7-oxodehydroabietic Acid Research Articles

Recent advances in understanding resin acid biodegradation: microbial diversity and metabolism.

Resin acids are tricyclic diterpenoids that are found in the oleoresin of coniferous trees. Resin-acid-degrading microorganisms are ubiquitous in the environment. The bacterial isolates that grow on resin acids as sole organic substrates are physiologically and phylogenetically diverse, and include psychrotolerant, mesophilic, and thermophilic bacteria. Recent studies of the biodegradation of resin acids by these organisms have demonstrated that in gram-negative bacteria, distinct biochemical pathways exist for the degradation of abietane- and pimerane-type resin acids. One of these organisms, Pseudomonas abietaniphila BKME-9, harbors a convergent pathway that channels the nonaromatic abietanes and dehydroabietic acid into 7-oxodehydroabietic acid. This dioxygenolytic pathway is encoded by the recently cloned and sequenced dit gene cluster. The dit cluster encodes the ferredoxin and the alpha- and beta-subunits of a new class of ring-hydroxylating dioxygenases as well as an extradiol ring-cleavage dioxygenase. Although it was previously thought that resin acids are very recalcitrant under anoxic conditions, recent investigations have demonstrated that they are partially metabolized under anoxic conditions by undefined microorganisms. The anaerobic degradation of resin acids principally generates aromatized and decarboxylated products (such as retene) that are thought to persist in the environment.

Conjugation of 7-oxodehydroabietic acid to lysine, a haptenation mechanism for an oxidized resin acid with dermal sensitizing properties.

This article explores protein conjugation of 7-oxodehydroabietic acid, a resin acid found in both aerosol from soldering with rosin flux and in rosin solids. In a murine model, conjugation (haptenation) of resin acids to proteins is required to generate antibodies against rosin. Hydroperoxy resin acids are dermal sensitizers, with haptenation thought to occur via radical mechanisms. Dermal sensitization to 7-oxodehydroabietic acid has been observed, although no radical haptenation mechanism has been proposed to explain the sensitizing properties of this compound. Conjugation of L-lysine to 7-oxodehydroabietic acid was predicted, with a Schiff base (or imine) linkage formed between C-7 of the resin acid and a free amino group of lysine. Fast atom bombardment mass spectrometry provided evidence of the conjugate; a small peak was seen for the conjugate (M+H)+ ion in aqueous ethanol with 20 mM concentrations of the free resin and amino acids. A larger conjugate peak was observed with addition of tertiary amine as a mild basic catalyst, and the intensity of the conjugate peak exceeded that of the precursors upon replacement of the ethanol with benzene. Resin acids accumulate in the plasma membrane, a non-aqueous environment apparently conducive to conjugation of 7-oxodehydroabietic acid with lysine side chains of membrane proteins. The result would be dehydroabietic acid covalently bound to protein, which could lead to interaction with immune cells having resin acid specificity. The haptenation mechanism presented may be involved in allergic contact dermatitis and occupational asthma observed from exposure to resin acid solids and aerosols. As sampling and analytical methods have been previously demonstrated for 7-oxodehydroabietic acid, this compound may be a useful exposure marker with relevance to negative health effects such as occupational asthma.

Oxidized Resin Acids in Aerosol Derived from Rosin Core Solder

Exposure to rosin during a variety of uses has been associated with dermal and pulmonary sensitization. Oxidized resin acids are present in many rosin products, and have been regarded as the main sensitizing rosin compounds in cases of dermal sensitization. This research describes oxidized resin acids identified in aerosol produced during soldering with rosin core solder. Oxidized resin acids found were 7-oxodehydroabietic acid, 15-hydroxydehydroabietic acid, and 7-hydroxydehydroabietic acid. The presence of oxidized compounds known to be dermal sensitizers in aerosol from rosin flux soldering supports the hypothesis that resin acid compounds are pulmonary sensitizers as previously proposed. Changes in the composition of resin acid aerosol derived from heated rosin core solder (compared with the parent material) are described.

Oxidized resin acids in aerosol derived from rosin core solder.

Exposure to rosin during a variety of uses has been associated with dermal and pulmonary sensitization. Oxidized resin acids are present in many rosin products, and have been regarded as the main sensitizing rosin compounds in cases of dermal sensitization. This research describes oxidized resin acids identified in aerosol produced during soldering with rosin core solder. Oxidized resin acids found were 7-oxodehydroabietic acid, 15-hydroxydehydroabietic acid, and 7-hydroxydehydroabietic acid. The presence of oxidized compounds known to be dermal sensitizers in aerosol from rosin flux soldering supports the hypothesis that resin acid compounds are pulmonary sensitizers as previously proposed. Changes in the composition of resin acid aerosol derived from heated rosin core solder (compared with the parent material) are described.

Abietane diterpene acids and other constituents from the leaves of Larix kaempferi

The new diterpene acids were isolated from the leaves of Larix kaempferi, together with two known sesquiterpenes, (−)-α-cadinol and oplopanone, and 10 known diterpenes, larixol, dehydroabietinol, 7-oxo-dehydroabietinol, 7-oxodehydroabietic acid, 9α,13α-epidioxyabiet-8(14)-en-18-oic acid, 9β,13β-epidioxyabiet-8(14)-en-18-oic acid, dehydroabietic acid, 7α-hydroxydehydroabietic acid, 8α,9α,13α,14α-diepoxyabietan-18-oic acid and 15-hydroxydehydroabetic acid. The new acids and their methyl esters were characterized as methyl abieta-8,11,13,15-tetraen-18-oic acid, methyl 16- nor-15-oxodehydroabietic acid and methyl 12,15-dihydroxydehydroabietic acid, on the basis of chemical and spectroscopic evidence.

