Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/13/2006
Publication Date: 4/1/2006
Citation: Dowd, M.K., Pelitire, S.M. 2006. Isolation of 6-methoxy-gossypol and 6,6'-dimethoxy-gossypol from Gossypium barbadense Sea Island cotton. Journal of Agricultural and Food Chemistry. 54(9):3265-3270.
Interpretive Summary: A method was developed to recovery methoxy and dimethoxy-gossypol derivatives from the seeds and roots of Sea Island cotton. Gossypol is a natural product with a wide array of biological activity, including anti-tumor, anti-fertility, anti-fungal and insecticidal effects. The methoxy derivatives of gossypol are found in high concentrations in only a few cotton varieties and are difficult to separate from gossypol. The proposed isolation method should be interest to researchers interested in studying the bioactivity of these compounds.
Technical Abstract: 6-Methoxy-gossypol and 6,6’-dimethoxy-gossypol were isolated from the seed and root bark of a St. Vincent Sea Island variety of cotton (AZK-267, GRIN# PI 528406). A crude preparation of the root bark gossypol fraction was obtained by extraction with acetone and precipitation with acetic acid. After recrystallization, the crude preparation was derivatized with 3-amino-1-propanol to form gossypol Schiff’s bases. The gossypol forms were then separated by preparative reverse-phase chromatography. The recovered Schiff’s bases were hydrolyzed with acid, extracted into diethyl ether, concentrated, and precipitated with acetic acid. Each compound was prepared in sufficient amounts to determine physical properties and begin testing for bioactivity. From the above procedure, each compound was isolated as a solvate of acetic acid in a 1:1 molar ratio. Ultraviolet absorbance differed significantly for the di-3-amino-1-propyl derivatives of gossypol and the two methoxy-gossypol compounds at 254 nm. Relative response factors were developed for each methylated form that can be used for measuring or correcting analytical measurements.