Antineoplastic agents. 51. The yellow jacket Vespula pensylvanica.

An ethyl alcohol extract of the yellow jacket Vespula pensylvanica Saussure was found to inhibit growth of the murine P388 lymphocytic leukemia cell line. Separation of a ligroin fraction guided by bioassay led to characterization of the cytotoxic constituents as oleic acid (1a) and palmitoleic acid (1b). Evidence was also found for the presence of palmitic acid and the sterols sitosterol, campesterol and cholesterol.