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

Twelve indole alkaloids, including α-cyclopiazonic acid (CPA) (), nine 2-oxo indole CPA derivatives (-), and two open-ring indole CPA derivatives ( and ), were isolated from the fermentation broth of a deep-sea derived fungus 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 and were firstly reported, and the absolute configuration of 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 , and showed moderate antioxidative activity against DPPH with IC values of 190.1, 31.9, 228.4 μg/mL, respectively.