Baccharis species diterpene derivatives

To date more than 100 species from the large genus Baccharis have been investigated chemically. The most widespread compounds are clerodane diterpene derivatives, but labdane derivatives have also been isolated. Furthermore, typical acetylenic compounds, baccharis oxide, a unique triterpene, and derivatives of hydroxyacetophenone are present, although it is mainly other biologically active constituents, e.g. flavonoids, sesquiterpenes and essential oils that have been reported in the last years. The constituents of Baccharis species compiled from different sources are presented below. 

Bohlmann F, Knauf W, King RM, Robinson H 1979 Naturally occurring terpene derivatives. 196. A new diterpene and additional constituents form Baccharis species. Phytochemistry 18 1011-1044... 

Bohlmann F, Zdero C, Grenz M, Dhar AK et al. 1981 Naturally occurring terpene derivatives. Part 307. Five diterpenes and other constituents from nine Baccharis Species. Phytochemistry 20 281-286... 

Looking more closely at the diterpene-producing species, it is apparent that Baccharis produces relatively more e zMabdanes and related skeletons than were found in Brickellia and Stevia (Table 9, [pp. 447-449], Figures 23 [p. 469], 24 [pp. 470-473], and 25 [pp. 474-475]). The most common of these skeletons is the 5a,l0 -trans-ent-clerodane. Among the e f-skeletal classes, there is a rough mutual exclusivity of the trans-clerodanes and the polycyclic compounds (e.g., e /-kaurenes). Normal-labdanes and derivatives occur rarely within this genus. 

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