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.

Stability assessment of gas mixtures containing terpenes at nominal 5 nmol/mol contained in treated aluminum gas cylinders

Abstract: Studies of climate change increasingly recognize the diverse influences exerted by terpenes in the atmosphere, including roles in particulates, ozone formation, and their oxidizing potential. Measurements of key terpenes suggest atmospheric concentrations ranging from low pmol/mol (parts per trillion) to nmol/mol (parts per billion), depending on location and compound. To accurately establish concentration trends, assess the role of terpenes in atmospheric chemistry, and relate measurement records from many laboratories and researchers, it is essential to have good calibration standards. The feasibility of preparing well-characterized, stable gas cylinder standards for terpenes at the nmol/mol level is not yet well established. Several of the world’s National Metrology Institutes (NMIs) are researching the feasibility of developing primary and secondary reference gas standards at the nmol/mol level for terpenes. The US NMI, the National Institute of Standards and Technology, has prepared several nmol/mol mixtures, in treated aluminum gas cylinders, containing terpenes in dry nitrogen at nominal 5 nmol/mol for stability studies. Overall, 11 terpenes were studied for stability. An initial gas mixture containing nine terpenes, one oxygenate, and six aromatic compounds, including benzene as an internal standard, was prepared. Results for four of the nine terpenes in this initial mixture indicate stability in these treated aluminum gas cylinders for over 6 months and project long term (years) stability. Interesting results were seen for β-pinene, which when using a linear equation rate decline predicts that it will reach a zero concentration level at day 416. At the same time, increases in α-pinene, d-limonene (R-(+)-limonene), and p-cymene were observed, including camphene, a terpene not prepared in the gas mixture, indicating a chemical transformation of β-pinene to these species. Additional mixtures containing combination of either α-pinene, camphor, α-terpinene, and benzene indicate a second-order quadratic rate decline for the α-pinene and α-terpinene, a linear rate decline for camphor, and a second-order quadratic rate increase of camphene.

Transcriptome analysis of terpene chemotypes of Melaleuca alternifolia across different tissues

Abstract: Plant chemotypes or chemical polymorphisms are defined by discrete variation in secondary metabolites within a species. This variation can have consequences for ecological interactions or the human use of plants. Understanding the molecular basis of chemotypic variation can help to explain how variation of plant secondary metabolites is controlled. We explored the transcriptomes of the 3 cardinal terpene chemotypes of Melaleuca alternifolia in young leaves, mature leaves, and stem and compared transcript abundance to variation in the constitutive profile of terpenes. Leaves from chemotype 1 plants (dominated by terpinen-4-ol) show a similar pattern of gene expression when compared to chemotype 5 plants (dominated by 1,8-cineole). Only terpene synthases in young leaves were differentially expressed between these chemotypes, supporting the idea that terpenes are mainly synthetized in young tissue. Chemotype 2 plants (dominated by terpinolene) show a greater degree of differential gene expression compared to the other chemotypes, which might be related to the isolation of plant populations that exhibit this chemotype and the possibility that the terpinolene synthase gene in M. alternifolia was derived by introgression from a closely related species, Melaleuca trichostachya. By using multivariate analyses, we were able to associate terpenes with candidate terpene synthases.

Diterpene constituents of juniperus polycarpos and their antimicrobial and anti-inflammatory activities

Abstract: Activity-directed study of Juniperus polycarpos led to the isolation of active antimicrobial viz., hinokiol, sandaracopimaric acid 4-eniabietic acid, and other minor terpenes in addition to sabinic acid. The antiinflammatory activity of hinokiol was also demonstrated, using carrageenan-induced inflammation_in rats. The structures of the isolated terpenes were determined by 1HNMR, 13CNMR and 2DNMR, APT, DEPT, PND spectra.