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At least 19 recordsLinked to original sources
PubMed2006

Terpene synthases and the regulation, diversity and biological roles of terpene metabolism.

Terpene synthases are the primary enzymes in the formation of low-molecular-weight terpene metabolites. Rapid progress in the biochemical and molecular analysis of terpene synthases has allowed significant investigations of their evolution, structural and mechanistic properties, and regulation. The organization of terpene synthases in large gene families, their characteristic ability to form multiple products, and their spatial and temporal regulation during development and in response to biotic and abiotic factors contribute to the time-variable formation of a diverse group of terpene metabolites. The structural diversity and complexity of terpenes generates an enormous potential for mediating plant-environment interactions. Engineering the activities of terpene synthases provides opportunities for detailed functional evaluations of terpene metabolites in planta.

Alkyl and Aryl Transferases↗
PubMed2026

A chromosome-scale genome of Capsicum pubescens provides insights into candidate terpene-associated gene clusters and pan variation of terpene synthases.

A chromosome-scale genome of Capsicum pubescens and comparative pan-TPS analysis support structural characterization and gene-level prioritization of a chromosome-9 terpene-associated candidate locus in this accession. Capsicum pubescens is one of the five domesticated Capsicum species, mainly cultivated in mid- to high-elevation regions of the Americas. Despite its distinctive morphology and fruit traits, genomic resources for C. pubescens remain less developed than those for the widely cultivated C. annuum. Here, we assembled a chromosome-scale reference genome for accession HNUCP0001, spanning 3.70 Gb with a scaffold N50 of 278.01 Mb. Comparative genomics revealed 679 significantly expanded gene families enriched in sesquiterpenoid and triterpenoid biosynthesis. Genome-wide biosynthetic gene-cluster mining identified multiple terpene-associated candidate loci, which were subsequently prioritized using genome-derived structural criteria and Capsicum pubescens-specific expression evidence. Subsequently, we curated the terpene synthase (TPS) repertoire and, across 16 Capsicum genomes, resolved 36 TPS orthogroups with pronounced presence/absence variation, highlighting dynamic lineage-specific diversification. Together, these analyses establish HNUCP0001 as an accession-specific genomic resource and provide a comparative framework for prioritizing terpene-associated TPS genes and candidate BGCs in Capsicum. These candidate loci, together with accession-level transcriptomic and metabolomic evidence, offer testable hypotheses for future functional studies of specialized terpenoid metabolism in C. pubescens.

Alkyl and Aryl Transferases↗
PubMed2006

DNA oxidative damage by terpene catechols as analogues of natural terpene quinone methide precursors in the presence of Cu(II) and/or NADH.

Natural terpene quinone methides (QM) and their derivatives have been investigated as therapeutics due to their broad antifungal, antibacterial, and antitumor activities. Recently, we reported that a terpene QM was formed from the catechol precursor through the disproportionation of Cu(II)/(I) redox cycle, and extensive DNA damage was observed throughout the oxidation process. In this paper, we investigate DNA damage with a series of terpene catechols as analogues of natural QM precursors and suggest that reactive oxygen species (ROS) are responsible for the observed DNA damage in the Cu(2+)-induced oxidation despite the stereo- and structural difference of these catechol or subsequent oxidation products. In addition, the presence of NADH significantly enhanced the extent of DNA damage by oxidation of these catechols. Especially with alkene catechols 6-7, the extent of DNA damage was independent of the concentration of catechols, implying that NADH enables the continuous production of ROS through the redox cycle of catechols/quinones.

Base Sequence↗
PubMed2005

[Classification of terpenes and terpene oxides in volatile oil of Fruit of Acanthopanax senticosus (Rupr. Et Maxim) Harms with gas chromatographic retention parameters].

Gas chromatographic (GC) retention parameters (A and B values) for 24 volatile compounds in volatile oil of Acanthopanax senticosus (Rupr. Et Maxim) Harms were obtained from the retention times under five temperature-programming conditions with self-developed GC_AB software based on Levenberg-Marquardt method. The correlation analysis between A and B parameters of terpene and its oxides was carried out. Good linear relationships between A and B parameters were built for seven monoterpenes (C10H16) , nine sesquiterpenes (C15H24), three monoterpene oxides (C10HnO) and three sesquiterpene oxides (C15HnOx) at the same carbon number, respectively. But poor A-B linearity was built for the group formed from monoterpenes and monoterpene oxides or that formed from sesquiterpenes and sesquiterpene oxides at the same carbon number. At the same time the A-B relationships for monoterpenes, sesquiterpenes and their oxides are not collinear. Therefore, this discipline is applied in the assistant identification for terpenes with different carbon numbers and in the classification between terpenes and their oxides. It shows that GC retention parameters calculated from retention times under several temperature-programming conditions are useful for the classification of monoterpenes, sesquiterpenes and their oxides in the analysis of volatile oils from traditional Chinese herbs.

