Cytochalasins from endophytic Diaporthe sp. GDG-118

Abstract

The plant Sophora tonkinensis, possessed a range of active compounds, was traditionally used in the medicine of Chinese minorities. Endophytic fungi were isolated from this plant, of which the fungus Diaporthe sp. GDG-118 was fermented and extracted with methanol. The extract was screened by antifungal and antibacterial assays leading to the discovery of two new 21-acetoxycytochalasins (1–2) and five known cytochalasins (3–7). These two new compounds were elucidated by spectroscopic analyses, and further their absolute configurations were determined by the X-ray of compound 3 and comparing their experimental CD spectra. The antibacterial and antifungal effects of these compounds were evaluated. Compound 2 showed significant inhibitory activity against Bacillus anthraci and Escherichia coli with MIC value of 12.5 μg/mL, and 7 showed strong antifungal activity against Alternaria oleracea, Pestalotiopsis theae and Colletotrichum capsici with MIC values of 3.125, 1.56 and 1.56 μg/mL, respectively.

Keywords:

• Sophora tonkinensis
• Diaporthe sp.
• 21-acetoxycytochalasins
• antibacterial effects
• antifungal effects

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Financial support of this work was provided by the National Natural Science Foundation of China [grant number 21762007], the Guangxi Natural Science Foundation of China [grant number 2018GXNSFAA281169], the Project of State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Guangxi Normal University) [grant number, CMEMR2019-A1, CMEMR2018-C29, CMEMR2016-A06].