Preliminary studies on the chemical properties of the toxic principle from Diamphidia nigroornata larvae, a source of Bushman arrow poison.

The Bushmen of southern Africa use the expressed contents of beetle larvae (Diamphidia, Lebistina and Polyclada species) as arrow poison. an aqueous extract of Diamphidia nigroornata larvae was fractionated by gel filtration on Sephadex G-50. Two fractions were obtained: one (I) of high molecular weight which contains a protein of 60 000 daltons, and a low molecular weight fraction (II) of non-protein nature. Both fractions proved to be lethal to mice: an LD50 of 0.5 - 0.95 (I) and 3.2 - 3.5 (II) mg/kg (intraperitoneal injection), respectively, was determined. The toxic principle of fraction I could be partly separated from the protein by ammonium sulfate precipitation followed by gel filtration. That of fraction II was further resolved into several subfractions by gel filtration of Sephadex G-10; however, the lethal activity was completely lost during purification. In thin-layer chromatography the low molecular weight toxin(s) did not react with reagents for steroids, alkaloids, sugars or terpenes, but showed a positive ninhydrin reaction. It is concluded that the toxic principle of the Bushman arrow poison is a highly labile, low molecular weight compound which is closely attached or bound to a protein protecting it from inactivation.