HPLC isolation of the sesquiterpene hydrocarbon germacrene B from lime peel oil and its characterization as an important flavor impact constituent

Clark, Benjamin C.; Chamblee, Theresa S.; Iacobucci, Guillermo A.

doi:10.1021/jf00076a019

Cited by 43 publications

(23 citation statements)

References 8 publications

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“…Although retention times of the standard on two different columns (Alltech AT-1000 and Hewlett Packard 5MS) exactly matched those of the putative germacrene B, the mass spectrum matched ␥-elemene. This apparent spectral match was noted by earlier workers (25); however, the retention time of ␥-elemene is much shorter than that of germacrene B. ␥-Elemene has been reported from Lycopersicon (4, 6, 7) but was not found in either Better Boy or VFNT Cherry.…”

Section: Resultssupporting

confidence: 85%

Germacrene C synthase fromLycopersicon esculentumcv. VFNT Cherry tomato: cDNA isolation, characterization, and bacterial expression of the multiple product sesquiterpene cyclase

Colby

Crock

Dowdle-Rizzo

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

121

100

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Germacrene C was found by GC-MS and NMR analysis to be the most abundant sesquiterpene in the leaf oil of Lycopersicon esculentum cv. VFNT Cherry, with lesser amounts of germacrene A, guaia-6,9-diene, germacrene B, ␤-caryophyllene, ␣-humulene, and germacrene D. Soluble enzyme preparations from leaves catalyzed the divalent metal ion-dependent cyclization of [1-3 H]farnesyl diphosphate to these same sesquiterpene olefins, as determined by radio-GC. To obtain a germacrene synthase cDNA, a set of degenerate primers was constructed based on conserved amino acid sequences of related terpenoid cyclases. With cDNA prepared from leaf epidermis-enriched mRNA, these primers amplified a 767-bp fragment that was used as a hybridization probe to screen the cDNA library. Thirty-one clones were evaluated for functional expression of terpenoid cyclase activity in Escherichia coli by using labeled geranyl, farnesyl, and geranylgeranyl diphosphates as substrates. Nine cDNA isolates expressed sesquiterpene synthase activity, and GC-MS analysis of the products identified germacrene C with smaller amounts of germacrene A, B, and D. None of the expressed proteins was active with geranylgeranyl diphosphate; however, one truncated protein converted geranyl diphosphate to the monoterpene limonene. The cDNA inserts specify a deduced polypeptide of 548 amino acids (M r ‫؍‬ 64,114), and sequence comparison with other plant sesquiterpene cyclases indicates that germacrene C synthase most closely resembles cotton ␦-cadinene synthase (50% identity).

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Section: Resultssupporting

confidence: 85%

Germacrene C synthase fromLycopersicon esculentumcv. VFNT Cherry tomato: cDNA isolation, characterization, and bacterial expression of the multiple product sesquiterpene cyclase

Colby

Crock

Dowdle-Rizzo

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

121

100

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“…Other non-volatile compounds found in the TIC for extracted lime oil (5-methoxypsoralen RI = 1994, 5,8-dimethoxy-psoralen RI = 2157) were found to make no contribution to the overall aroma of the oil. In agreement with earlier work, 26 germacrene B was detected and caryophyllene oxide was also found, which were the only odour-active sesquiterpenes that were positively identified, although many odour-active compounds were detected in the region RI = 1300-1650, where most sesquiterpenes elute. These compounds had odours described as woody, spicy, sawdust, and contribute 2.5-3.5% to the aroma of the extracted oil.…”

Section: Extracted Oilsupporting

confidence: 92%

“…Humulene oxide was also found in higher concentrations than in other lime oil samples. Decomposition of sesquiterpenes and the formation so artifacts during gas chromatography have been reported, 10,13,14,26 and we found some significant differences in the TICs Table 6. Odourants eluting in the range RI = 1800-2250 (Supelcowax) found in distilled key lime oil Only odourants detected in both the extracted and distilled samples are shown.…”

