A new bioactive diterpenoid from pestalotiopsis adusta, an endophytic fungus from clerodendrum canescens

Abstract

Bioassay-guided fractionation of the culture extract of Pestalotiopsis adusta, an endophytic fungus isolated from the medicinal plant Clerodendrum canescens, led to the isolation of one new, (10S)-12,16-epoxy-17(15→16)-abeo-3,5,8,12,15-abietapentaen-2,7,11,14-tetraone (1), and four known diterpenoids, teuvincenone F (2), uncinatone (3), coleon U (4), coleon U-12-methyl ether (5). These structures were identified by using spectroscopic methods, including UV, MS, 1D and 2D NMR experiments. This is the first report of these compounds being isolated from a Pestalotiopsis species. The cytotoxic activities of the compounds were evaluated, and compounds 1 and 3 demonstrated cytotoxic activities against the HL-60 tumour cell line (IC₅₀ ＜ 20 μM).

Graphical abstract

Keywords:

• Pestalotiopsis adusta
• endophytic fungus
• abietane diterpenes
• cytotoxic activity

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

This work was supported by the Project of Zhejiang Provincial Natural Science Foundation [grant number LQ14C010003], [grant number LQ13C200007]; the Research Foundation of Education Bureau of Zhejiang Province [grant number Y201327898]; the Hangzhou science and technology development plan [grant number 20140432B06].