Assessment of the anthelmintic activity and toxicity of metabolites of Dalea pogonathera (Fabaceae)

Dalea pogonathera A. Gray was collected as part of a project to determine if metabolites of the genus Dalea have potential for the treatment of human hookworm disease, based on earlier findings of very active materials in D. ornata. We report here the isolation, characterization, and results of ex vivo bioassays of a new chalcone pogonatheridin A (1), and three new prenylated flavanones (3, 6, and 12). The isolated known compounds, a chalcone (2), flavanones (4,5,7-11,13,14), and a flavan-3-ol (15), were also examined. Pogonatheridin A (1) reduced the survival of the adults of Ancylostoma ceylanicum hookworm by 12.5 % (50 μg/mL), while all other compounds showed very weak or no activity. The compounds were tested (50 μg/mL) for toxicity to healthy mammalian cells. Seven of them (2-8) showed > 98 % reduction in survival of splenocytes, while 1 was somewhat less toxic at 74.3 % reduction in survival. While metabolites of D. pogonathera did not show promise as potential anthelmintics for hookworm disease, the toxicity information is of interest, and the rich diversity of metabolites of Dalea spp. remains apparent.