Indole diketopiperazine alkaloids and aromatic polyketides from the Antarctic fungus Penicillium sp. SCSIO 05705.

A new indole diketopiperazine alkaloid, named penilline D (), together with five known indole alkaloid analogues (-, ), two meroterpenoids ( and ), and four butenolide derivatives (-), were isolated from the Antarctic fungus sp. SCSIO 05705. Extensive spectroscopic analysis and electronic circular dichroism (ECD) calculation were used to elucidate the structure of penilline D (), including its absolute configuration. All isolated compounds (-) were evaluated for their cytotoxic, antibacterial and enzyme inhibitory activities against acetylcholinesterase (AChE) and pancreatic lipase (PL). Among them, compound exhibited moderate in vitro cytotoxic activity against the 143B cell line with IC value of 12.64 ± 0.78 μM. Compound showed strong inhibitory activity against AChE with IC value of 0.36 nM (IC 18.7 nM for Tacrine), while compounds and showed weak PL enzyme inhibitory activity. Furthermore, an in silico molecular docking study was also performed between and AChE.