Evaluation of the in vitro anti-hyperglycemic effect of Cinnamomum cassia derived phenolic phytochemicals, via carbohydrate hydrolyzing enzyme inhibition.

Cinnamomum cassia (cinnamon) proanthocyanidins (PACs) are believed to have anti-hyperglycemic potential via stimulation of insulin sensitivity. The present study investigates the carbohydrate hydrolyzing enzyme inhibition of cinnamon PACs. Five grams of cinnamon bark powder were extracted in 100 mL acetone solution (CAE) (acetone: water: hydrochloric acid, 70:29.9:0.01) for 2 h at room temperature and in 100 mL deionized water for 30 min at 90 °C (CWE). PACs were purified from CAE using LH-20 (CAE-PAC) to be further evaluated. PAC contents were evaluated by 4-Dimethylaminocinnamaldehyde (DMAC) assay and yielded 795, 177 and 123 mg/g, for CAE-PAC, CAE and CWE respectively. The total phenolic contents of CAE and CWE were determined to be 152 and 134 mg/g respectively. All extracts were adjusted to the same PAC content (180, 90, 45 and 20 µg) and the inhibitory activity against rat α-glucosidase was determined. The CAE-PAC fraction had very low rat α-glucosidase inhibitory activity, CAE had the highest (IC50 0.474 mg/mL total phenolic (TP) basis) followed by CWE (IC50 0.697 mg/mL TP basis). The specific maltase and sucrase inhibitory activities were determined and CAE (IC50 0.38 and 0.10 mg/mL TP basis) had higher inhibition than CWE (IC50 0.74 and 0.37 mg/mL TP basis). Results suggest that the observed bioactivity is not PAC dependent and that CAE has a higher anti-hyperglycemic potential than CWE via inhibition of carbohydrate hydrolyzing enzymes.

CD8+ lymphocyte depletion without SIV infection does not produce metabolic changes or pathological abnormalities in the rhesus macaque brain.

BACKGROUND: Simian immunodeficiency virus (SIV) infection and persistent CD8(+) lymphocyte depletion rapidly leads to encephalitis and neuronal injury. The objective of this study is to confirm that CD8 depletion alone does not induce brain lesions in the absence of SIV infection. METHODS: Four rhesus macaques were monitored by proton magnetic resonance spectroscopy ((1) H-MRS) before and biweekly after anti-CD8 antibody treatment for 8 weeks and compared with four SIV-infected animals. Post-mortem immunohistochemistry was performed on these eight animals and compared with six uninfected, non-CD8-depleted controls. RESULTS: CD8-depleted animals showed stable metabolite levels and revealed no neuronal injury, astrogliosis or microglial activation in contrast to SIV-infected animals. CONCLUSIONS: Alterations observed in MRS and lesions in this accelerated model of neuroAIDS result from unrestricted viral expansion in the setting of immunodeficiency rather than from CD8(+) lymphocyte depletion alone.

Characterization of surface and photooxidative properties of supported metal oxide photocatalysts using solid-state NMR.

In situ solid-state NMR (SSNMR) methodologies have been used to investigate the surface properties and photooxidative reactivities of a number of metal oxide photocatalysts. Adsorption of ethanol on single monolayers of TiO2, SnO2, V205, and WO3 supported on porous Vycor glass results in the formation of hydrogen-bonded ethanol species and metal-bound ethoxide species. The chemical shift of the metal-bound ethoxide species varies with the metal oxide catalyst while the chemical shift of the hydrogen-bonded species is independent of the metal oxide. X-ray powder diffraction, UV-VIS spectroscopy, and SSNMR investigations of ethanol adsorption show that increasing the number of monolayers of TiO2 on the Vycor surface changes the morphology of the catalyst from amorphous at a single monolayer coverage to anatase at a four monolayer coverage. The rate of photocatalytic oxidation of ethanol, acetone, and 2-propanol also increases with increasing TiO2 monolayer coverage.