Antineoplastic agents. 553. The Texas grasshopper Brachystola magna.

Bioassay (P388 lymphocytic leukemia cell line and human cancer cell lines) guided separation of an extract prepared from the previously chemically uninvestigated Texas grasshopper Brachystola magna led to isolation of the cancer cell growth inhibitory pancratistatin (1), narciclasine (2), and ungeremine (3). Pancratistatin (1) was first isolated from the bulbs of Hymenocallis littoralis), and the original crystal structure was deduced by X-ray analysis of a monomethyl ether derivative. In the present study pancratistatin (1) was isolated from an extract of B. magna, which led to the X-ray crystal structure of this anticancer drug. Since isoquinoline derivatives 1-3 are previously known only as constituents of amaryllidaceous plants, some of the interesting implications of their rediscovery in the grasshopper B. magna that does not appear to utilize amaryllis family plants were discussed.