Two sesquiterpenoids and a steroid produced by an endophytic fungus Aspergillus sp. YUD20004 and their bioactivity.

Two new sesquiterpenoids asperpenoids A-B (1-2) and one new ergostane-type steroid aspergteroid (3) were isolated from the fungus Aspergillus sp. YUD20004 which was derived from the tuber of Zingiber officinale Roscoe. Their structures and absolute configurations were elucidated by comprehensive spectroscopic analyses, electronic circular dichroism (ECD) spectra and consideration of the biogenetic origins. Especially, asperpenoid A was featured as a rare spiro[6-oxabicyclo[3.2.1]octane-2,2'-oxirane] 5/6/3 tricyclic skeleton. In vitro cytotoxic activity assays, aspergteroid (3) exhibited significant cytotoxic activities against five human cancer cell lines (SMMC-7721, HL-60, A549, SW480 and MDA-MB-231) with IC values ranging from 0.40 to 34.24 μM. Most significantly, compound 3 reduced the viability of SMMC-7721 cells in a concentration-dependent manner with an IC value of 0.40 μM.