Kabiramides J and K, Trisoxazole Macrolides from the Sponge Pachastrissa nux

Three trisoxazole macrolides possessing a 30-alpha,beta-enone moiety, including the known kabiramide G (1) and the new kabiramides J (2) and K (3), were isolated from the sponge Pachastrissa nux, along with the previously reported kabiramides B (4), C (5), and D (6). To date, the enone moiety has been found to associate solely with the trisoxazole macrolides from P. nux. All of the isolated macrolides showed moderate to strong antimalarial and cytotoxic activities, except for I, which possessed only potent cytotoxicity.