Extraction of gossypol

The conditions for the extraction of gossypol from cottonseed flakes and from isolated gossypol glands have been investigated. It has been established that the amount of gossypol extracted by hexane is affected mainly by the degree of stirring, the moisture content, the material, and the temperature. By steeping the flakes first with concentrated miscella and then with hexane it is possible to extract about 60–65% of the gossypol. It has been shown that hexane and miscella extract practically no gossypol either from dry or from moistened gossypol glands, and only acetone extracts it almost completely.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 157–160, March–April, 1980.     

Biological activity of gossypol and its derivatives

This review of the literature and of the authors' own investigations is devoted to the biological activity of gossypol and its derivatives. Certain results of the structural—functional analysis of gossypol ethers and the products of its condensation with amines and CH-acids are discussed. The results of pharmacokinetic investigations of radioactively labeled samples of gossypol and its physiologically active derivatives are given.A. S. Sadykov Institute of Bioorganic Chemistry of the Academy of Sciences of the Uzbekistan Republic, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 334–349, May–June, 1993.     

X-ray structural investigation of gossypol and its derivatives XX. Structure of the solvate of gossypol with pyridine

The structure of the solvate of gossypol with pyridine has been determined by x-ray structural analysis. The crystalline solvate is a H-clathrate with the channel type of structure in which there are three pyridine molecules to each host molecule. On the desolvation of gossypol tripyridine, a new polymorph is formed.Communications (XI–XIX) are represented by the publications given in the Literature Cited under Nos. 1–9.Institute of Bioorganic Chemistry, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 186–191, March–April, 1992.     

X-ray investigation of gossypol and its derivatives

The first four homologues of the carboxylic acid series and first two homologues of the monohydric alcohol series with gossypol give equimolar H-clathrates with the channel-type structure that are isostructural with gossypolacetic acid. Formic and acetic acids are capable of forming with gossypol a continuous series of solid substitution solutions. The desolvation of the unstable H-clathrates of carboxylic acids and monohydric alcohols form one and the same polymorph of gossypol. By x-ray structural analysis, the structures have been determined of two complexes of gossypol: an H-clathrate with methanol and a solid solution on the replacement of formic acid by acetic acid in a gossypol matrix.Institute of Bioorganic Chemistry, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 191–197, March–April, 1992.     

X-ray structural investigation of gossypol and its derivatives. XXVII. Structure of the condensation product of gossypol and (−)-α-phenyletiiylamine

The structure of the product of condensation of gossypol with (–)--phenylethylamine has been determined. It has been shown that a possible cause of the difficulty in separating racemic gossypol into optically active components is not a racemization of (–)--phenylethylamine on its condensation with gossypol but the high tendency of gossypol and its derivatives to form dimers.Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 676–681, September–October, 1995. Original article submitted February 6, 1995.     

Accelerated semimicro method of determining the amount of free gossypol in cotton seeds and the products of their processing

A semimicro method is proposed for determining the amount of free gossypol in liquid and solid materials using 70% aqueous acetone as the gossypol extractant.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 608–612, September–October, 1979.     

X-ray structural investigation of gossypol and its derivatives XXII. Structure of the H-clathrate of gossypol with dimethyl sulfoxide

In crystals obtained from solutions in DMSO, gossypol molecules are again present in the aldehyde tautomeric form. These crystals are H-clathrates with the channel type of structure which has much in common with the structure of the complexes of gossypol with methanol and with formic acid.Institute of Bioorganic Chemistry, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 330–334, May–August, 1992.     

Extraction of cottonseed oil

Summary It has been shown that oil of the best quality is obtained on its selective extraction by hexane. Subsequent extraction from the meal of gossypol by 70–80% aqueous, and then dry, acetone permits meal to be obtained with a light cream color containing 0.02% of free gossypol. The omission of dry acetone leads to a darkening of the meal.It has been established that it is possible to achieve a reduction in the consumption of solvents on the direct extraction of cottonseed flake by using weak oil and gossypol miscellas.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 170–173, March–April, 1978.     

X-ray structural investigation of gossypol and its derivatives. IX. Semiclathrates of gossypol with esters of acetic acid

Inclusion compounds of gossypol with a number of acetic acid esters have been obtained and have been identified by derivatography and NMR spectroscopy. An x-ray structural investigation of the structures of crystalline complexes of gossypol with ethyl acetate and butyl acetate has shown that these complexes are isostructural semiclathrates. On the basis of the structures of these two semiclathrates of gossypol, it has been concluded that esters and ketone with chain lengths of from five to seven atoms form inclusion compounds isomorphous with the semiclathrates of ethyl and butyl acetates. If the chain length is shorter or longer than that given, inclusion compounds with a different crystal structure are formed.A. S. Sadykov Institute of Bioorganic Chemistry, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 669–675, September–October, 1988.     

Isolation of gossypol from hexane-acetone miscellas

Summary 1. The influence of the nature of the alkali on the degree of extraction of gossypol from hexane — acetone miscellas by solutions of NH₄OH, borax, sodium carbonate, and caustic soda has been studied. It has been established that the maximum extraction of gossypol is achieved by using 2% caustic soda solution.2. It is proposed to treat the aqueous layer formed in the decomposition of the sodium gossypolate with sodium chloride, which enables the yield of gossypol to be raised to 90%.3. It has been shown that the concentration of the miscella in order to eliminate acetone does not lower the yield of gossypol on its isolation from caustic soda solution.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 177–180, March–April, 1978.     

