Search results for "Terpene"
showing 10 items of 816 documents
Two New Triterpene Saponins fromAcanthophyllum laxiusculum
2015
Two new triterpene glycosides, 1 and 2, together with three known ones, were isolated from roots of Acanthophyllum laxiusculum Schiman-Czeika. The structures of the new compounds were established by extensive 1D- and 2D-NMR spectroscopic experiments and MS analyses as 23-O-β-D-galactopyranosylgypsogenic acid 28-O-{β-D-glucopyranosyl-(1→2)-6-O-[4-carboxy-3-hydroxy-3-methyl-1-oxobutyl]-β-D-glucopyranosyl-(1→6)}-[β-D-glucopyranosyl-(1→3)]-β-D-galactopyranosyl ester (1) and gypsogenic acid 28-O-{β-D-glucopyranosyl-(1→2)-6-O-[4-carboxy-3-hydroxy-3-methyl-1-oxobutyl]-β-D-glucopyranosyl-(1→6)}-[β-D-glucopyranosyl-(1→3)]-β-D-galactopyranosyl ester (2).
New Acylated Preatroxigenin Saponins from Atroxima congolana
2003
Eight new acylated preatroxigenin saponins 1–8 were isolated as four inseparable mixtures of the trans- and cis-4-methoxycinnamoyl derivatives, atroximasaponins A1/A2 (1/2), B1/B2 (3/4), C1/C2 (5/6) and D1/D2 (7/8) from the roots of Atroxima congolana. These compounds are the first examples of triterpene saponins containing preatroxigenin (=(2β,3β,4α,22β)-2,3,22,27-tetrahydroxyolean-12-ene-23,28-dioic acid as aglycone. Their structures were elucidated on the basis of extensive 1D- and 2D-NMR studies and FAB-MS as 3-O(β-D-glucopyranosyl)preatroxigenin 28-{O-β-D-xylopyranosyl-(14)-O-α-L-rhamnopyranosyl-(12)-O-[O-β-D-glucopyranosyl-(13)-β-D-glucopyranosyl-(13)]-4-O-(trans-4-methoxycinnamoyl)-β…
Discovery of an Extended Austinoid Biosynthetic Pathway in Aspergillus calidoustus
2017
Filamentous fungi produce a wide range of natural products that are commonly used in various industrial contexts (e.g., pharmaceuticals and insecticides). Meroterpenoids are natural products of interest because of their various biological activities. Among the meroterpenoids, there is a group of insecticidal compounds known as the austinoids. These compounds have also been studied because of their intriguing spiro-lactone ring formation along with various modifications. Here, we present an extension of the original austinol/dehydroaustinol biosynthesis pathway from Aspergillus nidulans in the recently identified filamentous fungus Aspergillus calidoustus. Besides the discovery and elucidati…
Extremely potent antifeedant neo-clerodane derivatives of scutecyprol A
2004
Two known neo-clerodane diterpenoids, scutecyprol A (1) and scutalbin C (2), have been isolated from the acetone extract of the aerial parts of Scutellaria sieberi. The antifeedant activity of scutecyprol A (1), of its 15-oxo derivative (3), and of several halohydrins (4-9), synthesized starting from compounds 1 and 3, against Spodoptera littoralis have been determined and structure-antifeedant relationships are discussed.
Can herbivore-induced volatiles protect plants by increasing the herbivores’ susceptibility to natural pathogens?
2018
In response to insect herbivory, plants mobilize various defenses. Defense responses include the release of herbivore-induced plant volatiles (HIPVs) that can serve as signals to alert undamaged tissues and to attract natural enemies of the herbivores. Some HIPVs can have a direct negative impact on herbivore survival, but it is not well understood by what mechanisms. Here, we tested the hypothesis that exposure to HIPVs renders insects more susceptible to natural pathogens. Exposure of the caterpillars of the noctuid Spodoptera exigua to indole and linalool, but not exposure to (Z)-3-hexenyl acetate, increased the susceptibility to Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV). …
Toxics or Lures? Biological and Behavioral Effects of Plant Essential Oils on Tephritidae Fruit Flies.
