Ursane Triterpenoid

Many oleane and ursane triterpenoids are reported to have interesting biological, pharmacological, and medicinal activities similar to those of retinoids and steroids. These include antiinflammatory activity, suppression of tumor promotion, suppression of immunoglobulin synthesis, protection of the liver against toxic injury, induction of collagen synthesis, and induction of differentiation in leukemia or teratocarcinoma cells [197]. 

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]. 

Tissue cultures of Isodon japonicus could biosynthesize oleanane- and ursane-type triterpenoids from [4-13C]MVA with sufficient incorporation of tracer to allow the elucidation of the labelling pattern by 13C n.m.r. spectroscopy.356 The results verify the hypothesis of Ruzicka involving cyclization of 2,3-oxidosqualene in a chair-chair-boat form, followed by specific 1,2-hydride shifts, and the rearrangement of... 

The interesting biological properties shown by many saponins, coupled with improvements in spectroscopic methods of structure determination have led to the increased study of this class of compound. The following papers deal with saponins and prosapogenins which are based on known triterpenoids of the following groups dammarane-euphane,158 lupane,159 oleanane,160 and ursane.161... 

Triterpenoids are widely distributed throughout the plant kingdom. Oleananes and ursanes, which often occur together, and lupanes are found... 

Phytochemistry Flowering plant tops contain 0.01-0.04 % essential oil (similar to Salvia sclarea in composition) with a pleasant aroma. In leaves there were 47 mg% vitamin C, and seeds contained up to 19 % oil (Khalmatov 1964). Triterpenoids, including ursane, oleanane, and lupane derivatives were isolated from the aboveground parts (Savona et al. 1987). The roots were found to contain a number of caffeic acid derivatives (rosmarinic acid, Uthospetmic add B, etc.), diterpenes (royleanone, ferruginol, taxodione, etc.), and the steroid daucosterol (Tezuka et al. 1998). 

Centella asiatica Ursane-type triterpenoid Asiatosides... 

Preparative TLC and high-resolution (HR) EI-MS were used for isolation of santolinoic acid, a new ursane-type triterpenoid, from Salvia santolinifolia [31]. Partitioning of the ethanolic extract with different solvents was followed by column... 

Ahmad, Z., Mehmood, Z., Ifzal, R., Malik, A., Afza, N., Ashraf, M., and Jahan E. 2007. A new ursane-type triterpenoid from Salvia santolinifolia, Turk. J. Chem., 31 495-501. 

The triterpenoid constituents of resins analysed are usually seen as a group of peaks eluting at around 30 minutes retention time under the analytical conditions used. Of the triterpenoid resins in Table I, four of the five come from the Dipterocarpaceae family. Their complexity and triterpenoid composition varies to some degree, but common to all are a number of peaks identifiable as compounds from the tetracyclic dammarane series (Figures 3-6). In addition to these, pentacyclic triterpenoids from the ursane and oleanane series are present. Although some peaks have yet to be conclusively identified, they are included since they are detected in more than one of the Dipterocarp reference samples and have also been observed in some archaeological material. 

Similar rearrangements in the ursane series (cf. cation 530) are known but appear to be of minor consequence in elaborating new compounds no more than a dozen triterpenoids belonging to all these types (cf. Fig. 8.1.32) have been isolated so far. Of these, only baueranes (corresponding to the multiflorane type) (Fig. 8.1.32) have been encountered in woody tissues. Thus, the simplest member, bauerenol (554), has been found to occur in the barks of Acronychia baueri and Ilex crenata (229). Phyllanthol (555), from the root-bark of Phyllanthus engleri, represents an alternative fate for the isoursane cation (ursane equivalent of cation 543) (109, 228). 

This review summarizes, up to mid 2014, the most representative microbial transformations and the derivatives of special interest obtained from the lupan-type (lupeol), olean-t) e (p-amyrin), and ursan-type (a-amyrin) pentacyclic triterpenoids (Figure 28.1) in the last 20years. 

J. A. R. Salvador, V. M. Moreira, B. M. F. Goncalves, A. S. Leal, Y. Jing, Ursane-type penta-cydic triterpenoids as useful platforms to discover anticancer drugs, Nat. Prod. Rep. 2012. 29,1463-1479. 

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