Two New Cytotoxic Naphthoquinones from Mendoncia cowanii from the Rainforest of Madagascar

 

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Abstract

Bioassay-guided fractionation of the root and stem extracts of Mendoncia cowanii led to the isolation of two new and two known naphthoquinones. The structures of the new compounds, avicequinones D and E (1 and 2), were determined using 1D and 2D NMR spectroscopy and by chemical conversion of compound 1 to 2. The new compounds were active in the A2780 human ovarian cancer cell line with IC₅₀ values of 7.4 - 50 μM, respectively, and 1, 3, and 4 were subsequently found to be weakly active in an assay for inhibition of the kinase Akt.

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Prof. Dr. David G. I. Kingston

Department of Chemistry

M/C 0212

Virginia Polytechnic Institute and State University

Blacksburg

Virginia 24061

U.S.A.

Phone: +1-540-231-6570

Fax: +1-540-231-2355

Email: dkingston@vt.edu