Lupane (fabric group)

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The lupans are a group of triterpenes with a pentacyclic structure. Like all triterpenes, lupans are made up of six isoprene units and therefore usually have 30 carbon atoms. Lupans have a structure of four six-membered rings and one five-membered ring. The main body Lupan C 30 H 52 (CAS number 464-99-3) has methyl groups in positions 4, 4, 8, 10, 14 and 17 and an isopropyl residue in position 19.

Structural formulas of important lupans

The Lupan skeleton is based on that of Baccharan; Lupans therefore belong to the triterpene subgroup of the bacchara type.

Structural formulas of lupane and baccharan

  • Lupan C 30 H 52

  • Baccharan

Historical

Johann Tobias Lowitz isolated betulin from birch bark; he published his study in 1788. The discovery of Lupeol was announced in 1891 by Arthur Likiernik; he isolated it from yellow lupins ( Lupinus luteus ) during his doctoral thesis with Ernst Schulze and named it after this origin. Schulze later found Lupeol in white lupins ( Lupinus albus ).

In 1971 a total synthesis by Lupeol was published.

Occurrence and isolation

The plants of the species Euonymus carnosus belonging to the spindle bushes are a rich source for various lupans

Betulin forms up to 30% of the dry matter of the bark of the silver birch Betula verrucosa and can easily be obtained from it by extraction with chloroform . Lupeol is found in fruits, such as mango or strawberries , and in vegetables .

Use and possible applications

The betulin-containing drug Episalvan has a European approval for the treatment of dermal wounds in adults. Betulin is used as an emulsifying additive in shampoos .

There is a body of evidence that lupans, especially betulin, betulinic acid, and lupeol, may have preventive and curative effects against cancers.

Related groups of substances

The hopanoids have the same structure as the lupans in the four six-membered rings, but differ in the substitution pattern on the five-membered ring. Further subgroups of the triterpenes are the oleananes and the ursans .

Individual evidence

  1. ↑ Johann Tobias Lowitz : About a new, almost benzo-like substance of the birch trees. In: Lorenz Crell (Ed.): Chemische Annalen . for friends of the natural sciences, knowledge of Arzney, housekeeping and manufactories. tape 1788 , no. 1 . Fleckeisen / Müllersche Buchhandlung, Helmstädt and Leipzig 1788, OCLC 609930568 , p. 312–316 ( online at the Bayerische Staatsbibliothek digital): "several logs of young birch trees with white bark, erect, so close to a very quiet fire"
  2. ↑ Arthur Likiernik: About the Lupeol . In: Reports of the German Chemical Society . tape 24 , no. 1 . Berlin January 1891, p. 183–186 , doi : 10.1002 / cber.18910240135 ( online at Gallica Bibliothèque nationale de France).
  3. ↑ Arthur Likiernik: About the vegetable lecithin and about some components of the legume shells . Inaugural dissertation. Zurich 1891 ( summary (E. Roth) in the Botanisches Centralblatt 1892 online [PDF]).
  4. ↑ https://archive.org/details/botanischeszentr2597bota/page/208
  5. ↑ Gilbert Stork , Shoichiro Uyeo, T. Wakamatsu, P. Grieco, J. Labovitz: Total synthesis of lupeol . In: Journal of the American Chemical Society . tape 93 , no. September 19 , 1971, p. 4945-4947 , doi : 10.1021 / ja00748a068 .
  6. ^ Robert A. Hill, Joseph D. Connolly: Triterpenoids . In: Natural Product Reports . tape 35 , no. 12 , 2018, p. 1294-1329 , doi : 10.1039 / C8NP00029H .
  7. ^ Brian Green, Michael D. Bentley, Bong Y. Chung, Nicholas G. Lynch, Bruce L. Jensen: Isolation of Betulin and Rearrangement to Allobetulin. A Biomimetic Natural Product Synthesis . In: Journal of Chemical Education . tape 84 , no. December 12 , 2007, pp. 1985 , doi : 10.1021 / ed084p1985 .
  8. ↑ Niege JC Furtado, Laetitia Pirson, Hélène Edelberg, Lisa M. Miranda, Cristina Loira-Pastoriza: Pentacyclic Triterpene Bioavailability: An Overview of In Vitro and In Vivo Studies . In: Molecules . tape 22 , no. 3 , March 4, 2017, p. 400 , doi : 10.3390 / molecules22030400 , PMID 28273859 , PMC 6155290 (free full text).
  9. ^ Charles Gauthier, Jean Legault, Marianne Piochon-Gauthier, André Pichette: Advances in the synthesis and pharmacological activity of lupane-type triterpenoid saponins . In: Phytochemistry Reviews . tape 10 , no. 4 , December 2011, p. 521-544 , doi : 10.1007 / s11101-010-9176-y .
  10. ↑ MH Cháirez-Ramírez, MR Moreno-Jiménez, RF González-Laredo, JA Gallegos-Infante, Nuria Elizabeth Rocha-Guzmán: Lupane-type triterpenes and their anti-cancer activities against most common malignant tumors: A review . In: EXCLI Journal 2 . November 30, 2016, p. 758–771 , doi : 10.17179 / excli2016-642 , PMID 28337107 , PMC 5318673 (free full text) - ( excli.de [PDF]).