Trihydroxy fatty acids

Another barnacle species, Elminius modestus, was found to produce mono and trihydroxy fatty acids [146]. Analysis of the extract of whole animal homogenates by TLC provided two hatching factor active bands. The more polar band was tentatively identified as a trihydroxy fatty acid (THFA) band. The less polar band had an / r value similar to a 5-HETE standard. The compounds from this latter band were eluted from the TLC plate, methylated, and trimethylsilylated. GC-MS analysis detected several HEPE s and small amounts of monohydroxy derivatives of Ci8 1, C18 2, and C22 fatty acids. Hydrogenation and subsequent GC-MS analysis allowed identification of the major compound as 8-HEPE (ca. 70%). Five to ten percent of 9-, 11-, and 15-HEPE and minor amounts of 5-, 6-, 12-, and 13-HEPE were also detected. No stereochemical features of these oxylipins were determined. 

In plant tissues, various enzymes convert the hydroperoxides produced by LOX to other products, some of which are important as flavor compounds. These enzymes include hydroperoxide lyase, which catalyzes the formation of aldehydes and oxo acids hydroperoxide-dependent peroxygenase and epoxygenase, which catalyze the formation of epoxy and hydroxy fatty acids, and hydroperoxide isomerase, which catalyzes the formation of epoxyhydroxy fatty acids and trihydroxy fatty acids. LOX produces flavor volatiles similar to those produced during autoxidation, although the relative proportions of the products may vary widely, depending on the specificity of the enzyme and the reaction conditions. 

Additionally, microbial systems convert unsaturated fatty acids to monohydroxy-, dihydroxy- and trihydroxy-fatty acids (Hou, 1995,2000). It is feasible to produce various value-added hydroxy fatty acids and derivatives for industrial applications by exploiting the unique reaction specificities of excep-... 

Since Wallen et al. (1962) reported the first bioconversion of oleic acid to 10-hydroxystearic acid by a Pseudomonad, microbial conversions of unsaturated fatty acids from different substrates by various microbial strains have been widely exploited to produce new, value-added products. Among the unsaturated fatty acids used for microbial production of hydroxy fatty acids, three (oleic, linoleic, and linolenic acids) were well studied as substrates to produce mono-, di-, and trihydroxy fatty acids. Recently, a bacterial strain Pseudomonas aeruginosa NRRL B-18602 (PR3) has been studied to produce hydroxy fatty acids from several fatty acid substrates. In this review, we introduce the production of hydroxy fatty acids from their corresponding fatty acid substrates by P. aeruginosa PR3 and their industrially valuable biological activities. 

There are reports about the production of certain 18 carbon-trihydroxy fatty acids from plants (Baur et al., 1977 Dix and Marnett, 1985 Esterbauer and... 

According to the reports describing metabolic pathways involved in the conversion of linoleic acid to trihydroxy fatty acids, several intermediate reaction products, such as trihydroxy-, hydroperoxy-, dihydroxy-, and hydroxyepoxy-octadecenoate, were involved (Kato et al., 1984,1986). Those metabolites of linoleic acid showed distinct biological functions according to their intermediate structures, including mono-, di-, trihydroxy-octadecenoic acid, and hydroperoxy-, epoxy-forms (Kato et al., 1984 Blair, 2001 Gobel et al., 2002 Hou and Forman, 2000). In an effort to understand the overall mechanism involved in the varied biological functions of the complicated reaction metabolites of bio-converted polyunsaturated fatty acids, Kim et al. (2006) studied the oxidative activities on fish oil, of crude extracts produced by PR3 from... 

Dix,T. A., and Marnett, L. J. 1985. Conversion of linoleic acid hydroperoxide to hydroxy, keto, epoxyhydroxy, and trihydroxy fatty acids by hematin. J. Biol. Chem., 260, 5351-5357. 

Ricinoleic acid (i -12-hydroxy-9-cw-octadecenoic acid) (Fig. 6) accounts for 80-90% of fatty acids in castor oil (from Ricinus communis). It is found in other plant species and in the sclerotia of the ergot fungus Claviceps purpurea). Lesquerolic acid (i -14-hydroxy-ll-cw-eicosenoic acid), which is a C20 homolog of ricinoleic acid, occurs in Lesquerella species (up to 70% of total fatty acids). Isoricinoleic acid (i -9-hydroxy-12-cw-octadecenoic acid, or 9-OH 18 2 12c) is a major acid in the Wrightia species. In plants, several C16 and C18 mono, di, and trihydroxy fatty acids are stmctural components of cutin (a polyester constituent of plant cuticle). 

Scheme 13 Postulated enzymic generation of trihydroxy fatty acids.

Weiss, R.H, J.L. Arnold, and R.W. Estabrook (1987). Transformation of an arachidonic acid hydroperoxide into epoxyhydroxy and trihydroxy fatty acids by liver microsomal cytochrome P-450. Arch. Biochem. Biophys. 252, 334-338. 

Oxygenation of the alkoxyl radical leading to epoxyketo, epoxyhydroxy, and trihydroxy fatty acids... 

The epoxy compounds formed via the peroxygenase reaction may then be hydrolysed by epoxide hydrolases that are an integral part of the peroxygenase pathway, forming di- or trihydroxy fatty acids. This pathway is of importance for plant defence as it is hkely to be involved in the biosynthesis of cutin monomers, in the production of antifungal compounds and in detoxification mechanisms [6]. 

This enzyme oxidizes linoleic and linolenic acids rapidly in whole flour or milling products containing wheat germ or bran mixed with water. The initial hydroperoxides formed by lipoxygenases in stored wheat bran are converted to secondary products, mono- and trihydroxy fatty acids. These oxidation products causing bitter and rancid flavors are formed in higher concentrations in hydrated products than in dry raw materials. Rancid flavors develop rapidly on hydration. 

Liu X-T, Wang Z-Z, Xiao W, Zhao H-W, Yu B (2010) Cholestane glyeosides and trihydroxy fatty acids from the rhizomes of Dioscorea septemloba. Planta Med 76 291-294... 

Of the epoxides produced, the allylic epoxides are known to be particularly susceptible to hydrolysis in the presence of protons. As shown in Fig. 3.32 trihydroxy fatty acids may result from the hydrolysis of an allylic epoxyhydroxy compound. 

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