New Nitric Oxide Inhibitory Spirostane Glycosides from Polygonatum kingianum Collett & Hemsl

Two new spirostane glycosides, (25 R)-12 β-hydroxyspirost-5-en-3 β-yl O- β-D-glucopyranosyl-(1→4)- β-D-galactopyranoside (1) and (25 S)-spirost-5-en-7-one-3 β-yl O- β-D-glucopyranosyl-(1→2)- β-D-glucopyranosyl-(1→4)- β-D-galactopyranoside (2), and a known spirostane glycoside, funkioside C (3), were isolated from the roots of Polygonatum kingianum Collett & Hemsl. (Asparagaceae). Their structures were determined by extensive analysis of mass spectrometry high resolution electron spray ionization mass spectrum and nuclear magnetic resonance spectral data, as well as by comparison of the spectral data with those reported in the literature. Compound 2 showed inhibitory effects on nitric oxide production in the lipopolysaccharide stimulated RAW 264.7 cells with an IC50 value of 8.78 ± 0.05 µM compared to a value of 7.12 ± 0.08 µM for the positive control compound, NG-monomethyl-L-arginine.

A New Thiazinedione Glycoside From the Fruits of Xanthium strumarium L.

A total of 4 thiazinedione derivatives including 1 new thiazinedione glycoside (1) and 3 known compounds (2-4) were isolated from the fruits of Xanthium strumarium L. Their chemical structures were determined as 7-hydroxymethyl-8,8-dimethyl-4,8-dihydrobenzo[1,4]-thiazine-3,5-dione-11- O-[ β-D-glucopyranosyl-(1→6)- O-β-D-glucopyranoside] (1), 7-hydroxymethyl-8,8-dimethyl-4,8-dihydrobenzo[1,4]-thiazine-3,5-dione-11- O-[ β-D-apiofuranosyl-(1→6)- O- β-D-glucopyranoside] (2), xanthiside (3), and xanthiazone (4) by extensive nuclear magnetic resonance spectroscopic and high-resolution electron spray ionization mass spectrum analysis and by comparison of the spectral data with those reported in the literature. Compounds 3 and 4 exhibited cytotoxic activity against lung carcinoma (SK-LU-1), human breast carcinoma (MCF-7), hepatocellular carcinoma (HepG2), and skin melanoma (SK-Mel-2) cell lines with half-maximal inhibitory concentration (IC50) values ranging from 27.0 ± 1.1 to 43.2 ± 1.8 µM.

A New Phenylethanoid Glycoside From the Leaves of Rosmarinus officinalis With Nitric Oxide Inhibitory Activity

A new phenylethanoid glycoside, named rosmacinalis (1), and 6x known compounds {2-phenylethyl O-α-L-rhamnopyranosyl-(1‴→6″)- O-β-D-glucopyranoside (2), clinopodiolide C (3), rosmanol (4), 7 α-methoxyrosmanol (5) 7 β-methoxyrosmanol (6) and carnosol (7)} were isolated from the leaves of Rosmarinus officinalis. Their structures were determined by extensive analysis of high-resolution electron spray ionization mass spectrum and nuclear magnetic resonance spectral data, as well as by comparison of the spectral data with those reported in the literature. Anti-inflammatory activity of compounds 1‐7 was evaluated by their inhibition of NO production in lipopolysaccharide-stimulated RAW 264.7 cells. At a concentration of 100 µM, compounds 1 and 2 exhibited inhibitory rates of 47.1% ± 2.2% and 44.5% ± 1.3%, respectively, while compounds 3‐7 showed a cytotoxic effect. After dilution to a concentration of 20 µM, except compound 7, compounds 1‐6 did not show a cytotoxic effect. Their NO inhibitory rates ranged from 14.2% ± 1.3% to 31.1% ± 1.9%.

Thermal ionization of tetramethyltetrazene molecules on NaAuy surface

Adsorption of tetramethyltetrazene on NaAuy surface leads to formation of aromatic compounds constituting thermal ionization mass spectrum, in accordance with the ionization rules of nitrogen-containing molecules established earlier. The suggested mechanism of tetramethyltetrazene adsorption on NaAuy surface is characteristic of azide adsorption on metal surfaces.

Structure, anion, and solvent effects on cation response in ESI-MS

<p>The abundance of an ion in an electrospray ionization mass spectrum is dependent on many factors beyond just solution concentration. Even in cases where the ions are permanently charged and do not rely on protonation or other chemical processes to acquire the necessary charge, factors such as cation structure, molecular weight, solvent, and the identity of the anion can perturb results. Screening of a variety of combinations of cation, anion and solvent provided insight into some of the more important factors. Rigid cations and high conductivity anions tended to provide the highest responses, while acetonitrile was the most accurate solvent for reflecting solution composition. Functional groups that had affinity for the solvent tended to depress response. These observations will provide predictive power when accounting for ions that for reasons of high reactivity can not be isolated.</p><br>

Structure, anion, and solvent effects on cation response in ESI-MS

<p>The abundance of an ion in an electrospray ionization mass spectrum is dependent on many factors beyond just solution concentration. Even in cases where the ions are permanently charged and do not rely on protonation or other chemical processes to acquire the necessary charge, factors such as cation structure, molecular weight, solvent, and the identity of the anion can perturb results. Screening of a variety of combinations of cation, anion and solvent provided insight into some of the more important factors. Rigid cations and high conductivity anions tended to provide the highest responses, while acetonitrile was the most accurate solvent for reflecting solution composition. Functional groups that had affinity for the solvent tended to depress response. These observations will provide predictive power when accounting for ions that for reasons of high reactivity can not be isolated.</p><br>