Ascosalipyrrolidinone A, an antimicrobial alkaloid, from the obligate marine fungus Ascochyta salicorniae

From the green alga Ulva sp., the endophytic and obligate marine fungus Asc ochyta salicorniae was isolated. A. salicorniae was mass cultivated and fou nd to produce the unprecedented and structurally unusual tetramic acid cont aining metabolites ascosalipyrrolidinones A (1) and B (2). Additionally, th e new natural product ascosalipyrone (3) and the known metabolites 4 and 5 were obtained. Ascosalipyrrolidinone A (1) has antiplasmodial activity towa rd Plasmodium falciparum strains K1 and NF 54, as well as showing antimicro bial activity and inhibiting tyrosine kinase p56(lck).