Search results for "analytical"
showing 10 items of 9586 documents
Radioactively labelled epoxides. part V. Tritium labelled K-region oxides and trans-dihydrodiols of pyrene, benzo[a]pyrene and dibenz[a, h]anthracene
1987
Tritium labelled K-region oxides of pyrene, benzo[a]pyrene and dibenz[a,h]anthracene have been prepared by cyclization of the corresponding trans-dihydrodiols which were obtained by reduction of K-region quinones with sodium borotritide in the presence of oxygen. This synthetic pathway not only yields two metabolically important radioactively labelled derivatives of polycyclic aromatic hydrocarbons in a simple and efficient manner, but also requires a rather inexpensive source of tritium.
Anthracene Fluorescence Quenching by a Tetrakis (Ketocarboxamide) Cavitand
2014
Quenching of both fluorescence lifetime and fluorescence intensity of anthracene was investigated in the presence of a newly derived tetrakis (ketocarboxamide) cavitand at various concentrations. Time-correlated single photon counting method was applied for the lifetime measurements. A clear correlation between the fluorescence lifetime of anthracene as a function of cavitand concentration in dimethylformamide solution was observed. The bimolecular collisional quenching constant was derived from the decrease of lifetime. Fluorescence intensity was measured in the emission wavelength region around 400 nm as a result of excitation at 280 nm. Effective quenching was observed in the presence of…
Anti-Pseudomonas aeruginosa activity of hemlock (Conium maculatum, Apiaceae) essential oil
2018
Conium maculatum is a nitrophilous weed belonging to the Apiaceae family and occurring in hedgerows, pastures, waste ground, along rivers and roadsides. Little is known on the chemistry and bioactivity of other secondary metabolites occurring in the plant. In the present work, we have analysed the chemical composition and antimicrobial activity of the essential oils hydrodistilled from leaves and inflorescenes of C. maculatum growing in Sicily, Italy. The composition of essential oils was achieved by gas chromatography-mass spectrometry (GC-MS) analysis, whereas the inhibitory effects on the growth of two Gram negative strains, namely Escherichia coli and Pseudomonas aeruginosa were assesse…
Chemical composition of the essential oil from Thapsia garganica L. (Apiaceae) grown wild in Sicily and its antimicrobial activity.
2015
In this study, the chemical composition of the essential oil from flowers and leaves of Thapsia garganica L. collected in Sicily was evaluated by GC and GC-MS. The main components of T. garganica flower oil (T.f.) were chamazulene (58.3%), humulene oxide II (9.0%), tricosane (8.2%) and pentacosane (8.2%). Also the oil from leaves (T.l.) was characterised by high content of chamazulene (49.2%). Other abundant metabolites were 1,4-dimethylazulene (18.5%), (E)-phytol (6.3%) and neophytadiene (5.1%). The comparison with other studied oils of genus Thapsia is discussed. Antimicrobial activity against several micro-organisms, including some ones infesting historical art craft, was also determined.
Biomedical Applications of Polylactide (PLA) and Its Copolymers.
2018
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The Nonvolatile and Volatile Metabolites of Prangos ferulacea and Their Biological Properties
2019
Abstract Prangos ferulacea (L.) Lindl. (Fam. Apiaceae), an orophilous species of eastern Mediterranean and western Asia, possesses a number of biological properties that are worthy of exploitation in different fields. Phytochemical investigations revealed the presence of coumarins, prenyl-coumarins, and furano-coumarins as the main constituents of this species, as well as several flavonoids. Among prenyl-coumarins, osthol is a promising apoptotic agent quite selective toward cancer cells. In addition, the essential oils have been extensively investigated, and several chemotypes have been identified. This work reviews the literature on this species published between 1965 and 2018, describes …
Anti-arthritic activity of a lipophilic woad (Isatis tinctoria) extract
2006
A dichloromethane extract of Isatis tinctoria was tested in the adjuvant-induced arthritis model in rats. The extract (150 mg/kg p. o.) leads to a significant reduction of paw oedema. Radiographic, histological and clinical assessment confirmed reduced damage of cartilage and signs of inflammatory response in comparison to untreated control. No significant differences were observed in the tissular levels of cyclooxygenases 1 and -2, and of inducible nitric oxide synthase in Isatis treated and untreated animals. High dose treatment with Isatis extract for two weeks did not result in macroscopic lesions of the gastric mucosa.
Chemical Constituents and Pharmacological Properties ofPoria cocos
2011
Poria cocos (Polyporaceae) is a saprophytic fungus that grows in diverse species of Pinus. Its sclerotium, called fu-ling or hoelen, is used in traditional Chinese and Japanese medicine for its diuretic, sedative, and tonic effects. Various studies of this fungus have demonstrated its marked anti-inflammatory activity in different experimental models of acute and chronic inflammation. It is widely used as a constituent of many preparations in Asian medicine, but the number of research papers on its clinical properties is insufficient for establishing its efficacy and safety from a scientific point of view. In this review, we have compiled all the published data concerning the chemistry, pha…
Pharmacological Properties of Shikonin – A Review of Literature since 2002
2013
The naphthoquinone shikonin is the main active principle of Zicao, a traditional Chinese herbal medicine made from the dried root of Lithospermum erythrorhizon. Studies carried out over the past 30 years have provided a scientific basis for the use of Zicao which has been long employed in folk medicine to treat a variety of inflammatory and infectious diseases. In particular, shikonin has been shown to possess many diverse properties, including antioxidant, anti-inflammatory, antithrombotic, antimicrobial, and wound healing effects. The fact that shikonin shows so many beneficial properties has increased the interest in this molecule dramatically, especially in the past few years. The aim o…
Polycerasoidol, a Natural Prenylated Benzopyran with a Dual PPARα/PPARγ Agonist Activity and Anti-inflammatory Effect
2019
Dual peroxisome proliferator-activated receptor-α/γ (PPARα/γ) agonists regulate both lipid and glucose homeostasis under different metabolic conditions and can exert anti-inflammatory activity. We investigated the potential dual PPARα/γ agonism of prenylated benzopyrans polycerasoidol (1) and polycerasoidin (2) and their derivatives for novel drug development. Nine semisynthetic derivatives were prepared from the natural polycerasoidol (1) and polycerasoidin (2), which were evaluated for PPARα, -γ, -δ and retinoid X receptor-α activity in transactivation assays. Polycerasoidol (1) exhibited potent dual PPARα/γ agonism and low cytotoxicity. Structure–activity relationship studies revealed th…