Sebastian Jäger 1,*, Holger Trojan 1, Thomas Kopp 1, Melanie N. Laszczyk 2 and Armin Scheffler 1
Carl Gustav Carus-Institute, Am Eichhof 30, D-75223 Niefern-Öschelbronn, Germany Betulin-Institute, Blumenstrasse 24, D-64297 Darmstadt, Germany; E-Mail: firstname.lastname@example.org (M-N.L.)
* Author to whom correspondence should be addressed; E-Mail: email@example.com; Tel.: +49 7233 68 410; Fax: +49 7233 68 413
Received: 22 April 2009; in revised form: 26 May 2009 / Accepted: 3 June 2009 / Published: 4 June 2009
Abstract: Pentacyclic triterpenes are secondary plant metabolites widespread in fruit peel, leaves and stem bark. In particular the lupane-, oleanane-, and ursane triterpenes display various pharmacological effects while being devoid of prominent toxicity. Therefore, these triterpenes are promising leading compounds for the development of new multi-targeting bioactive agents. Screening of 39 plant materials identified triterpene rich (> 0.1% dry matter) plant parts. Plant materials with high triterpene concentrations were then used to obtain dry extracts by accelerated solvent extraction resulting in a triterpene content of 50 - 90%. Depending on the plant material, betulin (birch bark), betulinic acid (plane bark), oleanolic acid (olive leaves, olive pomace, mistletoe sprouts, clove flowers), ursolic acid (apple pomace) or an equal mixture of the three triterpene acids (rosemary leaves) are the main components of these dry extracts. They are quantitatively characterised plant extracts supplying a high concentration of actives and therefore can be used for development of phytopharmaceutical formulations.
Keywords: lupane; oleanane; ursane; triterpene dry extract; active plant extracts; triterpene distribution
Molecules 2009, 14
Consumption of fruit and vegetables has been associated with a lower incidence of cancer and other diseases. Diets, especially along the Mediterranean coast, are correlated with healthiness . Mediterranean spices and fruits contain, besides other nutraceuticals, pentacyclic triterpenes from the lupane, oleanane and ursane groups (see Figure 1 and Table 1), that are regularly isolated as active substances from these plants. For example, they can be found in rosemary and other spices of the Lamiaceae family as well as within olive leaves and fruit. Virgin olive oil contains up to 197 mg/kg triterpenes, indicating the importance of these substances as nutraceuticals [1-4]. Furthermore, the bioguided fractionation of several hundred plant extracts led to the isolation of betulinic acid (BA), oleanolic acid (OA) and ursolic acid (UA) as the active principles . Apples are among the fruit most consumed worldwide and anti-tumoral effects from apples are correlated with the fruit peel  which contains OA, UA and maslinic acid (MA) . Known sources for triterpenes are mainly plant surfaces such as stem bark or leaf and fruit waxes .
Figure 1. Molecule structures of lupane-, oleanane- and ursane triterpenes investigated here.
Table 1. Triterpene characterisation.
The pharmacological relevance of these triterpenes has increased during the last two decades demonstrating multi-target properties such as wound healing, anti-inflammatory, anti-bacterial, antiviral, hepatoprotective and anti-tumoral effects, combined with low toxicity [9-13]. Therefore...