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Planta Med 1999; 65(8): 732-734
DOI: 10.1055/s-1999-14053
Original Paper

Georg Thieme Verlag Stuttgart · New York

Antimycobacterial Ergosterol-5,8-endoperoxide from Ajuga remota

Charles L. Cantrell1 , Mohamed S. Rajab2 , Scott G. Franzblau3 , Frank R. Fronczek1 , Nikolaus H. Fischer1
  • 1 Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana, U.S.A.
  • 2 Department of Chemistry, Moi University, Chepkoilel Campus, Eldoret, Kenya
  • 3 GWL Hansen's Disease Center, Baton Rouge, Louisiana, U.S.A.
Further Information

Publication History

March 9, 1999

April 24, 1999

Publication Date:
31 December 1999 (online)

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Abstract

In a bioassay-guided search for antimycobacterial natural products from higher plants, we have chemically investigated the methanol extract of aerial parts of Ajuga remota Benth. (Labiatae) for its active constituent(s). Bioactive chromatographic fractions of the crude extract provided the known triterpene ergosterol-5,8-endoperoxide plus the diterpenes clerodin, ajugarin-I, and ajugarin-II, which had been previously isolated from A. remota. This is the first report on the isolation of ergosterol-5,8-endoperoxide from this plant. The above compounds were tested in a radiorespirometric bioassay for activity against Mycobacterium tuberculosis. Ergosterol-5,8-endoperoxide showed a minimum inhibitory concentration (MIC) of 1 μg/ml, while ergosterol-5,8-endoperoxide acetate, ergosterol, and ergosta-5,7,9(11),22-tetraen-3β-ol gave MICs of 8 μg/ml, > 128 μg/ml, and 128 μg/ml, respectively. Clerodin, ajugarin-I, and ajugarin-II were inactive with MICs of > 128 μg/ml.

Key words:

Ajuga remota - Labiatae - ergosterol-5,8-endoperoxide - Mycobacterium tuberculosis - antituberculosis - clerodin - ajugarin-I - ajugarin-II

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