New gossypol imines

Information is given on new gossypol imines. The use of hydrazines as the imine components produces Schiff bases of gossypol existing in the benzoid form.A. S. Sadykov Institute of Bioorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 62 70 71. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 703–706, September–October, 1997.     

Composition of cottonseed soapstock fats

The compositions of cottonseed soapstocks from first-grade and low-grade cotton seeds have been studied by the methods of CC on polyamide and on silica gel, TLC, GLC, ESR, and UV, IR, and mass spectrometry. It has been found that saturated, and also oxygenated, fatty acids, nonpolar acylglycerols, glycolipids, sterols, arylalkanes, gossypol pigments, and ions of metals of variable valence are concentrated in the acid fat of the soapstock from low-grade seeds. The soapstock contains a very small amount of tocopherols and phospholipids, mainly phosphatidylinositols. The combined gossypol pigments of the soapstocks include stabilized gossypol radical ions.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 502–508, July–August, 1988.     

Transformations of gossypol in low-molecular-mass alcohols

It has been shown that the transformations of gossypol into anhydro derivatives on its storage in methanol, ethanol, and propanol take place the faster the lower the molecular mass of the alcohol and the higher the temperature of the process. It has been established that when alcoholic solutions of gossypol in methanol are heated it is converted completely into dianhydrogossypol, in propanol into monoanhydrogossypol, and in ethanol into a mixture of equal amounts of mono- and dianhydro derivatives.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 712–715, September–October, 1989.     

New azo derivatives of gossypol

New azo derivatives of gossypol are described. Their physicochemical properties are reported. The presence of hydroxyazo- and quinonhydrazo-tautomers is proposed.A. S. Sadykov Institute of Bioorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (99871) 162 70 71. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 145–148, March–April, 2000.     

Imines of gossypol ethers

Imines of methyl ethers of gossypol have been synthesized for the first time, their structures have been shown, and their immunomodulating activities have been determined. The quinoid form of existence of the imines of the dimethyl ether and the benzoid form of the imine of the mexamethyl ether of gossypol have been shown.A. S. Sadykov Institute of Bioorganic Chemistry, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 358–363, May–June, 1991.     

Photodynamic effects in the components of cotton seeds

The formation of a stable radical cation and of an unstable peroxide form of gossypol in the light under aerobic conditions has been established on the basis of an analysis of the ESR spectra obtained. The formation of mono- and dianions of gossypol in its alkaline solutions has been shown.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenni, No. 3, pp. 354–360, May–June, 1987.     

Identification and quantification of gossypol in cotton by using packed micro-tips columns in combination with HPLC

Self-packed micro-tip columns containing a C₁₈-bonded silica stationary phase, based on the same principles as solid-phase extraction methods, were used to obtain gossypol and related sesquiterpenoid aldehyde-enriched fractions. The enriched metabolite fractions were then analyzed by optimized high-performance liquid chromatography (HPLC) with a C₁₈ column (4.6 mm×25 cm) eluted with the binary mobile phase acetonitrile–0.1% aqueous TFA solution (80:20). This method has proven to be highly reproducible. The precision and accuracy, as %RSD and %RME values, were determined to be less than 15% for the method. The minimum detection limit of gossypol was determined to be 10 ng (absolute gossypol). Absolute recovery was greater than 94% with a standard deviation of ±3.68%. This is a simple, fast, and cost-effective method for isolation, identification, and quantification of gossypol and related secondary metabolites. Comparative analysis of gossypol content was performed on different parts of the cotton plant (seeds, stems and leaves) of two different cultivars of Gossypium hirsutum L. (Acala_1517–70 and OR₁₉). The results indicate that the OR₁₉ cv naturally contains higher gossypol levels than the Acala cv. It was also found that treatment of leaves with a Verticillium dahliae-derived elicitor induced production of deoxyhemigossypol rather than gossypol.     

1H and13C NMR spectra of transformation products of gossypol in solutions

The complete cycle of the transformation of gossypol in solutions takes place in the measuring ampul of a NMR spectrometer. It has been established for the first time that, in methanol, gossypol is converted into stereoisomeric dilactol 15,15-dimethyl ethers which change into dianhydrogossypol in chloroform and back into gossypol in aqueous acetone. The¹H and¹³C NMR spectra of the main and intermediate products of the conversion of gossypol in the solvents mentioned have been studied in detail for the first time and a complete assignment of their resonance characteristics has been made. It has been shown that dianhydrogossypol is formed through intermediate stereoisomeric 15,15-dimethyl ethers of the dilactol form of gossypol.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 166–177, March–April, 1990.     

Quantitative estimation of gossypurpurin in the isolation of gossypol

It has been found that the relative amounts of free gossypol contained in the products of the extraction of defatted high-gossypol cottonseed flour by chloroform, diethyl ether, and acetone falls with an increase in the polarity of the solvents. It has been shown that, in addition to gossypol, gossypurpurin is extracted. Its highest amount (4.82%) was found in an acetone extract, and its lowest amount (2.68%) in an ethereal extract.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 716–718, November–December, 1983.