Antimitotic activity of gossypol and gossypolone

Abstract

Gossypol (8,8′-dicarboxaldehyde, 1,1′,6,6′,7,7′-hexahydroxy, 5,5′-diisopropyl, 3,3′-dimethyl, 2,2′-binaphthalene) was isolated from root bark of Gossypium barbadense L. var. Giza 86. Its 1,4-binaphthoquinone derivative, gossypolone, was prepared by oxidation of gossypol with FeCl3 in acetic acid/acetone. The structures of gossypol and gossypolone were confirmed by physical and spectral data. Their antimitotic activity on Allium cepa L. root tips was investigated. The mitotic rate was markedly decreased after 3, 6 and 24hr of incubation with 500, 250 and 125 ppm gossypol, respectively. With gossypolone, the decrease in mitotic rate was noticed after 6, 12 and 24hr incubation with 500, 250 and 125ppm, respectively. The decrease was irreversible in root tips incubated with 500 and 250 ppm gossy-pol or gossypolone. On the other hand, root tips incubated with 125ppm gossypol or gossypolone regained normal mitotic activity after postincubation in water. Both gossypol and gossypolone markedly decreased the growth rate of Allium cepa L. bulbs in a dose-dependent manner. This assay may be used as an easy and inexpensive method to evaluate the antimitotic potential of agents that could be useful for the treatment of cancer.