Cytochalasinols A and B, Two New Cytochalasins From the Fungus Xylaria necrophora SZSS1‐2‐2

Two new cytochalasins ( 1 and 2 ) were isolated from the fermentation products of the fungus Xylaria necrophora SZSS1‐2‐2, along with nine known compounds: compound 3 , arbuschalasin B ( 4 ), cytochalasin C ( 5 ), cytochalasin D ( 6 ), 19,20‐epoxycytochalasin C ( 7 ), 19,20‐epoxycytochalasin D ( 8 ), cytochalasin R ( 9 ), cytochalasin D 13,14‐epoxide ( 10 ), and arbuschalasin A ( 11 ). The structures and absolute configurations of these compounds were elucidated by spectroscopic analyses, electronic circular dichroism, and GIAO 13 C NMR computational methods. All isolated compounds were evaluated for their biological activities, and the results indicated that compounds 5 – 10 exhibited notable cytotoxic effects against the tested cell lines. However, none of the compounds showed antibacterial activity.