Planta Med 2004; 70(11): 1058-1063
DOI: 10.1055/s-2004-832647
Original Paper
Biochemistry and Molecular Biology
© Georg Thieme Verlag KG Stuttgart · New York

Effect of 13-epi-Sclareol on the Bacterial Respiratory Chain

Lorena Tapia1 , Janet Torres1 , Leonora Mendoza2 , Alejandro Urzúa3 , Jorge Ferreira4 , Mario Pavani4 , Marcela Wilkens1
  • 1Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Chile
  • 2Departamento de Química de los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Chile
  • 3Laboratorio de Química Ecológica, Facultad de Química y Biología, Universidad de Santiago de Chile, Chile
  • 4Departamento de Bioquímica y Medicina Experimental, Facultad de Medicina, Universidad de Chile, Chile
Weitere Informationen

Publikationsverlauf

Received: February 6, 2004

Accepted: July 10, 2004

Publikationsdatum:
18. November 2004 (online)

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Abstract

13-epi-Sclareol is a labdane-type diterpene isolated from the resinous exudates of the medicinal plant species Pseudognaphalium cheiranthifolium (Lam.) Hilliard et Burtt. and P. heterotrichium (Phil.) A. Anderb. This compound has antibacterial activity only against Gram-positive bacteria, showing a bactericidal and lytic action. The interaction of 13-epi-sclareol with the bacterial respiratory chain was analyzed. The compound inhibited oxygen consumption of intact Gram-positive cells, but not with Gram-negative bacteria. The compound inhibited NADH oxidase and cytochrome c reductase activities, while coenzyme Q reductase and the cytochrome c oxidase activities were not affected. These results suggest that the target site of 13-epi-sclareol is located between coenzyme Q and cytochrome c. Using cytoplasmic membrane fractions, the results of the analysis of the enzyme activities associated with the respiratory chain complexes were the same for both Gram-positive and Gram-negative bacteria, indicating that the compound has no access to the cytoplasmic membrane of intact Gram-negative bacteria. Thus, the Gram-negative envelope may act as a physical barrier that prevents the access of this compound to the site of action.

References

Marcela Wilkens

Facultad de Quimica y Biologia

Universidad de Santiago de Chile

Casilla 40 Correo

33 Santiago

Chile

Telefon: +56-2-681-1366

Fax: +56-2-681-2108

eMail: mwilkens@lauca.usach.cl