Antioxidant CPA-type indole alkaloids produced from the deep-sea derived fungus Aspergillus sp. SCSIO 41024

Abstract

Twelve indole alkaloids, including α-cyclopiazonic acid (CPA) (1), nine 2-oxo indole CPA derivatives (2–10), and two open-ring indole CPA derivatives (11 and 12), were isolated from the fermentation broth of a deep-sea derived fungus Aspergillus sp. SCSIO 41024. Their structures and absolute configurations were elucidated mainly by using extensive NMR spectroscopic, mass spectrometric and single crystal X-ray diffraction analysis. To the best of our knowledge, the crystallographic data of 3 and 7 were firstly reported, and the absolute configuration of 3 was confirmed for the first time by the single crystal X-ray diffraction analysis. Most isolated compounds were tested for their antimicrobial, antitumor and radical scavenging activities. In addition, compounds 1, 2 and 11 showed moderate antioxidative activity against DPPH with IC₅₀ values of 190.1, 31.9, 228.4 μg/mL, respectively.

Graphical Abstract

Keywords:

• Deep-sea derived
• Aspergillus
• indole alkaloid
• cyclopiazonic acid
• antioxidative activity

Acknowledgement

We are grateful to Dr. Z. Xiao, A. Sun, C. Li, Y. Zhang, and X. Ma in the analytical facility at SCSIO for recording spectroscopic data.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China (Nos. 21772210, 81872891 and 41776169), Project from Institution of South China Sea Ecology and Environmental Engineering, CAS (No. ISEE2018PY04), Guangdong MEPP Fund (No. GDOE[2019]A28), Pearl River S&T Nova Program of Guangzhou (No. 201710010136), Guangzhou Science and Technology Project (201804010462).