Leptosphaeric Acid, a Metabolite with a Novel Carbon Skeleton from Leptosphaeria sp. IV403, an Endophytic Fungus in Artemisia annua

Leptosphaeric acid (1), a metabolite with a novel carbon skeleton, was isolated from the AcOEt extract of the culture of Leptosphaeria sp., an endophytic fungus (strain number: IV403) of Artemisia annua. The structure of acid 1 was elucidated on the basis of spectral analyses including homo‐ and heteronuclear correlation NMR experiments (HMQC and HMBC). The absolute configuration of the metabolite was determined by its CD and NOED studies.