Anticholinesterase Activity of Drugs Assayed by a Rapid Colorimetric Method

Publisher Website
Google Scholar
Abstract
A routine colorimetric method is presented for assaying anticholinesterase (antiAChase) activity in pure solutions. It involves measuring the degree to which known amounts of acetylcholine (ACh) are protected from hydrolysis by acetylcholinesterase. ACh is determined after conversion to the hydroxamic acid which is measured spectrophotometrically after complexing with Fe. Color values for various concentrations of ACh are established. The suspected antiAChase is incubated with enzyme and substrate. Alteration in activity of the enzyme is evaluated by comparing the color values so obtained with those found for ACh alone and for ACh plus the enzyme. The method also allows evaluation as to the type of inhibition. At pH 7, 37[degree] C and 0.004 [image] concentration the following compounds were found to be without effect on the enzyme: choline chloride, acetic acid, sodium acetate, acetone, sarcosine, acetamide, betaine ethyl and butyl ester chlorides, gamma-carbethoxypropyl trimethylammonium bromide, atropine, Picrotoxin and Metrazol. Under the same conditions Neostigmine, Carcholin, strychnine, Mecholyl and Papaverine were found to be inhibitors of the enzyme.