Isolated colophony allergens as screening substances for contact allergy.

Rosin has a complex chemical composition. The aim of this study was to investigate if it is possible to define 1 or 2 compounds as the rosin allergens. 2 compounds, 13, 14(beta)-epoxyabietic acid and 7-oxodehydroabietic acid, identified in gum rosin and tall oil rosin, were used as screening substances for patch testing in addition to the standard series. The rosin patch detected more cases of contact allergy than the isolated allergens did. Our suggestion is to patch test with a preparation of gum rosin, as well-defined as possible, for screening. The content of oxidation products should be kept at a constant and rather high level, since these are the main allergens. A rosin series for additional testing of patients with allergic contact dermatits suspected to be caused by rosin could be a valuable tool. Gum rosin and tall oil rosin from different countries should be included, since the amounts of allergens in rosin varies due to source and mode of production. Testing with identified allergens from modified rosin products and with modified rosins could also be performed.

Acids from blue-stain diseased lodgepole pine

The wood of blue-stain diseased lodgepole pine has been examined for the presence of 2,3-dihydroxybenzoic acid and ceratenolone, compounds believed to be responsible, in the form of their ferric chelates, for the blue coloration of the diseased wood. These compounds were not detected. Dehydroabietic acid, 15-hydroxydehydroabietic acid, 7α- and 7β-hydroxydehydroabietic acid, and 7-oxodehydroabietic acid were isolated. The 1H and 13C nuclear magnetic resonance spectra and mass spectra of the above mentioned compounds are reported.

Contact allergy to dehydroabietic acid derivatives isolated from Portuguese colophony.

7-oxodehydroabietic acid and 15-hydroxydehydroabietic acid were isolated as their methyl esters from Portuguese colophony of the gum rosin type and identified as contact allergens. Another oxidation product of dehydroabietic acid, 15-hydroxy-7-oxodehydroabietic acid, was synthesized and identified as a component of Portuguese gum rosin. 7-oxodehydroabietic acid was found to a be a grade III allergen according to the GPMT method. Guinea pigs induced with gum rosin showed only a low response to the isolated compounds, while patients with a known allergy to gum rosin reacted to a greater extent. The results imply that the content of oxidized dehydroabietic acids in gum rosin is too low to give a marked sensitization in the animals. However, the patients might have come in contact with the allergens in technically modified rosins. The compounds showed a pattern of cross-reactivity in the animal experiments as well as among the patch tested patients.

Electrooxidative Functionalizations of Dehydroabietic Acid

Abstract Dehydroabietic acid methyl ester (1) was converted into 7-acetoxydehydroabietic acid methyl ester by direct electrooxidation in acetic acid and 7-oxodehydroabietic acid methyl ester by ruthenium dioxide-mediated oxidation. Non-Kolbe type electrodecarboxylation of 1 resulted in the introduction of a double bond into the ring A of 1.

Metabolites of the honey mushroom, Armillariamellea

The fungus Armillariamellea (Vahl ex. Fr.) Kummer is responsible for severe losses in timber and fruit production. The metabolites isolated when certain strains of this fungus are grown in liquid culture have been identified as diterpenoid acids possessing the abietane (1) and pimarane (2) skeletons. These compounds, known collectively as resin acids, have not been reported previously from a fungal source. In addition to the resin acids dehydroabietic acid (3), pimaric acid (4), isopimaric acid (5), and sandaracopimaric acid (6), three additional acids, levopimaric acid endo-peroxide (7), 7-oxodehydroabietic acid (9), and 7-oxo-15-hydroxydehydroabietic acid (10) were obtained. On one occasion three orange pigments, austocystin F (11), averufin (12), and averufanin (13), all previously known fungal metabolites, were isolated.

Mutagenicity of resin acids identified in pulp and paper mill effluents using the salmonella/mammalian‐microsome assay

Ten resin acids which have been identified as constituents of pulp and paper mill effluents have been examined for potential mutagenicity in the Salmonella/mammalian-microsome assay. Only neoabietic acid has been found to be mutagenic. Neoabietic acid showed dose-related increases in mutagenicity in strains TA1535, TA100, TA1538, and TA98, but not in strain TA1537. Metabolic activation with a preparation of Aroclor 1254-induced liver homogenate (S9) slightly reduced the mutagenic responses. Negative responses were found for abietic acid, dehydroabietic acid, levopimaric acid, 7-oxodehydroabietic acid, monochlorodehydroabietic acid, dichlorodehydroabietic acid, pimaric acid, isopimaric acid, and sandaracopimaric acid.

Distribution of Some Organic Compounds in the Receiving Waters of a Kraft Pulp and Paper Mill

Water, seston, sediment, and macrophyte samples were collected from Nipigon Bay, Lake Superior at distances up to 6.8 km from the effluent discharge of a kraft pulp and paper mill at Red Rock, Ontario. Fifteen compounds have been identified in mill effluent and six of these were found in samples from the Bay. Mill-related compounds were found most often in water and sediment samples, less often in seston samples, and in none of the macrophytes samples. Dehydroabietic acid, present in mill effluent in excess of 1 mg/ℓ, was found in most water and sediment samples and a few seston samples. This compound is a good indicator of the areal influence of the effluent. Palmitic acid and dioctyl phthalate were also widely distributed. Acetovanillone and sandaracopimaric acid were found in one water sample 1.0 km from the discharge. 7-oxodehydroabietic acid was found in five water samples at distances of up to 4.7 km from the discharge. This is apparently the first time that this compound has been reported in a mill effluent or in environmental samples.