High-performance liquid chromatographic analysis of gossypol

The recent interest in gossypol--a yellow substance occurring in the pigment glands of the seed leaf stem and roots of the cotton plant--has been highlighted by a report that it has a contraceptive action for males in humans and other species e.g. rats rabbits and rhesus monkeys. 1 of the major concerns in conducting research with gossypol is the purity of the chemical used. Gossypol was obtained as gossypol-acetic acid from the Southern Utilization Research Development Division in New Orleans. Stock and standard solutions were freshly made in methanol before use. A prime study objective was to develop a simple analytical high-performance liquid chromatography (HPLC)--a highly sensitive selective and relatively rapid technique to analyze compounds of similar structure--that could be used for the quantitative and qualitative analysis of gossypol. The method was compared with the spectrophotometric procedure that is not used for gossypol determination. The reliability of the 2 procedures was determined by recovery experiments in which the cottonseed samples were fortified with known amounts of standard gossypol. The retention times of standard gossypol and gossypol extracted from cottonseeds were in good agreement. The relationship between the amounts of gossypol injected and the peak areas was linear over at least a 1000-fold range. The gossypol content of cottonseeds using this HPLC method was 0.64 +or- 12% with a recovery of 95.0 +or- 2.1%.