ARS | Publication request: Comparison study of total gossypol and the ratio of its optical isomers in some Uzbek cotton varieties

Submitted to: Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 10, 2009
Publication Date: June 17, 2009
Citation: Uzbekov, V.V., Veshkurova, I.A., Arzanova, I.A., Sultanova, E.M., Salikhov, S.I., Namazov, S.E., Yuldasheva, R.A., Bell, A.A., Stipanovic, R.D. 2009. Comparison study of total gossypol and the ratio of its optical isomers in some Uzbek cotton varieties. Eighth International Symposium on the Chemistry of Natural Compounds, June 15-17, 2009, Eskisehir, Turkey. p55.

Technical Abstract: Cottonseed cake (CSC) can be added to animal feed as a protein source. Uzbekistan produces up to 2.0 million tons of cottonseed annually and approximately 10% of it is used as planting seed for The Republic; the remainder is used for production of CSC and oil. However, these products contain gossypol, a highly-toxic polyphenolic aldehyde. Therefore, CSC is limited to only 5% in animal diets. Gossypol in cottonseed exists in two optically active isomers (enantiomers) called (+)- and (-)-gossypol. Significantly, only (-) gossypol is highly toxic to animals. Parental cotton varieties with a high percentage of (+)-gossypol in the seed provides a new approach to develop new local cultivars of cotton with content of (+)-gossypol above 95%, that may provide cottonseed that may be used in non-ruminant animal feeds. Recently new cotton lines that have a high level of (+)-gossypol in the seed have been derived from "Moco" cottons by U.S. scientists. For the first time in Uzbekistan we have investigated some local commercial and new varieties to determine the total and the percent (+)- to (-)-gossypol in seed. Total gossypol and the ratio of (+)- to (-)-gossypol was determined using HPLC employing a C18-column. For determination of the enantiomer ratio, the seeds were reacted with d-alaninol to provide a diastereomeric mixture of Schiff bases that could be separated by reverse phase chromatography. Thus, we established that the local varieties C-6524, C-6530, and C-6532 have the highest (+)- to (-)-gossypol ratio (>3:2) and lowest total (<2%) gossypol. These accessions will be used to develop new hybrids exhibiting the high (+)-gossypol seed trait. Crosses with some of these varieties and U.S. accessions have been made. Investigations on these hybrids are in progress.