Phomachalasins A-D, 26-oxa[16] and [15]cytochalasans produced by Phoma exigua var. exigua, a potential mycoherbicide for Cirsium arvense biocontrol

From the solid and liquid culture of Phoma exigua var. exigua three new 26-oxa[16] and one [15]cytochalasan, named phomachalasin A-D, were isolated and chemically and biologically characterized. They showed no phytotoxic or antimicrobial activity.