Isolation of (-)-gossypol from natural plant.

ABSTRACT

(-)-Gossypol has been isolated from cottonseed of G. barbadense L. Three Gossypium species were studied for the isolation. The study has also revealed a correlation between the optical activity of gossypol isolated and the species of cottonseed used. Gossypol isolated from the species G. barbadense is always found to be levorotatory caused by an excess of (-)-gossypol, whereas that from the species G. hirsutum is always dextrorotatory caused by an excess of (+)-gossypol. Results of most samples (cultivars) showed that optical purity of gossypol isolated from G. barbadense varied from 10-25%, while that from G. hirsutum varied from 10-20%. This is the first report of (-)-gossypol occurring naturally.

ABSTRACT

PIP Both (+ and -)-gossypol and (+)-gossypol have been found to be naturally occurring, while no plant producing (-)-gossypol has to date been located. This study isolated (-)-gossypol from the cottonseed of Gossypium barbadense L. Cottonseed from G hirsutum L and G arboreum L was also investigated. The (-)-gossypol content was consistently higher than the (+) gossypol content for all 16 sample of G barbadense studied, while the (+)-gossypol content was higher in the 10 G hirsutum L samples and the 1 G arboreum L sample. The rotation property of gossypol was mainly correlated with the species of the cottonseed; the area where the cottonseed was cultivated had no effect. Gossypol isolated from G barbadense was always levorotatory as a result of the excess of (-)-gossypol, whereas that from the other 2 species studied was always dextrorotatory due to the excess of (+)-gossypol. The optical purity of gossypol isolated from G barbadense ranged from 10-25%, and that from G hirsutum varied from 10-20%.