Waikikiamides A-C: Complex Diketopiperazine Dimer and Diketopiperazine-Polyketide Hybrids from a Hawaiian Marine Fungal Strain Aspergillus sp. FM242

Waikikiamides A-C (1-3), structurally complex diketopiperazine derivatives, and putative biogenic precursors, (+)-semivioxanthin (4), notoamide F (5), and (-)-notoamide A (6), were isolated from Aspergillus sp. FM242. 1 and 2, bearing a hendecacyclic ring system, represent a novel skeleton. 3 features the first unique heterodimer of two notoamide analogs with an N-O-C bridge. Compounds 1 and 3 exhibit antiproliferative activity with IC50 values in the range of 0.56 to 1.86 μM. The gene clusters mined from the sequenced genome support their putative biosynthetic pathways.Fil: Wang, Fuqian. Wuhan Nº 1 Hospital; China. University of Hawaii at Hilo; Estados UnidosFil: Sarotti, Ariel Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Jiang, Guangde. University of Florida; Estados UnidosFil: Huguet Tapia, José C.. University of Florida; Estados UnidosFil: Zheng, Shao Liang. Harvard University; Estados UnidosFil: Wu, Xiaohua. University of Hawaii at Hilo; Estados UnidosFil: Li, Chunshun. University of Hawaii at Hilo; Estados UnidosFil: Ding, Yousong. University of Florida; Estados UnidosFil: Cao, Shugeng. University Hawaii Cancer Research Center; Estados Unidos. University of Hawaii at Hilo; Estados Unido