Fatty acids, cyclopropenoid

An acetylenic cyclopropenoid fatty acid, sterculynic acid, is present in the seed lipids of Sterculia alata at a level of about 8% (Jevans and Hopkins, 1968). D-2-Hydroxysterculic acid is found in the seed lipids of Bombacopsis glabra at a level of about 10% (Morris and Hall, 1%7) and, in smaller proportions, in those of various Malvaceae (Bohannon and Kleiman, 1978) (Fig. 2). 

D-2-Hydroxysterculic acid Fig. 2. Structures of less common cyclopropenoid fatty acids. 

Cyclopropanoid and cyclopropenoid fatty acids are often accompanied by epoxy fatty acids (Bohannon and Kleiman, 1978). 

Elucidation of the structures of the various cyclopropanoid fatty acids (Lukina, 1%2 Christie, 1970) and cyclopropenoid fatty acids (Christie, 1970 Carter and Frampton, 1964), and typical reactions of these unusual fatty acids, have been described. Methods for their isolation, identification, and analysis have been discussed as well (Lukina, 1962 Christie, 1970 Carter and Frampton, 1964). Chromatographic methods used in the isolation and analysis of cyclic fatty acids have been described in detail (Lie Ken Jie, 1980). Reference is made to improvements in methods for their characterization and determination by chemical methods (Brown, 1969), spectrophotometry (Coleman and Firestone, 1972), nuclear magnetic resonance (nmr) spectroscopy (Boudreaux et al, 1972 Pawlowski et al., 1972b), mass spectrometry (Eisele et al., 1974), and thermal methods of analysis (White et al., 1976). 

Syntheses of cyclopropanoid fatty acids (Christie and Holman, 1966 Christie et al., 1%8) and cyclopropenoid fatty acids (Gensler et al., 1970 Pawlowski et al., 1972a) have been described. 

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The cyclopropenoid fatty acids, malvaUc acid and stercuhc acid, exist in hexane-defatted meal at levels of 21—76 ppm (70). In rainbow trout, the cyclopropenoid acids cause cancer of the fiver either alone or by acting synergistically with aflatoxin B. However, similar effects in mammals or humans have not been demonstrated (63). 

Studies incorporating cottonseed into many different foods have yielded acceptable products with improved protein quantity and quality. The presence of free gossypol and cyclopropenoid fatty acids (CPFA) potentially limits the use of cottonseed in human foods. 

Cyclopropenoid Fatty Acids. Cottonseed contains cyclopropenoid fatty acids (CPFA) which must be investigated to determine their effects on humans and other monogastric animals. Related to this is the hepatocarcinogenicity of whole kernel glandless cottonseed and cottonseed oil in rainbow trout, Salmo gairdeneri, (22-24). However, the Food and Drug Administration (FDA) has adopted the position that fish are not sufficiently related to man to necessitate the FDA changing its acceptance of cottonseed and its byproducts in human foods (25). 

Cottonseed contains two cyclopropenoid fatty acids, malvalic and sterulic acid. The presence of these two CPFA s could be a limiting factor in the use of cottonseed for human food (26). The preparation of foods containing cottonseed may decrease the amount of cyclopropenoid fatty acids. 

Hardcastle, J. E. Wei, T. F. Reber, E. F. "Cyclopropenoid fatty acid content of food products prepared with cottonseed flour Paper presented at the 187th Annual Meeting of the American Chemical Society, St. Louis, Mo., April, 1984. 

Lee, D.J., Wales, J.H., Ayres, J.L. and Sinnhuber, R.O. Synergism between cyclopropenoid fatty acids and chemical carcinogens in rainbow trout (Salmo gairdneri). Cancer Res. (1968) 28, 2312-2318. 

Wiseman (1986) reported a reduction in digestibility and in available energy of up to 30% due to oxidation of fat as a result of overheating during processing. A number of naturally occurring fatty acids can also adversely affect overall fat utilization. Two such components are erucic acid present in rapeseed oils and some other Brassica spp., and the cyclopropenoid fatty acids present in cottonseed. 

Jeffcoat, R., Pollard, M.R. 1977. Studies on the inhibition of the desaturases by cyclopropenoid fatty acids. Lipids. 12, 480-485. 

