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Basis of oleanolic acid antibacterial effect
|Anna M. Grudniak 1, Anna Kurek 1, Anna Klicka 1, Łukasz Samluk 1, Krystyna I. Wolska 1, Ewa Wiktorowska 2, Wirginia Janiszowska 2
1. Uniwersytet Warszawski, Instytut Mikrobiologii, Wydział Biologii, ul. Miecznikowa 1, Warszawa 02-096, Poland
Pentacyclic triterpenoids extracted from a variety of plants have many biological activities which made them useful in medicine and pharmacy. Their antifungal and antiviral effect are well documented. In contrary the data concerning their antibacterial activity are scarce and no cellular target of their action is identified so far. We decided to study the effect of oleanolic acid (OL) obtained from marigold (Calendula officinalis L) on gram-positive and gram-negative bacteria including two pathogenic species – Listeria monocytogenes and Yersinia enterocolitica. We showed that OL preferentially inhibits the growth and survival of gram-positive bacteria. In sublethal concentration OL influences the shape of Escherichia coli and Bacillus megaterium in different way. Escherichia coli cells become longer and B. megaterium much shorter in the presence of this compound. Penicillin bounding proteins, PBPs, which are involved in the bacterial shape determination are not the target of OL activity. OL is also the very potent inhibitor of bacterial sporulation. OL preferentially binds to cell envelope fraction of E. coli but in B. megaterium and L. monocytogenes it was equally distributed between cytoplasm and envelope fractions. We demonstrated that OL enhances lysis of E. coli and L. monocytogenes induced by Triton X and the lysis of B. megaterium induced by Triton X and lysosyme. This compound inhibits lysis in vitro of murein isolated from all tested gram-positive and gram-negative bacteria. OL does not induce stress response as concluded on the basis of its inability to influence the cellular level of DnaK chaperone. Our results suggest that bacterial envelopes can be the potential target of OL activity however the precise mode of its action is not known yet.
This work was supported by founds from the University of Warsaw No BW-1720/22.
Presentation: Poster at Zjazd Polskiego Towarzystwa Biochemicznego, Sympozjum D, by Anna M. Grudniak
See On-line Journal of Zjazd Polskiego Towarzystwa Biochemicznego
Submitted: 2007-04-27 22:58 Revised: 2009-06-07 00:44