Radioimmunoassay for the Quantitative Determination of Catharanthine

Abstract

A radioimmunoassay for the quantitation of pmol amounts of the indole alkaloid catharanthine has been developed. The antiserum was raised against a conjugate of catharanthinic acid-human serum albumin. The measuring range of the assay extends from 0.02 to 20 ng of catharanthine, and as little as 196 fmol may be detected. The antiserum is highly specific for catharanthine showing no cross reactivity with typical Catharanthus alkaloids. This assay allows the rapid, sensitive and precise quantitation of catharanthine in unpurified plant extracts. The distribution of catharanthine in Catharanthus roseus plants and the catharanthine concentration of various Catharanthus species have been investigated. Preliminary experiments indicate that the catharanthine specific radioimmunoassay will be a useful tool in cell culture studies as well.