Terpene

About: Terpene is a research topic. Over the lifetime, 2208 publications have been published within this topic receiving 51480 citations. The topic is also known as: terpenes.

Analyses of Monoterpenes of Conifers by Gas-Liquid Chromatography

Abstract: Monoterpenes are C10 chemical compounds with carbon skeletons consisting of two isopentane (isoprene) units joined together and are a major component of the steam-volatile part of oleoresin produced in tissues of most conifers. Most of them are monoterpene hydro-carbons (C10H16). But often the volatiles in oleoresin include oxygenated monoterpenes, sesquiterpenes, and n-hydrocarbons and are often studied along with the monoterpene hydrocarbons. In the literature, these chemical are variously termed “monoterpenes”, “terpenes”, “volatile oils”, “essential oils” or “turpentine”. For the chemistry of these compounds see Simonsen and Owen (1953, 1957) and de Mayo (1959).

Volatile Constituents of Mandarin (Citrus reticulata Blanco) Peel Oil from Burundi

Abstract: The essential oil constituents of mandarin (Citrus reticulata Blanco) grown in Burundi were extracted by cold-pressing method and analyzed by GC and GC/MS. Fifty-eight constituents, amounting to 97.2% of the total volatiles were identifed. Monoterpene hydrocarbons accounted for the most abundant chemical group (94.7%). Limonene was the most prominent constituent (84.8%), followed by γ-terpinene (5.4%), myrcene (2.2%) and α-pinene (1.1%). Sesquiterpene hydrocarbons accounted for a minor quantity (0.2%), where germacrene D and valencene were the main constituents. Oxygenated compounds of various chemical groups constituted 2.3%. Aliphatic aldehydes (0.7%) and terpene alcohols (0.7%) were the major chemical groups. The main constituents were linalool (0.7%), octanal (0.5%) and decanal (0.2%). Octyl acetate, α-sinensal, decanol and perillaldehyde occurred at 0.1% levels. Thymol, α-sinensal, methyl thymol, and the acetate esters, bornyl, α-terpinyl, geranyl, citronellyl and decyl acetates were detecte...

Oxidized limonene and oxidized linalool – concomitant contact allergy to common fragrance terpenes

Abstract: BACKGROUND: Limonene and linalool are common fragrance terpenes. Both oxidized R-limonene and oxidized linalool have recently been patch tested in an international setting, showing contact allergy in 5.2% and 6.9% of dermatitis patients, respectively. OBJECTIVE: To investigate concomitant reactions between oxidized R-limonene and oxidized linalool in consecutive dermatitis patients. METHODS: Oxidized R-limonene 3.0% (containing limonene hydroperoxides 0.33%) and oxidized linalool 6% (linalool hydroperoxides 1%) in petrolatum were tested in 2900 consecutive dermatitis patients in Australia, Denmark, Singapore, Spain, Sweden, and the United Kingdom. RESULTS: A total of 281 patients reacted to either oxidized R-limonene or oxidized linalool. Of these, 25% had concomitant reactions to both compounds, whereas 29% reacted only to oxidized R-limonene and 46% only to oxidized linalool. Of the 152 patients reacting to oxidized R-limonene, 46% reacted to oxidized linalool, whereas 35% of the 200 patients reacting to oxidized linalool also reacted to oxidized R-limonene. CONCLUSIONS: The majority of the patients (75%) reacted to only one of the oxidation mixtures, thus supporting the specificity of the reactions. The concomitant reactions to the two fragrance allergens suggest multiple sensitizations, which most likely reflect the exposure to the different fragrance materials in various types of consumer products. This is in accordance with what is generally seen for patch test reactions to fragrance materials.

Volatile Terpene Constituents in Maturing Gewürztraminer Grapes from British Columbia

Abstract: Changes in several physicochemical parameters of grape composition including pH, titratable acidity, soluble solids, weight, color, and phenolic content were examined for Gewurztraminer during ripening. Free and potentially volatile terpenes obtained by distillation were also assessed spectrophotometrically using an acidified vanillin assay and by gas chromatography-mass spectrometry (GC-MS). The colorimetric values of potentially volatile terpenes were estimated to account for nearly 84% of the bound terpenes, and the values of the free volatile terpenes reflected primarily the content of unsaturated aldehydes rather than the free terpenes. A procedure using selected ions specific to terpenes was developed to accelerate the analysis time of GC-MS chromatograms. Based on selected ion chromatograms, higher correlations were found for the bound terpene concentrations in Gewurztraminer vis-a-vis total skin phenolics, skin anthocyanins, and the traditional maturity indices of soluble solids and titratable acidity as compared to free terpene content.

De novo synthesis of high-value plant sesquiterpenoids in yeast.

Abstract: Terpenoids comprise a structurally diverse group of natural products. Despite various and important uses of terpenoids (e.g., flavors, drugs, and nutraceuticals), most of them are, however, still extracted from plant sources, which suffer from high cost and low yield. Alternatively, terpenoids can be produced in microbes using their biosynthetic genes. With the explosion of sequence data, many genes for terpenoid metabolism can be characterized by biochemical approaches and used for the microbial production of terpenoids. However, substrates for in vitro studies of terpene synthases are costly, and the enzymatic synthesis of terpenoids in vitro using recombinant enzymes is insufficient to meet the chemical characterization need. Here, we describe the use of engineered yeast (EPY300) to evaluate in vivo production of sesquiterpenoids. Two sesquiterpene synthase genes (for valencene and 5-epi-aristolochene synthases) were expressed in EPY300 in native and N-terminal thioredoxin fusion forms. By using the thioredoxin fusion, valencene biosynthesis was slightly decreased; however, the production of 5-epi-aristolochene was increased by 10-fold, producing 420 μg mL–1 of 5-epi-aristolochene. Accordingly, the thioredoxin-fused 5-epi-aristolochene was coexpressed with 5-epi-aristolochene dihydroxylase (cytochrome P450 monooxygenase) and its reductase in EPY300. This combinatorial expression yielded hydroxylated sesquiterpene, capsidiol, at ∼ 250 μg mL–1. Detailed experimental procedures and other considerations for this work are given.