linoleic-acid and 1-octen-3-ol

1-Octen-3-ol is a volatile oxylipin found ubiquitously in Basidiomycota and Ascomycota. The biosynthetic pathway forming 1-octen-3-ol from linoleic acid via the linoleic acid 10(S)-hydroperoxide was characterized 40 years ago in mushrooms, yet the enzymes involved are not identified. The dioxygenase 1 and 2 genes (Ccdox1 and Ccdox2) in the mushroom Coprinopsis cinerea contain an N-terminal cyclooxygenase-like heme peroxidase domain and a C-terminal cytochrome P450-related domain. Herein, we show that recombinant CcDOX1 is responsible for dioxygenation of linoleic acid to form the 10(S)-hydroperoxide, the first step in 1-octen-3-ol synthesis, whereas CcDOX2 conceivably forms linoleic acid 8-hydroperoxide. We demonstrate that KO of the Ccdox1 gene suppressed 1-octen-3-ol synthesis, although added linoleic acid 10(S)-hydroperoxide was still efficiently converted. The P450-related domain of CcDOX1 lacks the characteristic Cys heme ligand and the evidence indicates that a second uncharacterized enzyme converts the 10(S)-hydroperoxide to 1-octen-3-ol. Additionally, we determined the gene KO strain (ΔCcdox1) was less attractive to fruit fly larvae, while the feeding behavior of fungus gnats on ΔCcdox1 mycelia showed little difference from that on the mycelia of the WT strain. The proliferation of fungivorous nematodes on ΔCcdox1 mycelia was similar to or slightly worse than that on WT mycelia. Thus, 1-octen-3-ol seems to be an attractive compound involved in emitter-receiver ecological communication in mushrooms.

Topics: Agaricales; Dioxygenases; Ethanol; Heme; Hydrogen Peroxide; Linoleic Acid; Octanols; Oxygenases

This study was investigated the chemical composition of volatile oils and aroma evaluation from the tubers of Apios americana Medikus. Theses volatile oils were obtained by the hydrodistillation (HD) and the solvent-assisted flavor evaporation (SAFE) methods. These oils were analyzed by Gas chromatography (GC), GC-mass spectrometry (GC-MS), GC-olfactometry (GC-O), aroma extract dilution analysis (AEDA) and odor activity values (OAV) for the first time. The major compounds in the HD oil were palmitic acid (36.5%), linoleic acid (10.5%) and nonadecanol (5.7%). Meanwhile, in the SAFE oil, the major compounds were 4-hydroxy-4-methyl-2-pentanone (34.2%), hexanal (11.0%) and hexanol (7.9%). Through aroma evaluation, 20 (HD) and 14 (SAFE) aroma-active compounds were identified by GC-O. As a result, the most intense aroma-active compounds in both extraction methods were 1-octen-3-ol and hexanal, both of which showed high odor activity values (OAV).

Topics: Aldehydes; Distillation; Fabaceae; Fatty Acids; Gas Chromatography-Mass Spectrometry; Indicator Dilution Techniques; Linoleic Acid; Octanols; Odorants; Oils, Volatile; Olfactometry; Palmitic Acid; Plant Oils; Plant Tubers; Volatilization

The volatile oil from Boletopsis leucomelas (Pers.) Fayod was extracted by hydrodistillation with diethylether, and the volatile components of the oil were analyzed by gas chromatography-mass spectrometry. The oil contained 86 components, representing 87.5% of the total oil. The main components of the oil were linoleic acid (15.0%), phenylacetaldehyde (11.2%), and palmitic acid (9.4%). Furthermore, sulfur-containing compounds including 3-thiophenecarboxaldehyde, 2-acetylthiazole, S-methyl methanethiosulfonate, and benzothiazole were detected using gas chromatography-pulsed flame photometric detection. The odor components were evaluated by the odor activity value, and aroma extract dilution analysis was performed through gas chromatography-olfactometry analysis. The oil had a mushroom-like, fatty, and burnt odor. The main components contributing to the mushroom-like and fatty odor were hexanal, nonanal, 1-octen-3-ol, and (2E)-nonenal, while the burnt odor was due to furfuryl alcohol, benzaldehyde, 5-methyl furfural, 2,3,5-trimethylpyrazine, 2-acethylthiazole, and indole.

