The common unsaturated fatty acids present in many vegetable oils (oleic, linoleic and linolenic acids) can be quantitated by 1 H-nuclear magnetic resonance spectroscopy ( 1 H-NMR). A key feature is that the signals of the terminal methyl group of linolenic acid are shifted downfield from the corresponding signals in the other fatty acids, permitting their separate integration and quantitation of linolenic acid. Then, using the integration values of the signals of the allylic and bis-allylic protons, oleic and linoleic acids can be quantitated. The procedure was verified for mixtures of triacylglycerols (vegetable oils) and methyl esters of oleic, linoleic and linolenic acids as well as palmitic and stearic acids. Generally, the NMR (400 MHz) results were in good agreement with gas chromatographic (GC) analyses. As the present 1 H-NMR-based procedure can be applied to neat vegetable oils, the preparation of derivatives for GC would be unnecessary. The present method is extended to quantitating saturated (palmitic and stearic) acids, although in this case the results deviate more strongly from actual values and GC analyses. Alternatives to the iodine value (allylic position equivalents and bisallylic position equivalents) can be derived directly from the integration values of the allylic and bis-allylic protons.

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Gossypol, a complex polyphenolic compound, is a naturally occurring highly colored yellow pigment found in the small intercellular pigment glands in the leaves, stems, roots, and seed of cotton plants. In cottonseed, gossypol contributes to its toxicity and therefore it is regarded as an unwanted processing component. It was not until its antitumor and male infertility activities were discovered that gossypol was considered as a valueadded natural product from cottonseed with useful physiological and chemical properties. These serendipitous discoveries created much excitement, and an enormous amount of research on gossypol has ensued. Since then, much research has focused on the preparation of suitable gossypol derivatives for medicinal applications. This review summarizes current knowledge about gossypol, its stereochemistry, tautomerism, and the many varied reactions the gossypol molecule can undergo.