Ursane

Cholit-Ursan (Fresenius- comb. Chenofalk (Thames)... 

Guttiferales Dipterocarpaceae Hopea (dammar) Dammaranes (hydroxydammarenone, dammaradienol), ursanes (ursonic acid, ursonaldehyde)... 

Frankincense, also known as olibanum, is obtained from trees belonging to the genus Boswellia (Burseraceae family). It is one of the best-known ancient plant resins. The ancient Egyptians were the first to use it as incense in embalming practices and in the preparation of medicines, cosmetics and perfumes, and today it is still used therapeutically. It contains pentacyclic triterpenoids belonging to oleanane, ursane or lupane type molecules and in particular of a- and p-boswellic acids, and their O-acetates [104 111], 11 -Oxo-p-boswellic acid and its acetyl derivative, identified in several Boswellia species, are also diagnostic for frankincense [112]. 

Dammar resin was introduced into Europe in the nineteenth century, mainly as a paint varnish It is still used today since it has good optical properties and low acidity. It is derived from various species (the genus Hopea and Shorea of the Dipterocarpaceae family). It is characterised by tetracyclic triterpenoids of the dammarane series and contains minor amounts of pentacyclic triterpenoids of the series of olanane, ursane and hopane. It also contains a polymeric fraction named polycadinene or [S-resene. Dammar resin triterpenoids undergo oxidation with ageing, as described for the components of mastic resin. 

Figure 5.5 Norrish reaction of a triterpenoid (e.g. dammarane, oleanane or ursane type) leading to ring opening and subsequent oxidation of the ketone to the corresponding acid...

Dammar is produced by trees belonging to the Dipterocarpaceae family. It is mainly composed of triterpenoids, but it also contains a polymeric fraction based on polycadinene, a polysesquiterpene [37,38]. The main components of the triterpene fraction are compounds with a dammarane type skeleton and oleane/ursane type molecules [39,40]. 

Jacoumaric acid (200) and jacarandic acid (201) have been isolated from Jacaranda caucana. Three new 13 H-ursane lactones (202)—(204) have been reported from Mallotus repandus. Other new compounds include barbinervic acid (205) from the leaves of Clethra barbinervis and the bauerene derivative myrtifolic acid (206) from the bark of Mesua myrtifolia. ... 

Phytochemical studies of these species led to the isolation and structural characterization, by NMR and MS analysis, of many secondary metabolites, mainly flavonoids, and expecially flavonol glycosides, clerodane diterpenes, and triterpenes having the lupane, ursane, and oleanane skeletons. Particularly flavonoids and their glycosides have a chemotaxonomic interest in the genus and in general in the Chrysobalanaceae family. 

In the course of our phytochemical work we studied seven Licania species all belonging to Venezuelan flora, collected in Puerto Ayacucho, Estado Amazonas and in the Parque Nacional Henry Pittieri, Maracay, Estado Aragua. A number of new and known secondary metabolites, mainly flavonoids, especially flavonol glycosides, sterols, and triterpenes having the lupane, ursane, and oleanane skeleton were isolated and characterized. The last part of this chapter deals also with the isolation of clerodane diterpenes from the methanol extract of L. intrapetiolaris by Oberlies et al., 2001 [4]. All the Licania species investigated up to now are reported in Table 1. 

The use of lanthanide-induced shifts allows distinction between C-29 and C-30 methyl signals in the oleanane and ursane series.91 The 13C resonances of several olean-12-enes have been assigned.92 Experimental verification of Ruzicka s... 

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