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Cytotoxic styrylpyrones from Goniothalamus amuyon.

Two new styrylpyrones, (6R,7R,8R)-8-methoxygoniodiol (1) and (6R,7R,8R)-8-chlorogoniodiol (2), together with seven known styrylpyrones and eight other known compounds, were isolated from the leaves and/or stems of Goniothalamus amuyon. The structures of 1 and 2 were elucidated by spectral data interpretation, and the absolute stereochemistry of styrylpyrones in the diol and triol series was confirmed by X-ray crystallographic analysis and CD spectral data. Compound 2 demonstrated significant selective cytotoxicity toward the HONE-1 cancer cell line.

Annonaceae↗

Antimycobacterial Naphthopyrones from Senna obliqua.

Bioactivity-directed fractionation of the methanolic extract of the stem and fruits of Senna obliqua led to the isolation of two known antimycobacterial natural products, quinquangulin (1) and rubrofusarin (2). Both compounds had minimum inhibitory concentrations (MICs) of 12.0 microg/mL against Mycobacteriatuberculosis in radiometric culture. This is the first report of antimycobacterial activity associated with naphthopyrone compounds. Their structures were determined by spectroscopic means including 1D and 2D NMR techniques and further confirmed by X-ray crystallographic analysis.

Antitubercular Agents↗

Synthetic analogues of the microtubule-stabilizing agent (+)-discodermolide: preparation and biological activity.

A series of seven synthetic discodermolide analogues 2-8, which are minor side products generated during the final stages in the synthesis of (+)-discodermolide (1), have been purified and evaluated for in vitro cytotoxicity against A549, P388, MFC-7, NCI/ADR, PANC-1, and VERO cell lines. These synthetic analogues showed a significant variation of cytotoxicity and confirmed the importance of the C-7 hydroxy through C-17 hydroxy molecular fragment for potency. Specifically, these analogues suggested the relevance of the C-11 hydroxyl group, the C-13 double bond, and the C-16 (S) stereochemistry for the potency of (+)-discodermolide. The preparation, purification, structure elucidation, and biological activity of these new analogues are described.

Alkanes↗

A new dimension to the biosynthetic products isolated from the sponge Negombata magnifica.

Latrunculeic acid (3), a novel analogue of latrunculin B (2a), was isolated from the Red Sea sponge Negombata magnifica and characterized. Several known compounds were also isolated, including latrunculin B (2a), 15-methoxylatrunculin B (2b), 16-epi-latrunculin B (4), and latrunculin C (5). In contrast to the other members of the latrunculin family, the novel compound 3 is a polyketide devoid of the normal macrocyclic and thiazolidinone rings present in previously identified members of this family.

Actin Cytoskeleton↗

Simplified isolation procedure and interconversion of the diastereomers of nepetalactone and nepetalactol.

Three nepetalactones were isolated from Nepeta racemosa (mussinii) by traditional methods. An improved method was developed to isolate nepetalactones from N. faassénii. An epimerization procedure was used to prepare the fourth 7S-nepetalactone diastereomer. The cis-fused nepetalactols were prepared by reduction of the corresponding nepetalactones, while the trans-fused nepetalactols were unstable and found to undergo ring-opening reactions yielding iridodials. The characterizations and structural assignments by means of NMR agree with quantum chemical density functional calculations.

Animals↗

Antiinsectan decaturin and oxalicine analogues from Penicillium thiersii.

Three new oxalicine and decaturin analogues (6-8) have been isolated from organic extracts of Penicillium thiersii, along with the known compounds oxalicines A and B. These compounds (4-8) are members of a group of unique natural products containing terpenoid and pyridine moieties. The structures of the new compounds were elucidated by analysis of NMR and MS data. Most of these metabolites exhibit potent antiinsectan activity against the fall armyworm (Spodoptera frugiperda).

Animals↗

Lehualides A-D, metabolites from a Hawaiian sponge of the genus Plakortis.

A collection of an undescribed marine sponge of the genus Plakortis yielded four new "polyketide-derived" metabolites, lehualides A-D (1-4). The structures of compounds 1-4 were elucidated by interpretation of spectral data. Compound 2 demonstrated cytotoxicity against an ovarian cancer cell line, while compound 4 was active against both ovarian cancer and leukemia cell lines.

Animals↗

Phaeochromycins A-E, anti-inflammatory polyketides isolated from the soil actinomycete Streptomyces phaeochromogenes LL-P018.

Five new polyketide metabolites, phaeochromycins A-E (1-5), were isolated from an actinomycete designated Streptomyces phaeochromogenes LL-P018, cultured from a soil sample collected from a riverbank in Westevenger, Germany. Phaeochromycins A and C were found to be weak inhibitors of MAPKAP kinase-2 (IC50 = 39 and 130 microM, respectively). The structures of the compounds were determined by spectroscopic analysis, primarily two-dimensional NMR, and revealed that phaeochromycins A, B, C, and E were octaketides, elaborated from a C4 starter unit, related to shunt products of the actinorhodin pathway, namely, mutactin, dehydromutactin, SEK34b, and BSM1. Phaeochromycin D (4) is an unusual partially cyclized degraded octaketide intermediate.

