Planta Med 2011; 77 - PB30
DOI: 10.1055/s-0031-1282284

Synthesis and cytotoxic activity of new betulin and betulinic acid esters with conjugated linoleic acid (CLA)

C Wawrzenczyk 1, B Tubek 1, P Mitula 1, K Kempinska 2, J Wietrzyk 2
  • 1Department of Chemistry, Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland
  • 2Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Department of Experimental Oncology, Wroclaw, Poland

Novel ester derivatives of betulin (3a-c) and betulinic acid (4) with conjugated linoleic acid (mixture of isomers: 9c, 11t –43.4%, 10t, 12c –49.5%, other isomers –7.1%) were obtained.

Betulin (1) and betulinic acid (2) are natural lupane-type triterpenoids with numerous biological activities: anti-inflammatory, antifungal, antibacterial, antimalarial, antiviral, anticancer [1]. Conjugated linoleic acid (CLA) is group of isomers of linoleic acid, found in milk of ruminants and bovine meat. CLA is known for their antioxidant, antitumor, antiatherogenic properties [2,3]. One can expect that the ester derivatives containing both molecules can also posses the valuable biological activity and they can find an application as medicine for many diseases.

Esterifications of CLA with betulin and betulinic acid were carried out with using of N,N'-dicyclohexylcarbodiimide (DCC) as coupling agent, in presence of 4-dimethylamino-pyridine (DMAP) in dichloromethane for betulin derivatives or in pyridine for betulinic acid derivative respectively.

The cytotoxic activity of betulin (1), betulinic acid (2), mixture of CLA and their derivatives (3a-c, 4) in vitro was determined by performing the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) cytotoxicity assay. Five different cell lines were used: P388 (mouse leukemia), CCRF (human leukemic lymphoblasts), CEM/C2 (camptothecin resistant derivative of the human T cell leukemia cell), Hl-60 (human promyelocytic leukemia) and HT-29 (human colon).

The preliminary tests indicated that betulin (1), betulinic acid (2) and CLA are the most active agents against cancer cell lines studied. However the betulinic acid ester (4) showed comparable activity as CLA.

Fig.1

Fig.2

Acknowledgement: This work was co-financed by the European Union within the European Regional Development Fund (Project no. POIG.01.03.01–00–133/08)

References: 1. Alakurtti S et al. (2006) Eur J Pharm Sci 29: 1–13.

2. Pariza MW et al. (2001) PLipRes 40: 283–298.

3. Hur SJ et al. (2007) Livestock Science 110: 221–229.