eupatorieae [63] oftheAsteraceae, diversification of the backbone structures is initiated by a conunon sequence of consecutive reactions ... 

From the aerial parts of Ophryosporus chilca (Compositae, tribe Eupatorieae)... 

From the genus of Eupatorium riparium Regel and Eupatorium glandulosum H.B. K. (syn. Eupatorium adenophorum Spr.) (Eupatorieae) [4307]. 

Acritopappus confertus (Eupatorieae) produces a pair of unusual tricarbocy-clic compounds, 617 and 618, that do no result from the cyclization processes described above. A biogenetic scheme for these constituents (Figure 17 [p. 429]) invokes an aldol condensation reaction to link C-11 and C-17 (184). 

Figure 5. Proposed biogenesis of e /-labdanes and nor-homologs reported from Ayapana (Eupatorieae, 775).

Figure 14. Proposed route of rosane biogenesis in Trichogonia (Eupatorieae) (183) A. an example of C-13 epimeric pair of rosane compounds (note that the prefix refers not to an entAabdmc origin, bot to the C-13 orientivity relationship of this compound pair B. biogenetic route for sandaracopimarane and rosane constituents of Trichogonia.

As yet, no systematic study focusing on generic-level diterpenoid distribution patterns has been reported for the Compositae. Consequently, little is known about how diterpenes vary within groups of related species. As a partial remedy for this deficiency, diterpene interspecific variation is described for representative genera of the major diterpene-producing tribes Eupatorieae Brickellia, Stevia), Astereae Baccharis), Inuleae (Helichrysum), and Heliantheae (Helh anthus, Montanoa). 

Most of the approximately ninety Brickellia (Eupatorieae Alomiinae) species inhabit the North American deserts, although three species are South American disjuncts. The diterpene chemistries of the ten investigated taxa (Table 6 [p. 441] Figure 19 [pp. 457-461]) are remarkably uniform. Normal-labdanes often characterized by novel 2a,3o -hydroxylation/esterification occur in all diterpene-producing species. In B. eupatoriedes, these 2a,3a-substituted normal-labdanes co-occurred with cleistanthanes and other eAtf-pimarane-derived skeletal types. Production of normal-labdanes together with tri- and polycyclic ewMabdane-derived skeletons is an often-repeated theme in the diterpene chemistries of Compositae taxa. 

Table 6. Distribution of diterpenes in Brickellia (Eupatorieae) species.

Figure 19. Structures of normal-labdanes reported from Brickellia (Eupatorieae) compounds with common substitutional patterns (Scheme A) and with unusual 2a,3a-dihydroxy-pattem (Scheme B). Structures of Brickellia e /-clerodanes [511], cleistan-thanes, etc. [601-609] (Scheme C).

Figure 21. Structures of cwMabdane and c /-kauranoid diterpenes isolated from Stevia (Eupatorieae) e -labdanes and kaurene mono- and di-glycosides (Scheme A) C-13-kaurene-glycosides (Scheme B).

Baruah. R.N., C. Zdero, F. Bohlmann, R.M. King, and H. Robinson Some sesqui- and diterpenes from the tribe Eupatorieae. Phytochem. 24, 2641 (1985). 

Bohlmann, F., P. Zitzkowski, A. Suwita, and L. Fiedler cw-Kolaveninsaure und weitere inhaltsstoffe aus vertretern der tribus Eupatorieae. Phytochem. 17, 2101 (1978). 

Gage, D.A. Chemical data and their bearing upon generic delineations in the Eupatorieae. Taxon 34, 61 (1985). 

Gage, D.A. A Chemosystematic Study of the genus Piptothrix (Compositae, Eupatorieae). Doctoral Dissertation. The University of Texas at Austin (1986). 

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