Topics: Acetaldehyde; Agaricales; Aldehydes; Benzaldehydes; Chromatography, Gas; Furans; Gas Chromatography-Mass Spectrometry; Indoles; Linoleic Acid; Octanols; Odorants; Oils, Volatile; Olfactometry; Palmitic Acid; Photometry; Plant Oils; Plants, Edible; Sulfur Compounds; Volatile Organic Compounds

In this study, the characteristic odorants of the volatile oils from Pleurotus species (P. eryngii var. tuoliensis and P. cystidiosus) were extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS), gas chromatography-olfactometry (GC-O), and aroma extract dilution analysis (AEDA). A total of 52 and 54 components (P. eryngii var. tuoliensis and P. cystidiosus, respectively) were identified, representing about 98.8% and 85.1% of the volatile oils, respectively. The main components of the P. eryngii var. tuoliensis oil were palmitic acid (82, 38.0%), oleic acid (86, 25.0%) and linoleic acid (85, 9.7%). The main components of the P. cystidiosus oil, palmitic acid (82, 25.8%), indole (54, 9.1%) and myristic acid (77, 5.3%). Regarding the aroma components, 16 and 13 components were identified in the P. eryngii var. tuoliensis and P. cystidiosus oils respectively, by the GC-O analyses. The results of the sniffing test, odor activity value (OAV) and flavor dilution (FD) factor indicate that methional, 1-octen-3-ol and nonanal are the main aroma-active components of P. eryngii var. tuoliensis oil. On the other hands, dimethyl trisulfide and 1-octen-3-ol were estimated as the main aroma-active components of the P. cystidiosus oil.

Topics: Aldehydes; Chromatography, Gas; Gas Chromatography-Mass Spectrometry; Indicator Dilution Techniques; Indoles; Linoleic Acid; Myristic Acid; Octanols; Odorants; Oils, Volatile; Oleic Acid; Olfactometry; Palmitic Acid; Pleurotus; Sulfides

1-Octen-3-ol and 10-oxo-trans-8-decenoic acid are metabolites of the breakdown of linoleic acid (LA) by mushroom enzymes. These compounds can be produced in a bioreactor using a crude mushroom homogenate and the exogenous addition of LA and oxygen. The factors' duration of blending, mushroom-buffer ratio, effect of a surfactant, whole against partially clarified reaction broths, purity of LA, and utilization of stumps instead of whole mushrooms were studied for their effect on reaction yield using a 1-L bioreactor. The results showed the feasibility of using the more inexpensive 60%-pure LA instead of the 99%-pure LA even when a yield loss was involved. Waste stumps could be used instead of whole mushrooms with a yield decline of 26%.

Topics: Agaricus; Bioreactors; Linoleic Acid; Linoleic Acids; Octanols; Surface-Active Agents

To analyze and compare the compositions in essential oils from branches and leaves of Rhododendron simsii Planch. and Rhododendron naamkwanense Merr.. Essential oils were extracted by water distillation according to Chinese Pharmacopoeia and analyzed by capillary gas chromatography-mass spectrometry as well as chemometrics resolution method and authentic compounds. The relative contents of each component in the essential oils were obtained by normalization of peak areas.. A total of 124 components were identified, of which 48 compounds were existed in both of the samples. Ninety four compounds accounted for 84.47% of the essential oil from Rhododendron simsii Planch. and seventy eight components accounted for 90.25% of the total essential oil from Rhododendron naamkwanense Merr. were identified. 72.76% and 88.07% of the components in Rhododendron simsii Planch and Rhododendron naamkwanense Merr., respectively, included oxygen element. They are mainly terpenol, acids and esters. 1-octen-3-ol (4.00%, 7.90%), 1,6-octadien-3-ol, 3,7-dimethyl-(12.60%, 3.48%), 9,12,15-octadecatrienoic acid, [Z, Z, Z]- (1.15%, 45.34%), phytol (15.21%, 8.56%), p-menth-1-en-8-ol (2.15%, 3.29%), and 9,12,15-octadecatrienoic acid, ethyl ester, [Z,Z,Z]- (9.16%, 8.01%) were their common main compounds, which accounted for 44. 27% and 76.58% of the total amount of the two essential oil samples, respectively. In addition, n-hexadecanoic acid (7.73%), 9,12-octadecadienoic acid (1.85%) and tetracosanoic acid, methyl ester (1.38%) were also the main compounds in essential oil from Rhododendron simsii Planch.. Much higher reliability and accuracy were obtained with the help of chemometrics resolution method and authentic n-alkane standard solutions than those of using GC-MS alone.

Topics: Linoleic Acid; Octanols; Oils, Volatile; Palmitic Acid; Phytol; Plant Leaves; Plant Oils; Plant Stems; Plants, Medicinal; Rhododendron; Terpenes

In order to confirm the biosynthetic pathway to 1-octen-3-ol from linoleic acid, a crude enzyme solution was prepared from the edible mushroom, Lentinus decadetes. When the reaction was performed in the presence of glutathione peroxidase, which can reduce organic hydroperoxide to the corresponding hydroxide, the amount of 1-octen-3-ol formed from linoleic acid was decreased. At the same time, an accumulation of linoleic acid 10-hydroxide could be detected. The 10-hydroperoxide therefore seems to be an intermediate on the biosynthetic pathway.

Topics: Glutathione Peroxidase; Hydrogen Peroxide; Lentinula; Linoleic Acid; Octanols