Inhibition of Human Plasma and Serum Butyrylcholinesterase (EC 3.1.1.8) by {alpha}-Chaconine and {alpha}-Solanine

The purpose of these experiments was to determine the reversibilityof -chaconine and -solanine inhibition of human plasma butyrylcholinesterase(BuChE). For the substrate -naphthylacetate, optimal assay conditionswere 0.50 M sodium phosphate buffer and a substrate concentrationof 3–5 ' 10^–4 M. Dibucaine (1 ' 10^–5 M) indicatedthe usual phenotype for all subjects; -chaconine and -solanineat 2.88 ' 10^–6 M inhibited BuChE about 70 and 50%, respectively.One-and 24-hr incubations at 1 ' 10^–1 M with -chaconine,-solanine, paraoxon, eserine, and ethanol yielded reversibleinhibition with dilution except for paraoxon. Twenty-four-hourdialyses of incubations showed no inhibition except for paraoxon.PAGE enzyme activity gels of 1-and 24-hr incubations also showedno inhibition except for paraoxon. -Chaconine and -solanineare reversible inhibitors of human butyrylcholinesterase. Atestimated tissue levels, -chaconine, -solanine, and solanidineinhibited BuChE 10–86%. In assays which combined -chaconine,-solanine, and solanidine, inhibition of BuChE was less thanadditive. No inhibition of albumin -naphthylacetate esterase(an arylesterase) was noted with any inhibitor. The importanceof these data to adverse toxicological effects of potato alkaloidsis discussed.