Isolation and structure of bryostatins 5–7

Abstract

American (Gulf of Mexico), Mexican (Gulf of California), and Japanese (Gulf of Sagami) specimens of the marine bryozoan Bugulaneritina were found to contain in addition to bryostatin 4 (3a) the new bryostatins 5–7 (3b–d) as major antineoplastic components effective against the murine P388 lymphocytic leukemia. A total of 50 kg of wet B. neritina from the Northeastern Gulf of Mexico led to bryostatins 5–7 in 14.1, 61.9, and 31.2 mg yields respectively. The structural assignments for each of these potentially important substances were derived from detailed interpretation of the 400 MHz ¹H nmr and solution phase secondary ion mass spectral measurements, combined with the results of selective acid-catalyzed hydrolyses.