Clerodane diterpenes from Baccharis genus

The most widespread diterpenes reported in Baccharis genus are clerodanes, but labdane- and kaurane-type, and to a lesser extent beyerane-type diterpenoids have also been isolated. The investigation of ten Baccharis species afforded four new enr-labdane diterpenes from Baccharis oxydonta... 

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. 

Characteristic constituents from the Baccharis genus, one member of the Compositae, are the neo-clerodane type diterpenes. For example, the aerial parts of B. trinervis, a representative of which is used in South American folk medicine, furnished 24 neo-clerodane type diterpenes, many of them new, e.g., methyltrineracetal, Fig. (1) and epi-methyltrineracetal, Fig. (2) [19],... 

Tortoriello and Aguilar-Santamaria [120] investigated in detail the spasmolytic mechanisms of action of one of these plants, B. serraefolia. The results suggest that the extract does not interact with classical receptors and its effects, at least that produced on smooth muscle, may be due to a probable interference with calcium influx and/or calcium release from an intracellular store. Different chemical compounds, such as clerodane diterpenes and flavonoids, which are typical constituents from the Baccharis genus, have been considered as the active principles of many spasmolytic drugs. A bioassay-monitored fractionation of an extract from B. genistelloides yielded a mixture that blocked the calcium-induced contractions of KCl-depolarized rat portal vein preparations [121], Pharmacological tests of two pure compounds isolated from the mixture revealed a dilactonic clerodane-diterpene, Fig. (70) as the active compound. 

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