Triterpenic compounds

The fatty/waxy products contained the lipophilic substances, including fatty oils, waxes, resins and colorants. Valuable pharmacological effects were proved for some minor constituents of these products (e.g. triterpenes, diterpenes, sterols and carotenoids). Thin layer chromatography and on-line UV-VIS spectroscopy were used for the quick identification and quantity determination of these compounds using authentic samples as standards. The SFE method proved favorable in terras of both extraction yield and speed of carotenoids. The CO2 extracts of the lavandin, clary sage and thyme have been enriched in triterpenic compounds (a-es P-amyrin, oleanic acid, ursolic acid, etc.) and phytosterols. Both free and esterified triterpenoids were present in the extracts of the different samples. Furthermore camosol and other diterpenes were detected in the SFE extract of Lamiaceae plants. The fatty acid composition was only slightly different for extracts obtained by SFE and conventional hexane extraction. 

In the oleanane-ursane group of triterpenes, postulated hydride shifts [as proposed by Eschenmoser and co-workers (1955)] have now been demonstrated. Incorporation of [4- C]MVA into oleanolic acid (56), ursolic acid (63), and several other metabolites was accomplished with tissue cultures of Isodon japonicus (Lamiaceae). Following introduction of [4- C]mevalonate and [l,2- C2]acetate, the pentacyclic triterpene compounds were examined by C-NMR spectroscopy. Rings D and E were formed by the routes predicted by Eschenmoser et al. (1955). The labeling pattern at carbons 4,23, and 24 of 3- p/-maslinic acid (64) indicates that this series is formed from (35)-squalene epoxide, rather than from the (3R)-epimer. 

Bogatkina, V.F., I.A. Murav ev, E.F. Stepanova, and N.P. Kir yalov Triterpene Compounds from the Epigeal Mass of Glycyrrhiza glabra. Khim. Prir. Soedin., 1974, 101 Chem. Nat. Comp. (Engl, transl.), 10, 114 (1976). 

In addition, GA has also been suggested to possibly transactivate nuclear receptor peroxisome proliferator-activated receptor (PPAR) class of nuclear receptors triterpene compounds (such as 2-cyano-3,12-dioxooleana-l,9-dien-28-oic acid (CDDO) and dehydrotrametenolic acid) have been found to bind to and transactivate PPARy [25, 26]. This may suggest that GA, a triterpenoid compound, could also possibly transactivate (PPAR) class of nuclear receptors. 

Laugel C, Rafidison P, Potard G, Aguadisch L, Baillet A. 2000. Modulated release of triterpenic compounds from a OAY/O multiple emulsion formulated with dimethi-cones Infrared spectrophotometric and differential calorimetric approaches. J Controlled Release 63 7-17. 

Terpenes (Section 26.7) Compounds that can be analyzed as clusters of isoprene units. Terpenes with 10 carbons are classified as monoterpenes, those with 15 are sesquiterpenes, those with 20 are diterpenes, and those with 30 are triterpenes. 

Sometimes several of these rearrangements occur in one molecule, either simultaneously or in rapid succession. A spectacular example is found in the triterpene series. Friedelin is a triterpenoid ketone found in cork. Reduction gives 3p-friedelanol (47). When this compound is treated with acid, 13(18)-oleanene (48) is formed. In this case seven 1,2 shifts take place. On removal of H2O from position 3 to leave a positive charge, the following shifts occur hydride from 4 to 3 methyl... 

Fig. 2.12 Compounds 57-59, triterpene methyl ethers (TMEs), from Chionochloa. Compounds 60-64, lichen-acid derivatives from European Ramalina siliquosa...

Fig. 2.63 Compounds 206, an alkaloid, and 207-209, sesquiterpenes from Gaillardia pulchella. Compounds 210 and 211, triterpenes from Dudley a...

The brownish colored zone (Rj 0.28) of incensole (compound 3), which occurs in both the resin and the volatile fractions of B. carterii, draws the hue between the volatile diterpenes and the nonvolatile triterpenes. B. carterii reveals two further colored prominent spots, a yellowish-ochre (Rf 0.65) of incensole acetate (compound 2) and a violet-colored spot (Rj 0.98) of verticilla-4(20),7,ll-triene (compound 1). Lane 2 and lane 3 reveal a light blue area (Rj 0.60) of 1,8-cineol that is only visible in freshly distilled oils. 

The GC-MS data (Figure 16.11) of the violet zone of B. carterii revealed that the unchanged diterpenes (verticillatriene, cembrene A, and cembrene C) and the nortriterpenes with carbohydrate structure originated from the pyrolyzed triterpenes (Figure 16.12) of the a- and (3-boswellic acids, named 24-norursa-3,12-diene (compound 7), 24-norursa-3,9(ll),12-triene (compound 8), 24-noroleana-3,12-diene (compound 9), and 24-noroleana-3,9(ll),12-triene (compound 10). 

Common pharmaceutical products of olibanum and salai guggul are tablets prepared from dried extracts of boswellic adds, which are obtained by processes involving treatment of the resins with alkali and acid. The stress involved in this treatment is expected to lead to alteration of some triterpenes as, e.g., the conversion of the unstable 3-(9-acetyl-ll-hydroxy-[3-boswellic acid (compound 12) to the stable compound 3-(9-acetyl-9,ll-dehydro-[3-boswellic acid (compound 13). Two-dimensional TLC is an excellent means of observing this conversion [5]. For verification of this process, the substances have to be isolated by PLC and identified by GC-MS. 

From a chemical point of view, vegetable resins are a complex mixture of mono-, sesqui-, di- and triterpenes, which have, respectively, 10, 15, 20 and 30 carbon atoms per molecule. The mono- and sesquiterpenes are both present in most resins. The di- and triterpenes are rarely found together in the same resin, which means that terpenic resins can be divided into two main classes. Table 1.5 lists the botanical origin and the kind of terpenoid compounds of some natural resins. 

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]. 

The use of HMDS as a derivatization reagent in the analysis of triterpenoid resins has been less explored. The TMS derivatives of triterpenoids bearing hydroxyl groups [a-amyrine, p-amyrine and hop-22(29)-en-3p-ol] have been identified in the triterpenic fraction of Burseraceae resins, thus demonstrating that HMDS combined with Py-GC/MS is effective in the derivatization of triterpenoid compounds [59]. However, the range of structures that can be fully derivatized and detected must be extended and, in order to get comprehensive results comparable with those coming from the well assessed off-line GC/MS procedures, general improvements in the on-line trimethylsilylation-pyrolysis method are needed. 

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