Tectonaquinones A, B and C: three new naphthoquinone derivatives from the heartwood of Tectona grandis

Abstract

Chemical investigation of the chloroform extract of heartwood of Tectona grandis L. f. led to the isolation of three new naphthoquinone derivatives, tectonaquinones A (1), B (2) and C (3), along with six known compounds: barleriaquinone-I (4), tectoquinone (5), tecomaquinone I (6), lapachol (7), obtusifolin (8) and 2-hydroxy-3-methyl anthraquinone (9). The structures of the new compounds were elucidated by spectroscopic methods including 2 D NMR experiments. Tectonaquinone B is the first natural compound that has a hexa-cyclic dinaphthofuran-dione scaffold. Tectonaquinone C has a bicyclic acetal motif that is unusual in nature.

Graphical Abstract

Keywords:

• Tectonaquinones
• Tectona grandis
• naphthoquinone dimer
• Lamiaceae
• heartwood

Acknowledgement

We gratefully acknowledge Prof. Shuichiro Murakami, School of Agriculture, Meiji University for the antimicrobial assay.

Disclosure statement

No potential conflict of interest was reported by the authors.