Crystal structure of the cytotoxic macrocyclic trichothecene Isororidin A

Abstract

The highly cytotoxic macrocyclic trichothecene Isororidin A (C29H40O9) was isolated from the fungus Myrothesium verrucaria endophytic on the wild medicinal plant `Datura' (Datura stramonium L.) and was characterized by one- (1D) and two-dimensional (2D) NMR spectroscopy. The three-dimensional structure of Isororidin A has been confirmed by X-ray crystallography at 0.81 Å resolution from crystals grown in the orthorhombic space group P212121, with one molecule per asymmetric unit. Isororidin A is the epimer of previously described (by X-ray crystallography) Roridin A at position C-13′ of the macrocyclic ring.