Chromatography, Gas↗
PubMed1962

Microbiological transformations of terpenes. III. Transformations of some mono- and sesqui-terpenes.

The action of Aspergillus niger on mono- and sesqui-terpenic hydrocarbons, such as carane, 3-carene, alpha-santalene, and humulene was studied in shake cultures. Carane, Delta3-carene, and humulene proved to be rather resistant to oxygenation by the experimental strain of A. niger. Carene yielded a hydroxyketone, C(10)H(14)O(2), in poor yields after prolonged fermentation. The sesqui-terpene hydrocarbon, alpha-santalene, was degraded mainly to an acid, tere-santalic acid. Two hydroxylated products were also obtained from alpha-santalene, viz., tere-santalol and an alcohol, C(15)H(24)O.

Alcohols↗
PubMed2003

(E)-beta-ocimene and myrcene synthase genes of floral scent biosynthesis in snapdragon: function and expression of three terpene synthase genes of a new terpene synthase subfamily.

Snapdragon flowers emit two monoterpene olefins, myrcene and (E)-beta-ocimene, derived from geranyl diphosphate, in addition to a major phenylpropanoid floral scent component, methylbenzoate. Emission of these monoterpenes is regulated developmentally and follows diurnal rhythms controlled by a circadian clock. Using a functional genomics approach, we have isolated and characterized three closely related cDNAs from a snapdragon petal-specific library that encode two myrcene synthases (ama1e20 and ama0c15) and an (E)-beta-ocimene synthase (ama0a23). Although the two myrcene synthases are almost identical (98%), except for the N-terminal 13 amino acids, and are catalytically active, yielding a single monoterpene product, myrcene, only ama0c15 is expressed at a high level in flowers and contributes to floral myrcene emission. (E)-beta-Ocimene synthase is highly similar to snapdragon myrcene synthases (92% amino acid identity) and produces predominantly (E)-beta-ocimene (97% of total monoterpene olefin product) with small amounts of (Z)-beta-ocimene and myrcene. These newly isolated snapdragon monoterpene synthases, together with Arabidopsis AtTPS14 (At1g61680), define a new subfamily of the terpene synthase (TPS) family designated the Tps-g group. Members of this new Tps-g group lack the RRx(8)W motif, which is a characteristic feature of the Tps-d and Tps-b monoterpene synthases, suggesting that the reaction mechanism of Tps-g monoterpene synthase product formation does not proceed via an RR-dependent isomerization of geranyl diphosphate to 3S-linalyl diphosphate, as shown previously for limonene cyclase. Analyses of tissue-specific, developmental, and rhythmic expression of these monoterpene synthase genes in snapdragon flowers revealed coordinated regulation of phenylpropanoid and isoprenoid scent production.

Acyclic Monoterpenes↗
PubMed2006

Terpenes and carbohydrate source influence rumen fermentation, digestibility, intake, and preference in sheep.

We hypothesized that toxins and nutrients in foods interact to influence foraging behavior by herbivores. Based on this hypothesis we predicted that 1) terpenes in big sagebrush (Artemisia tridentata) influence intake and preference in sheep for diets varying in sources of nonstructural (barley grain) and structural (sugar beet pulp) carbohydrates, and 2) these effects are due to the differential effects of terpenes on fermentation products and apparent digestibility of each class of carbohydrates. Lambs were fed 2 isoenergetic and isonitrogenous diets with varying proportions of the same ingredients (beet pulp- and barley grain-based diet) or offered a choice between the 2 diets; all feeds were fed without and with terpenes, in consecutive periods. We also compared intake and preference of the beet pulp-and barley-based diets before and after the lambs ate a meal of sagebrush. Finally, we assessed the effect of terpenes on ruminal variables and in vivo digestibility. Lambs ate less when fed beet pulp or when they were offered a choice of diets with terpenes (P < 0.001), and intake of the beet pulp-based diet was the most affected (P < 0.05). Lambs preferred the beet pulp-to the grain-based diet with terpenes, but their preference reversed when terpenes were removed from the diets (P < 0.05). When lambs were offered both diets, intake and preference did not differ (P > 0.20) before eating sagebrush, but they preferred the beet pulp-based diet after eating sagebrush (P < 0.05). Intake of sagebrush did not differ among groups consuming the test diets (P = 0.21). Addition of terpenes to both diets increased the digestibility of DM, NDF, and ADF and decreased concentrations of total VFA and acetate (P < 0.05). Terpenes also depressed butyrate concentration in the barley-based diet (P < 0.05). Propionate concentrations were not affected by terpenes in either feed (P = 0.63). In summary, the predominant type of feed ingredient (beet pulp, grain) ingested with terpenes influenced fermentation products, intake, and preference in lambs. The source of energy from supplements, or other plants in the diet, is likely to influence intake and preference for sagebrush in sheep foraging on rangelands. Moreover, ingesting terpenes from sagebrush may also influence intake and preference for other plant species or supplements.

