Ursane Group

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.  

The methyl resonances in the proton spectra of a series of ursenes have been assigned.  

Tachibana, S. Yamada, T. Tsuyuki, and T. Takahashi, Bull. Chem. Soc. Japan, 1977, 50, 469. 

Takani, K. Kubota, M. Nozawa, T. Ushiki, and K. Takahashi, Chem. and Pharm. Bull. (Japan), 1977, 25, 981. 

New natural products include ursonic aldehyde (3-oxours-12-en-28-al) from Dragon s Blood, a resin from Daemonorops draco (Palmae),135 dulcioic acid (168) from Scoparia dulcis (Scrophulariaceae),136 rubifolic acid (169) from Rubia cor-difolia (Rubiaceae),137 esculentic acid (2a,3a,23-trihydroxyurs-12-en-28-oic acid) 

Kanaoka, S. Yano, H. Kato, and N. Nakano, Chem. Pharm. Bull., 1981, 29, 1533. 

Kikuchi, M. Niwa, M. Takayama, T. Yokoi, and T. Shingu, Chem. Pharm. Bull., 1980, 28, 1999. 

A novel dimethyl ester -lactone from Dammar resin has been shown to have the structure (210) by AT-ray analysis. A very probable biogenesis from asiatic acid [(211)— (212) (210)] has been suggested. Madasiatic acid (213), a close relative of asiatic and madecassic acids, has been isolated from Centella asiatica Protection of the vicinal diol system, followed by oxidation to the 6-ketone and Wolff-Kishner reduction yielded 2o,3)5-dihydroxyurs-12-en-28-oic acid. Rubitic 

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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. 

M. N. Laszczyk, Pentacyclic triterpenes of the lupane, oleanane and ursane group as tools in cancer therapy, Planta Med. 2009.75,1549-1560. 

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... 

The main kind of anti-inflammatory triterpenes isolated have oleanane, ursane, taraxastane, lupane and lanostane skeletons (Table 1). Some minor compounds such as hopane are included in other structural groups. Other anti-inflammatory triterpenes like the different cucurbitacins are not included in this review because of their high toxicity. 

This structural group is divided into two subgroups, 3 P-hydroxy-urs-12-ene (Table 7) and 3a-hydroxy-urs-12-ene (Table 8). The ursane (3-boswellic acid and its derivatives have been studied in vivo and in vitro as anti-inflammatory agents. 

Ursane. C30H52, Mr 412.74, see figure under triter-penes. The pentacyclic, saturated triterpene skeleton, substituted by 8 methyl groups, of ursolic acid and a- amyrin. 

The 3p-hydroxy triterpenes of the oleanane, ursane and lupane series have been converted to the 2-deoxy- and 2,6-dideoxy-a-L-arafcmo-hexopyranosyl derivatives by addition processes applied to L-glucal and L-rhamnal. p-Gluco-sides of diol 78 (R = R = H) have been made with the sugar bonded separately to each of the hydroxyl groups. ... 

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. 

The second group contains oleananes (644), ursanes (649), friede-lanes (647), danunaranes (636), shionanes (639) and others. They are derived from squalene (627) in the chair-chair-chair-boat conformation... 

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