24 research outputs found
Natural Products from the Lithistida: A Review of the Literature since 2000
Lithistid sponges are known to produce a diverse array of compounds ranging from polyketides, cyclic and linear peptides, alkaloids, pigments, lipids, and sterols. A majority of these structurally complex compounds have very potent and interesting biological activities. It has been a decade since a thorough review has been published that summarizes the literature on the natural products reported from this amazing sponge order. This review provides an update on the current taxonomic classification of the Lithistida, describes structures and biological activities of 131 new natural products, and discusses highlights from the total syntheses of 16 compounds from marine sponges of the Order Lithistida providing a compilation of the literature since the last review published in 2002
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Stereochemical challenges in characterizing nitrogenous spiro-axane sesquiterpenes from the Indo-Pacific sponges Amorphinopsis and Axinyssa
An investigation was conducted to identify the structures and bioactive properties of five compounds isolated from the Halichondrida sponges Amorphinopsis foetida and Axinyssa aplysinoides. All compounds possessed the spiro-axane sesquiterpene core and all were substituted at C-2 with nitrogen containing functionality. The stereochernistry of one known compound has been revised to (2R,5R, 10S)-2-formamido-6-axene (3). It exhibited mild selective solid tumor and mild antibacterial activity and was found from Axinyssa. A second known substance whose stereochemistry has also been revised, (2R,5R, 10S)-2-isothiocyanato-6-axene (4) plus its undescribed diastereomer (5) were isolated from Amorphinopsis. Both sponges were the source of two new N-phenethyl-2-formamido-6-axene diastereomeric compounds 6 and 7. No solid tumor or antibacterial activity was found for 4-7. (c) 2006 Elsevier Ltd. All rights reserved
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Disposition and metabolism of 2′,2′”-Dithiobisbenzanilide in rodents following intravenous and oral administration and dermal application
2',2'''-Dithiobisbenzanilide (DTBBA) is a high-production-volume chemical used as a peptizing agent for rubber. The disposition and metabolism of [14C]DTBBA were determined in male and female rats and mice following oral (4, 40, or 400 mg/kg) and intravenous (IV) (4 mg/kg) administration and dermal application (0.4 or 4 mg/kg). [14C]DTBBA was well absorbed following oral administration (> 60%) and dermal application (∼40-50%) in rats and mice. Following oral administration, the majority of radioactivity was excreted in urine (29 - 70%) and feces (16 - 45%). Unlike rats, mice excreted ∼1-5% of the dose as exhaled CO2. The residual radioactivity in tissues was <1% in both species and sexes. The pattern of disposition following IV administration in male rats was similar to that following oral. When [14C]DTBBA was administered via IV to rats, a significant portion of the dose was recovered in bile (∼13%) suggesting that at least a portion of the dose recovered in feces following oral administration was likely the absorbed dose. The profiles of urine from rats and mice were similar and consisted of four major metabolites and three minor metabolites. The predominant metabolite in urine was the S-glucuronide of the thiol/sulfide cleavage product N-(2-mercaptophenyl)benzamide, which accounted for more than 50% of radioactivity in the radiochromatogram
Carbon Capture and Sequestration: An Exploratory Inhalation Toxicity Assessment of Amine-Trapping Solvents and Their Degradation Products
Carbon
dioxide (CO<sub>2</sub>) absorption with aqueous amine solvents
is a method of carbon capture and sequestration (CCS) from flue gases.
One concern is the possible release of amine solvents and degradation
products into the atmosphere, warranting evaluation of potential pulmonary
effects from inhalation. The CCS amines monoethanolamine (MEA), methyldiethanolamine
(MDEA), and piperazine (PIP) underwent oxidative and CO<sub>2</sub>-mediated degradation for 75 days. C57bl/6N mice were exposed for
7 days by inhalation of 25 ppm neat amine or equivalant concentration
in the degraded mixture. The aqueous solutions were nebulized to create
the inhalation atmospheres. Pulmonary response was measured by changes
in inflammatory cells in bronchoalveolar lavage fluid and cytokine
expression in lung tissue. Ames mutagenicity and CHO-K1 micronucleus
assays were applied to assess genotoxicity. Chemical analysis of the
test atmosphere and liquid revealed complex mixtures, including acids,
aldehydes, and other compounds. Exposure to oxidatively degraded MEA
increased (<i>p</i> < 0.05) total cells, neutrophils,
and lymphocytes compared to control mice and caused inflammatory cytokine
expression (statistical increase at <i>p</i> < 0.05).
MEA and CO<sub>2</sub>-degraded MEA were the only atmospheres to show
statistical (<i>p</i> < 0.05) increase in oxidative stress.
CO<sub>2</sub> degradation resulted in a different composition, less
degradation, and lower observed toxicity (less magnitude and number
of effects) with no genotoxicity. Overall, oxidative degradation of
the amines studied resulted in enhanced toxicity (increased magnitude
and number of effects) compared to the neat chemicals
Disposition and Metabolism of Cumene in F344 Rats and B6C3F1 MiceS⃞
Cumene is a high-production volume chemical that has been shown to be a central nervous system depressant and has been implicated as a long-term exposure carcinogen in experimental animals. The absorption, distribution, metabolism, and excretion of [14C]cumene (isopropylbenzene) was studied in male rats and mice of both sexes after oral or intravenous administration. In both species and sexes, urine accounted for the majority of the excretion (typically ≥70%) by oral and intravenous administration. Enterohepatic circulation of cumene and/or its metabolites was indicated because 37% of the total dose was excreted in bile in bile duct-cannulated rats with little excreted in normal rats. The highest tissue 14C levels in rats were observed in adipose tissue, liver, and kidney with no accumulation observed after repeat dosing up to 7 days. In contrast, mice contained the highest concentrations of 14C at 24 h after dosing in the liver, kidney, and lung, with repeat dosing accumulation of 14C observed in these tissues as well as in the blood, brain, heart, muscle, and spleen. The metabolites in the expired air, urine, bile, and microsomes were characterized with 16 metabolites identified. The volatile organics in the expired air comprised mainly cumene and up to 4% α-methylstyrene. The major urinary and biliary metabolite was 2-phenyl-2-propanol glucuronide, which corresponded with the main microsomal metabolite being 2-phenyl-2-propanol