Animal Feed↗
PubMed2005

Effect of physicochemical properties of cyclic terpenes on their ex vivo skin absorption and elimination kinetics.

BACKGROUND: The terpenes disturb lipid arrangement in the intercellular region of the stratum corneum (SC) that leads to the increased permeability of the skin. This effect is used in technology of transdermal drug forms and depends on physicochemical properties of terpenes and their amounts penetrated to the stratum corneum; however terpenes do not need penetrate into viable skin tissue and this event is not even desired. OBJECTIVE: To correlate skin absorption and elimination kinetics of four cyclic terpenes, namely alpha-pinene, beta-pinene, eucalyptol and terpinen-4-ol, applied as neat substance with their physicochemical properties. METHODS: The terpenes were applied onto the human skin in vitro, and after 1-4 h their content in the separated by a tape-stripping method stratum corneum layers and in the epidermis/dermis was determined using GC. Similarly, the amounts of terpenes in the skin were analysed during 4 h following 1 h absorption. RESULTS: The fastest and progressive penetration into all skin layers was observed for terpinen-4-ol. All studied terpenes are absorbed in the viable epidermis/dermis, however penetration into this layers is time-dependent process, constantly increasing during 4 h. Like for stratum corneum, the largest cumulation in epidermis/dermis was observed for terpinen-4-ol. The elimination of terpenes from the stratum corneum was fast, especially in deeper layers, and much faster if the initial cumulation was small. CONCLUSION: Investigated cyclic terpenes represent different penetration and elimination characteristics and do not permeate across the skin to the acceptor medium due to large cumulation in the skin tissue. The penetration of terpenes into stratum corneum is greater if their log P-value is close to 3.

Adult↗
PubMed1994

Wide-angle X-ray diffraction of human stratum corneum: effects of hydration and terpene enhancer treatment.

Wide-angle X-ray-diffraction experiments were used to investigate the molecular organization of barrier components of human stratum corneum. Diffraction lines related to the side-by-side lipid packing arrangements in the intercellular bilayers were identified as were patterns arising from secondary protein structures in intracellular keratin. Reflections were also identified which may be produced by proteins in the corneocyte envelopes. The effects of hydration on stratum corneum structure were monitored using 0, 20-40, 40-60, 60-80 and approximately 300% hydrated samples. The packing arrangements in the intercellular lipid bilayers remained the same over the entire hydration range, as did keratin structures. A new diffraction ring, attributable to liquid water, was produced by 300% hydrated samples with a repeat spacing of 0.35 to 0.30-0.29 nm. The effects of three terpene enhancers, (+)-limonene, nerolidol and 1,8-cineole, on stratum corneum structure were monitored. Treatment with each of the terpenes produced additional reflections which were attributed to the presence of the respective liquid enhancers within the stratum corneum. (+)-Limonene produced an additional reflection at 0.503-0.489 nm, nerolidol, an additional reflection at 0.486-0.471 nm and 1,8-cineole, an intense reflection at 0.583-0.578 nm. Reflections characteristic of gel-phase lipids and crystalline lipids also remained after all terpene treatments. These results provide no clear evidence of lipid bilayer disruption by the terpenes and suggest that areas of liquid terpene exist within the stratum corneum. The mechanisms underlying propylene glycol synergy with terpene enhancers were investigated. Treatment of stratum corneum with each terpene mixed with propylene glycol gave rise to two additional reflections. One reflection, always positioned at 0.452-0.448 nm, had been observed in control studies following propylene glycol treatment and may have been associated with bilayer structures disrupted by propylene glycol or altered keratin structures. The second reflection was developed by the respective terpene enhancer. For example, treatment with a 1,8-cineole/propylene glycol mixture produced reflections at 0.457-0.451 nm (propylene glycol-disrupted lipids or altered keratin) and 0.591-0.578 nm (liquid 1,8-cineole). Since the reflection at 0.452-0.448 nm was unaffected by co-application of propylene glycol with terpene enhancers, this study offers no evidence to support the theory that propylene glycol synergy with the terpenes occurs through enhanced lipid disruption.

Adult↗