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.

Foliar Terpene Chemotypes and Herbivory Determine Variation in Plant Volatile Emissions

Abstract: Plants that synthesize and store terpenes in specialized cells accumulate large concentrations of these compounds while avoiding autotoxicity. Stored terpenes may influence the quantity and profile of volatile compounds that are emitted into the environment and the subsequent role of those volatiles in mediating the activity of herbivores. The Australian medicinal tea tree, Melaleuca alternifolia, occurs as several distinct terpene chemotypes. We studied the profile of its terpene emissions to understand how variations in stored foliar terpenes influenced emissions, both constitutive and when damaged either by herbivores or mechanically. We found that foliar chemistry influenced differences in the composition of terpene emissions, but those emissions were minimal in intact plants. When plants were damaged by herbivores or mechanically, the emissions were greatly increased and the composition corresponded to the constitutive terpenes and the volatility of each compound, suggesting the main origin of emissions is the stored terpenes and not de novo biosynthesized volatiles. However, herbivores modified the composition of the volatile emissions in only one chemotype, probably due to the oxidative metabolism of 1,8-cineole by the beetles. We also tested whether the foliar terpene blend acted as an attractant for the specialized leaf beetles Paropsisterna tigrina and Faex sp. and a parasitoid fly, Anagonia zentae. None of these species responded to extracts of young leaves in an olfactometer, so we found no evidence that these species use plant odor cues for host location in laboratory conditions.

Extraction, Purification, and NMR Analysis of Terpenes from Brown Algae

Abstract: Algal terpenes constitute a wide and well-documented group of marine natural products with structures differing from their terrestrial plant biosynthetic analogues. Amongst macroalgae, brown seaweeds are considered as one of the richest source of biologically and ecologically relevant terpenoids. These metabolites, mostly encountered in algae of the class Phaeophyceae, are mainly diterpenes and meroditerpenes (metabolites of mixed biogenesis characterized by a toluquinol or a toluquinone nucleus linked to a diterpene moiety).In this chapter, we describe analytical processes commonly employed for the isolation and structural characterization of the main terpenoid constituents obtained from organic extracts of brown algae. The successive steps include (1) extraction of lipidic content from algal samples; (2) purification of terpenes by column chromatography and semi-preparative high-performance liquid chromatography; and (3) structure elucidation of the isolated terpenes by means of 1D and 2D nuclear magnetic resonance (NMR). More precisely, we propose a representative methodology which allows the isolation and structural determination of the monocyclic meroditerpene methoxybifurcarenone (MBFC) from the Mediterranean brown alga Cystoseira amentacea var. stricta. This methodology has a large field of applications and can then be extended to terpenes isolated from other species of the family Sargassaceae.

Inhibitory effects of terpene alcohols and aldehydes on growth of green algaChlorella pyrenoidosa.

Abstract: The growth of the green algaChlorella pyrenoidosa was inhibited by terpene alcohols and the terpene aldehyde citral. The strongest activity was shown by citral. Nerol, geraniol, and citronellol also showed pronounced activity. Strong inhibition was linked to acyclic terpenes containing a primary alcohol or aldehyde function. Inhibition appeared to be taking place through the vapor phase rather than by diffusion through the agar medium from the terpene-treated paper disks used in the system. Inhibition through agar diffusion was shown by certain aged samples of terpene hydrocarbons but not by recently purchased samples.

Terpene concentrations and wine quality of Vitis vinifera L. cv. Gewürztraminer as affected by grape maturity and cellar

Abstract: The effect of grape maturity and juice treatments, namely skin-contact and heat treatment, on individual free terpene concentrations in Gewurztraminer juices and wines, as weil as on wine qualjty, was investigated. Total free volatile terpenes and total potentially volatile terpenes were also monitored during ripening of the grapes. Linalool, hotrienol, a -terpineol, citronellol, nerol, geraniol, diendiol-1, trans-geranic acid and the furan linalool oxides were analysed gas chromatographically. Wirre quality characteristics, such as fruitiness/ester-like, spiciness/terpene-like and overall wine quality of the wirres were evaluated sensorially. An increase in grape maturity caused marked increases in total bound terpene, as weil as in most individual terpene concentrations. Skin-contact for 4 and 15 h, respectively, and a combined treatment of 15 h skin-contact and heat treatment caused significant increases in the concentrations of the majority of terpenes analysed. Heat treatment resulted in decreases in geraniol, nerol and citronellol concentrations. The combined skin-contact and heat treatment resulted in higher intensities of fruitiness and spiciness, as weil as overall wine quality.