Nitric oxide (NO) has been postulated as a regulator of vascular reactivity, and the current study tested the hypothesis that NO-induced decreased sensitivity to vasoconstrictors persists following removal of NO. Endothelium-denuded segments of rat aorta were incubated 2-4 h at 37 degrees C with the NO donor S-nitroso-N-acetylpenicillamine (SNAP). Incubation produced rightward shifts in concent...

Monomeric alkannin and shikonin (A/S) are potent pharmaceutical substances with a wide spectrum of biological activity and comprise the active ingredients for several pharmaceutical preparations. Therefore, the determination of the impurities, degradation products or byproducts in alkannin and shikonin samples is of great importance. Oligomeric alkannin and shikonin are formed during biosynthes...

The current authors have previously demonstrated that diesel exhaust particles (DEP) enhance antigen-related airway inflammation in mice. Furthermore, a recent study has shown that organic chemicals in DEP, rather than their carbonaceous nuclei, are important contributors to the aggravating effects of airway inflammation. However, the components in DEP responsible for the enhancing effects on t...

In this paper, we present our preliminary studies into naphthoquinones as novel reagents for the detection of latent fingermarks on paper. Latent fingermarks deposited on paper substrates were treated with solutions of selected naphthoquinones in ethyl acetate/HFE-7100, with subsequent heating. The selected compounds were 1,4-dihydroxy-2-naphthoic acid, 1,2-naphthoquinone-4-sulfonate, 2-methoxy...

A simple synthetic strategy to C 2-symmetric bis-spiro-pyrano cage compound 7 involving ring-closing metathesis is reported. The hexacyclic dione 10 was prepared from simple and readily available starting materials such as 1,4-naphthoquinone and cyclopentadiene. The synthesis of an unprecedented octacyclic cage compound through intramolecular Diels-Alder (DA) reaction as a key step is described...

A series of 2-amino(chloro)-3-chloro-1,4-naphthoquinone derivatives (1-11) were investigated for their aromatase inhibitory activities. 1,4-Naphthoquinones 1 and 4 were found to be the most potent compounds affording IC50 values 5.2 times lower than the reference drug, ketoconazole. A quantitative structure-activity relationship (QSAR) model provided good predictive performance (R2CV = 0.9783 a...

Several reports have demonstrated the anticancer activities of plumbagin, a naphthoquinone derivative isolated from plants belonging to Plumbaginaceae family. However, to the best of our knowledge, there are no reports which describe gold nanoconjugation with plumbagin, even though plumbagin is considered to be a promising therapeutic agent. In this report, we demonstrate the fabrication and ch...

AIMS To verify the effects of several 5,8-dimethoxy-1,4-naphthoquinone (DMNQ) derivatives on LPS-induced NO production, cellular ROS levels and cytokine expression in BV-2 microglial cells. MAIN METHODS An MTT assay and FACS flow cytometry were performed to assess the cellular viability and apoptosis and cellular ROS levels, respectively. To examine the expression of pro-inflammatory cytokine...