2021
The family Tephritidae (Diptera) includes species that are highly invasive and harmful to crops. Due to globalization, international trade, and human displacement, their spread is continuously increasing. Unfortunately, the control of tephritid flies is still closely linked to the use of synthetic insecticides, which are responsible for detrimental effects on the environment and human health. Recently, research is looking for alternative and more eco-friendly tools to be adopted in Integrated Pest Management (IPM) programs. In this regard, essential oils (EOs) and their main compounds represent a promising alternative to chemical insecticides. EOs are made up of phytoconstituents formed fro…
Inhibition of Delayed-Type Hypersensitivity by Cucurbitacin R through the Curbing of Lymphocyte Proliferation and Cytokine Expression by Means of Nuc…
2009
Cucurbitacin R is known to exhibit an anti-inflammatory effect in different experimental models of inflammation. In this article, we outline the effect of cucurbitacin R on T lymphocyte proliferation, cytokine production, and nuclear factor activation, as well as its influence on various experimental models of delayed-type hypersensitivity (DTH) in mice. Cucurbitacin R reduced the proliferation of phytohemagglutinin A-stimulated human T lymphocytes (IC(50), 18 microM), modifying the cell cycle, as well as the production of cytokines [interleukin (IL)-2, IL-4, IL-10, and especially interferon-gamma] and the induction of the principal cyclins implicated in the cell cycle (A(1), B(1), D(2), an…
Structural considerations on the iridoids as anti-inflammatory agents.
1994
Abstract Twelve iridoid glycosides have been evaluated for their anti-inflammatory activity on two models: the carrageenan-induced mouse paw edema and the TPA-induced mouse ear edema. Loganic acid was the most active (44.4% edema inhibition) on the former test, whereas the catalpol derivative mixture isolated from Scrophularia, aucubin, verbenalin, and loganin, showed the highest activity (from 72.0 to 80.0% edema inhibition) on the latter. The results allowed us to establish the relationship between the structure and anti-inflammatory activity on the basis of the different patterns of substitution, particularly hydroxylation, unsaturation, and acylation.
Identification of avarol derivatives as potential antipsoriatic drugs using an in vitro model for keratinocyte growth and differentiation.
2006
Contains fulltext : 49512schalkwijk.pdf (Publisher’s version ) (Closed access) Avarol, a marine sesquiterpenoid hydroquinone, and 14 avarol derivatives have shown interesting anti-inflammatory properties in previous studies. In this study, avarol and derivatives were evaluated in high-throughput keratinocyte culture models using cytokeratin 10 and SKALP/Elafin expression as markers for respectively normal and psoriatic differentiation. Avarol and five of its derivatives (5, 10, 13, 14 and 15) were selected for further study. Only 10, 13, 14 and 15 were able to inhibit keratinocyte cell growth. Changes in expression levels of 22 genes were assessed by quantitative real time PCR (qPCR). From …
Potential Antipsoriatic Avarol Derivatives as Antioxidants and Inhibitors of PGE2 Generation and Proliferation in the HaCaT Cell Line
2004
The synthesis and structure-activity relationships for a series of 14 new avarol derivatives as antioxidants and inhibitors of cell proliferation and PGE(2) generation in human keratinocytes are described. Compound 6 (thiosalicylic derivative) was the most potent inhibitor of superoxide generation in human neutrophils and also potently inhibited PGE(2) generation in the human keratinocyte HaCaT cell line. Compound 7(3'-methylaminoavarone) presented the best antiproliferative profile, by the inhibition of (3)H-thymidine incorporation in HaCaT cells, with potency similar to the reference compound anthralin. None of the avarol derivatives showed any sign of cytotoxicity measured as LDH release…