Search results for "TERPENES"

A Bioinspired Approach to Tri-nor-guaianes. Synthesis of (−)-Clavukerin A

2006

A bioinspired approach to tri-nor-guaianes by degradation of the C-7 side chain of related guaia-11-enes is described. In this approach (-)-clavukerin A (1) is obtained by selective ozonolysis-Criegge rearrangement of (+)-1alphaH,7alphaH,10alphaH-guaia-4,11-dien-3-one (4) to afford 7beta-hydroxy and 7beta-acetoxy tri-nor-guaiane derivatives 6 and 7, respectively, which after elimination and deoxygenation give the title compound. The starting guaiadienone is readily obtained from commercially available santonin or (+)-dihydrocarvone.

In vivo activity of pseudoguaianolide sesquiterpene lactones in acute and chronic inflammation.

2000

The pseudoguaianolide sesquiterpene lactones 4-alpha-O-acetyl-pseudoguaian-6beta-olide (1), hymenin (2), ambrosanolide (3), tetraneurin A (4), parthenin (5), hysterin (6) and confertdiolide (7) were evaluated for their ability to affect the inflammation responses induced by different agents. All the compounds showed activity against the 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced mouse ear edema. The ethyl phenylpropiolate (EPP)-induced mouse ear edema was inhibited by compounds 3, 5 and 7. However, when sesquiterpene-lactones were assayed on the arachidonic acid (AA)-induced mouse ear edema, none of them were active. The only sesquiterpene lactone orally active against the paw mouse…

Minor diterpenoids from Scutellaria polyodon.

2000

Four minor neoclerodane diterpene constituents were isolated from the aerial parts of Scutellaria polyodon. These compounds were characterized as the new scupolins J (1) and K (2) and the previously known scutalpin O (3) and scutalsin.

Sesquiterpenes from Onopordum illyricum and their antifeedant activity

2012

Phytochemical investigation of the acetone extract of the aerial parts of Onopordum illyricum L. afforded five known sesquiterpenoids: compounds 3 and 4 already isolated from O. illirycum, and 8α-[4′-hydroxymethacryloyloxy]-sonchucarpolide (1), 8α-[4′-hydroxymethacryloyloxy]-4-epi-sonchucarpolide (2) and 8-(4′-hydroxymethacryloyl)-dehydromelitensin (5), not previously detected in this species. Compounds 4 and 5 showed moderate antifeedant activity against larvae of Spodoptera littoralis.

Neoclerodane Diterpenoids from Teucrium maghrebinum

2000

Eight neoclerodane diterpenoids were identified in the extract of the aerial parts of Teucrium maghrebinum. Three of these, 12-epi-teucjaponin A (1), 12-epi-montanin D (2), and 12-epi-montanin B (3), are new natural products, whereas five, teucjaponin A, montanin D, 19-deacetylteuscorodol, teusalvin C (4), and montanin B, are already known. These eight compounds form four pairs of epimers at carbon C-12.

Study of the influencing effect of pigments on the photoageing of terpenoid resins used as pictorial media

2006

Abstract Terpenoid resins have been mainly used as components of pictorial varnishes and binding media from ancient times. In such latest instances, the resin is mixed with pigments affecting its physical and chemical properties. A new procedure based on gas chromatography–mass spectrometry (GC/MS) has been applied, in this work, in combination with Fourier transform infrared spectroscopy (FTIR), with the aim of determining the changes undergone by di- and triterpenoid resins employed as components of binding media. The GC/MS method is based on the derivatisation of these resins using trimethylsilylimidazol. Characterization of the main components of the di- and triterpenoid fractions and t…

Evaluation of Biological Effects and Heterogeneous Photodegradation of Terpenes Present in Wastewater From a Citrus Fruit Transformation Factory

2008

Early signaling network in tobacco cells elicited with methyl jasmonate and cyclodextrins.

2012

We analyze, for the first time, the early signal transduction pathways triggered by methyl jasmonate (MJ) and cyclodextrins (CDs) in tobacco (Nicotiana tabacum) cell cultures, paying particular attention to changes in cytosolic free Ca(2+) concentration ([Ca(2+)](cyt)), the production of hydrogen peroxide (H(2)O(2)) and nitric oxide (NO), and late events like the induction of capsidiol. Our data indicate that MJ and CDs trigger a [Ca(2+)](cyt) rise promoted by Ca(2+) influx through Ca(2+)-permeable channels. The joint presence of MJ and CDs provokes a first increase in [Ca(2+)](cyt) similar to that observed in MJ-treated cells, followed by a second peak similar to that found in the presence…

Analysis of the Molecular Dialogue Between Gray Mold (Botrytis cinerea) and Grapevine (Vitis vinifera) Reveals a Clear Shift in Defense Mechanisms Du…

2015

Mature grapevine berries at the harvesting stage (MB) are very susceptible to the gray mold fungus Botrytis cinerea, while veraison berries (VB) are not. We conducted simultaneous microscopic and transcriptomic analyses of the pathogen and the host to investigate the infection process developed by B. cinerea on MB versus VB, and the plant defense mechanisms deployed to stop the fungus spreading. On the pathogen side, our genome-wide transcriptomic data revealed that B. cinerea genes upregulated during infection of MB are enriched in functional categories related to necrotrophy, such as degradation of the plant cell wall, proteolysis, membrane transport, reactive oxygen species (ROS) genera…

Innovative technologies for the recovery of phytochemicals from Stevia rebaudiana Bertoni leaves: A review.

2018

Stevia rebaudiana Bertoni has gained increased industrial and scientific interests in the last 20 years, representing a suitable nutritional alternative to sucrose and artificial sweeteners. Moreover, this plant contains polyphenols, chlorophylls, and carotenoids that may be extracted for production of nutraceuticals and functional foods. Because of nutritional and technological advantages over sucrose, innovative approaches for the extraction of highly valued compounds from Stevia leaves have been developed and optimized. In contrast to conventional alternatives, innovative extraction methods allow higher yields in a shorter time, less usage of organic solvents, and reduced energy consumpt…