Gossypol, structure

Only a few efforts have been made to evaluate the effects of TA structural variations on toxicity. Methylation decreases toxicity of hemigossypol to Verticillium dahliae (25), of gossypol to rat mast cells (23), and of various TA to HelionTis sod. (22). In contrast, methylaTTon increases the toxicity of various TA"To nematodes (26) and the toxicity of heliocides to rat mast cells ( ). The order of toxicity of different TA to rat mast cells is quinones > heliocides > naphthols > binaphthols (23). Gossypol generally is somewhat more toxic to insects than heliocides, and quinones are least toxic (29,22). 

A number of sesquiterpenes have been demonstrated to have pronounced biological activity ( ) among the non-volatile compounds the sesquiterpene lactones are best known (M) but other oxygenated sesquiterpenes are also known to be active. For example, the role of gossypol, a dimeric sesquiterpene and structurally related compounds has been investigated (21,22). The oxygenated sesquiterpenes, shiromodiol monoacetate and diacetate, from Parabenzoin trilobum (=Lindera triloba Blume) possess potent anti feeding activity toward Spodoptera litura larvae (85). 

Gossypol is chemically reactive due to the reactivity of carbonyl and phenolic hydroxyl groups as well as its bulky binaphthalene structure. Gossypol can react with other compounds to form bound gossypol (BG). In order to better describe the chemical status (forms) of gossypol in cottonseed products, three terms (i.e., FG, BG, and TG) are frequently used. Based on the AOCS (American Oil Chemists Society) official... 

Gossypol is chemically reactive due to the reactivity of its carbonyl and phenolic hydroxyl groups as well as its bulky binaphthalene structure. Therefore, it has been the compound of greatest concern in cottonseed. 

Ibragimov, B. T., Beketov, K. M., Talipov, S. A., and Mardanov, R. G. (1995). X-ray structural investigation of gossypol and its derivatives. XXVIII. Separation of the dilactol tautomeric form of gossypol hexamethyl ether into individual stereoisomers and evaluation of their clathrate-forming capacity. Chem. Nat. Compd. 31, 575-578. 

Phillip, V. A. and Hedin, P. A. (1990). Spectral techniques for the structural analysis of the cotton terpenoid aldehydes gossypol and gossypolone. J. Agric. Food Chem. 38, 525-528. 

Przybylski, P., Kira, J., Schroeder, G., Brzezinski, B., and Bartl, F. (2008a). Molecular structures and stability constants of gossypol and its aza-derivative complexes with silver(I) cations studied by potentiometric, ESI MS, NMR, and AMld semiempirical methods. J. Phys. Chem. A 112, 8061-8069. 

Shelley, M. D., Hartley, L., Groundwater, P. W., and Fish, R. G. (2000). Structure-activity studies on gossypol in tumor cell lines. Anticancer Drugs 11, 209-216. 

Shirley, D. A., Brody, S. S., and Sheehan, W. C. (1957). Structure and reactions of gossypol. V. Methylapogossypol hexamethyl ether and 2, 3-dimethoxy-4-isopropyl-5-allyltoluene. 

Concentrations of constitutive terpenoids in the root epidermis of cotton are unrelated to differences in resistance. But concentrations of terpenoid aldehydes formed in the vicinity of the pericycle, near the head of the animal, act as phytoalexins and are closely correlated with levels of resistance (11, 48). Little or no phytoalexin is formed in the pericycle of susceptible cultivars. Mixtures of terpenoid phytoalexins are more toxic to the nematode than gossypol alone, and mixtures containing methylated terpenoid phytoalexins (from 6. hirsutum) are more toxic than those that contain only nonmethyTated phytoalexins (from 6. arboreum) (49). Thus, the structure of terpenoid phytoalexins also is importan for resistance to root knot nematode. 

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