Anti-Inflammatory Agents↗

Botcinins A, B, C, and D, metabolites produced by Botrytis cinerea, and their antifungal activity against Magnaporthe grisea, a pathogen of rice blast disease.

Four new metabolites, botcinins A-D, were isolated from the culture filtrate of a strain of Botrytis cinerea. Their structures were determined by spectroscopic methods, mainly NMR techniques, molecular modeling, and the modified Mosher's method. They exhibited antifungal activities against Magnaporthegrisea, a pathogen of rice blast disease. Botcinins B and C have a MIC of 12.5 microM, and botcinins A and D are not active below 100 microM.

Antifungal Agents↗

Hispidin derivatives from the mushroom Inonotus xeranticus and their antioxidant activity.

In an effort to identify antioxidants from edible and medicinal mushrooms, three new hispidin derivatives, methylinoscavin A (2), inoscavin B (4), and methylinoscavin B (5), together with the known compounds inoscavin A and phelligridin F, were isolated from the methanolic extract of the fruiting bodies of Inonotus xeranticus. Their structures were determined on the basis of spectroscopic analyses.

Agaricales↗

Botcinins E and F and Botcinolide from Botrytis cinerea and structural revision of botcinolides.

Botcinins E and F were isolated together with the known botcinolide. The structures of botcinins E and F were determined to be 3-O-deacetylbotcinin A (5) and 3-O-deacetyl-2-epi-botcinin A (6), respectively, by spectroscopic methods and chemical conversion. The structure of botcinolide was revised on the basis of spectroscopic data and chemical conversion. Botcinolide was originally reported as a nine-membered lactone (7), but the revised structure is the seco acid of botcinin E (13). Thus botcinolide is renamed botcinic acid, and homobotcinolide is renamed botcineric acid. Reinvestigation of the spectroscopic data reported for all botcinolide analogues indicates that 4-O-methylbotcinolide and 3-O-acetyl-2-epibotcinolide are the same as a methyl ester of botcinic acid (13a) and botcinin A (1), respectively, and that 2-epibotcinolide may be the same as botcinin E (5). Compounds 5, 6, and 13 showed weak antifungal activity against Magnaporthe grisea, a pathogen of rice blast disease.

Botrytis↗

Goniotriol from Goniothalamus giganteus.

The known styrylpyrone, goniotriol, has been isolated from Goniothalamus giganteus. Its bioactivities are reported, and its structure and relative stereochemistry have been determined by X-ray crystallography as 6R-(7R,8R-dihydro-7,8-dihydroxystyryl)-5S,6R-dihydro-5-hydroxy-2-p yrone.

Animals↗

Inhibition of hepatitis B surface antigen secretion on human hepatoma cells. Components from Rubia cordifolia.

The antiviral activity in the roots of Rubia cordifolia was examined, and three naphthohydroquinones, furomollugin (1), mollugin (2), and rubilactone (3), were isolated from it. Compounds 1 and 2 strongly suppressed the secretion of hepatitis B surface antigen (HBsAg), both with IC50 = 2.0 micrograms/mL, in human hepatoma Hep3B cells while having little effect on the viability of the cells. Evaluation of structurally related derivatives of 1 and 2 revealed that a 6-hydroxy group and a pyran or furan ring contribute to this suppressive effect.

Animals↗

10-Epi-olguine from Rabdosia ternifolia.

An unsaturated lactone, 10-epi-olguine (1), has been isolated from Rabdosia ternifolia (D. Don) Hara. The structure was established by spectroscopic and X-ray crystallographic analyses. The compound displayed modest cytotoxicity in several human cancer cell lines.

Antineoplastic Agents, Phytogenic↗

Isolation and characterization of new anti-HIV and cytotoxic leads from plants, marine, and microbial organisms.

New cytotoxic isomalabaricane triterpenes have been isolated from a sponge Stelletta sp. (1-7); anti-HIV pterocarpans (8 and 9) and isoflavanoids (12-16 and 18) were elucidated from two tropical plants in the genus Erythrina; and anti-HIV enniatins (20 and 22-23) were characterized from fungi in the genera Fusarium and Alternaria. The enniatins were evaluated for in vivo anti-HIV activity in the hollow fiber assay.

Alternaria↗

New phomopsolides from a Penicillium sp.

Investigation of the bioactive compounds from a Penicillium sp. isolated from the inner bark of the Pacific yew, Taxus brevifolia, led to the isolation of the known furanone 1, and a series of phomopsolides. The phomopsolide fractions contained phomopsolides A and B, which have previously been described, and three new phomopsolides. The structures of the new phomopsolides were deduced by comparison of their NMR spectra to those of the known compounds.

Anti-Bacterial Agents↗