Section: Analysis Of Sesquiterpene Odourantssupporting

confidence: 53%

“…19,21,22,24 The odour of some sesquiterpenes has been recorded, 6,25 but their contribution to citrus aroma has not been determined by GC-O. Germacrene B has been identified as the sweet woody-spicy aroma of cold-pressed key lime oil 26 and humulene has been found to contribute to hop aroma 24,27 and rambutan fruit. 28 Sesquiterpenes containing oxygen, such as nootkatone and α-and β-sinensal, have been determined to be important odourants in other citrus oils but are not found in lime oils.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of aroma volatiles in key lime essential oils (Citrus aurantifolia Swingle)

Chisholm

Wilson

Gaskey

2003

Flavour & Fragrance J

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The most intense aroma volatiles of extracted and distilled oils from the peels of key lime (Citrus aurantifolia Swingle) were identified using gas chromatography-olfactometry (GC-O) and gas chromatographymass spectrometry (GC-MS). Over 50 odour-active volatiles were detected in the extracted oil, and over 60 in the distilled oil. Geranial, neral and linalool were found to dominate the lime oil aroma in both oils, which accounted for their fresh, floral citrus-like character. Many simple aldehydes contributed to the aroma of the extracted oil, giving it a characteristic lime tone. The distilled oil contained many new odourants, resulting from the acid-catalysed distillation, which imparted woody, musty, spicy and balsamic notes to its aroma. These are C 10 alcohols and ethers and many sesquiterpenes, most of which possess lower odour activity and contribute to the more intense piney aroma of the distilled oil. 7-Methoxycoumarin was found to be one of the more intense odourants in the extracted oil. Caryophyllene oxide and humulene oxide II were found to be major odourants in the distilled oil; their intensities varied with the method of analysis of the oil. They contribute a sawdust-like and skunky odour, respectively, to the distilled lime oil. Many sesquiterpenes were found to possess some odour activity.

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“…Sesquiterpene hydrocarbons accounted for 3.6%. Clack et al 27 characterized germacrene B as an important flavour impact constituent of Key lime cold-pressed oil, but it was not detected in lime species studied by us. The main aliphatic aldehydes were octanal (0.1%), decanal (0.1%) and dodecanal (trace).…”

Section: Limementioning

confidence: 79%

Volatile constituents of Vietnamese pummelo, orange, tangerine and lime peel oils

Tú

Thanh

Une

et al. 2002

Flavour & Fragrance J

111

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The compositions of Vietnamese pummelo (Citrus grandis Osbeck), orange (C. sinensis Osbeck), tangerine (C. reticulata Blanco var. tangerine) and lime (C. limonia Osbeck) peel oil samples have been investigated by GC and GC-MS. The essential oils were extracted by the cold-pressing method. Hydrocarbons, followed by aldehydes and alcohols, were the most abundant compounds in all four kinds of samples. Their percentages, respectively, were >98.7%, >97.6%, >98.6% and >95.4% in hydrocarbons; >0.3%, 0.4%, >0.3% and 1.1% in total aldehydes; 0.2%, 0.5%, 0.4% and 0.7% in alcohols. In Vietnamese pummelo oil, -terpinene was not detected, while terpinolene was detected in small amounts and nootkatone only at a level of <0.05%. Orange oil composition was comparable to that of other sweet orange oils. υ-3-Carene was detected at a level of 0.1%. Tangerine oil is easily distinguished from other citrus oils by its content of various aliphatic aldehydes. Lime oil presented a very different composition from the other oils studied. Its limonene content was substantially lower than that of pummelo, orange and tangerine oils, whereas -terpinene,ˇ-pinene and˛-pinene occurred in higher proportions, moreover, the sesquiterpene hydrocarbon fraction of this oil is qualitatively more complex and quantitatively more abundant than in the other oils.

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HPLC isolation of the sesquiterpene hydrocarbon germacrene B from lime peel oil and its characterization as an important flavor impact constituent

Cited by 43 publications

References 8 publications

Germacrene C synthase fromLycopersicon esculentumcv. VFNT Cherry tomato: cDNA isolation, characterization, and bacterial expression of the multiple product sesquiterpene cyclase

Germacrene C synthase fromLycopersicon esculentumcv. VFNT Cherry tomato: cDNA isolation, characterization, and bacterial expression of the multiple product sesquiterpene cyclase

Characterization of aroma volatiles in key lime essential oils (Citrus aurantifolia Swingle)

Volatile constituents of Vietnamese pummelo, orange, tangerine and lime peel oils

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