Cyclopropenoid Fatty Acids. Cotton, and other plants in the Malvaceae family, contain a pair of unique cyclopropene fatty acids (CPFA). These two fatty acids, sterculic and malvalic acid, are generally referred to collectively as cyclopropenoid fatty acids. Sterculic acid is the most active of the two fatty acids whose general action is to inhibit the desaturation of stearic to oleic fatty acid in the animal body with a resultant alteration in membrane permeability or an increase in the melting point of fats. 

TABLE 9. Cottonseed Oil Cyclopropenoid Fatty Acid Levels. 

Halphen Reaction. The halphen test is a very sensitive and reliable method for detecting the presence of cottonseed oil in another oil. A reaction with sulfur in carbon disulfide mixed with equal amounts of amyl alcohol gives a cherry red color when cyclopropenoid fatty acids unique to the Malvacae family, which includes cottonseed and okra, are present. This test is capable of detecting 0.25% or less cottonseed oil in an oil blend. The oil is no longer responsive to the halphen test after hydrogenation, which decreases the iodine value 2-5 units. 

Other Possible Components. Lipids that might be important as defensive components in cotton are the cyclopropenoid fatty acids (39), hydroxylated unsaturated fatty acids (40), and other oxidation products of unsaturated fatty acids (41). Similar fatty acids are antibiotic and act as self defensiVe compounds in rice (42). Cottonseed oil contains only about 1% each of cyclopropenoidTand hydroxy unsaturated fatty acids. However, oil from immature seeds, radicles (very young roots) and root tips contain high concentrations (up to 28%) of cyclopropenoid acids (39), suggesting a possible protective role for these fatty acids in these tissues. 

Phytochemistry The plant contains mucilage. Leaves contain 165-176 mg% of vitamin C (Khalmatov 1964). The roots contain lipids with cyclopropenoid fatty acids (SagduUaev et al. 2001) and the flowers contain kaempferol glycosides... 

Cyclopropenoid fatty acid UHKJionponaHOH aa actipHaa Epi-rhododendrin 3irapo (o (eimpHH... 

As mentioned above, fatty acids of unusual structure which characterize seed oils from a variety of plants are seldom found in the lipids of the corresponding leaf tissue. However, there are two exceptions to this rule. Firstly, some members of the family Malva accumulate cyclopropenoid fatty acids in their leaves as well as their seeds (Shenstone and Vickery, 1961). Secondly, the y-linolenic and octadecatet-raenoic acids which characterize the seed oils of the Boraginaceae are also found esterified to the leaf lipids (Jamieson and Reid, 1968,1969). 

Methyl Branched, Cyclopropanoid, and Cyclopropenoid Fatty Acids... 

Fig. 2.17. Cyclopropanoid and cyclopropenoid fatty acids from plants.

Cyclopropenoid fatty acids (Fig. 2.17) inhibit fatty acid desaturation in several species, including chicken, rat, pig, cow, and trout, causing a rise in the stearate to oleate ratio. This may have an effect on the composition and function of membranes as variation in lipid composition is known to alter permeability of membrane systems. Numerous types of deleterious effects from consumption of seed oils with cyclopropenoid fatty acids have been observed (Seigler, 1979). A cyclopropene fatty acid from Sterculia foetida oil was lethal to the larvae of Callosobruchus maculatus at 0.1% in artificial diets (Janzen et al., 1977). The most important edible oil with these compounds is cottonseed oil from Gos-sypium hirsutum (Malvaceae). Much of the cyclopropenoid... 

Figure 5.8 Mass spectra (70 eV) of dimethyloxazoline derivatives of A, 9,10-methyleneocta-dec-9-enoic (sterculic) acid B, 2-hydroxy-sterculic acid. Redrawn from Spitzer, V., GC-MS characterization (chemical ionization and electron impact modes) of the methyl esters and oxazoline derivatives of cyclopropenoid fatty acids, J. Am. Oil Chem. Soc., 68(12), 963-9,1991.

Coleman, E. C. (1970) Evaluation of five methods for the quantitative determination of cyclopropenoid fatty acids. J. Offic. Anal. Chem., 53 (6), 1209-13. 

Kint, S., Lundin, R. E., Waiss, A. C. and Elliger, C. A. (1981) Analysis of cyclopropenoid fatty acids by Raman spectroscopy. Anal Biochem., 118, 364-70. 

Nixon, J. E., Eisele, T. A., Wales, J. H. and Sinnhuber, R. O. (1974) Effect of subacute toxic levels of dietary cyclopropenoid fatty acids upon membrane function and fatty acid composition in the rat. Lipids, 9 (5), 314-21. 

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