This study aimed to discover and prepare novel angiotensin converting enzyme (ACE) inhibitory peptides from almond protein and further evaluate the effect on endothelial function of human umbilical vascular endothelial cells (HUVECs). Almond protein was hydrolyzed using a two-stage alcalase-protamex hydrolysis process, and the hydrolysates were subjected to a series of separations, ultrafiltration, gel filtration chromatography, and reversed-phased preparative chromatography, to obtain the active peptides. Seven ACE inhibitory fractions with the molecular weight below 1.5 kDa were isolated and prepared, and two purified ACE inhibitory peptides with the IC50 values of 67.52 ± 0.05 and 43.18 ± 0.07 μg mL(-1), were identified as Met-His-Thr-Asp-Asp and Gln-His-Thr-Asp-Asp, respectively. Then the effect of two ACE inhibitory peptides on the endothelial function of HUVECs was evaluated. Results showed that the two potent ACE inhibitory peptides significantly regulated the release of nitric oxide and endothelin in HUVECs. These results suggest that almond peptides have potential as an antihypertensive nutraceuticals or a functional food ingredient.
Microwave-assisted extraction was optimized with response surface methodology for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii. The optimized extraction procedure was achieved by soaking the sample with 70% methanol (1:15, v/v) for 30 min, and then microwave irradiation for 11 min at a power of 600 W. Coupling the extraction process with HPLC-fluorescence presented good recovery, satisfactory precision, and good linear relation. Compared with a method from the Chinese Pharmacopoeia, the proposed method enables higher extraction efficiency and more aecurate analytical results. It can be of Potential value in quality assessment of Radix Puerariae thomsonii medicinal materials.
A flow injection catalytic method is proposed for determination of trace vanadium based on its catalytic action on a new indicator reaction between Victoria blue B (VBB) and potassium bromate in the presence of citric acid as an activator and in dilute sulfuric acid medium. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of VBB injected at the maximum absorption wavelength of 618 nm. The detection limit is 0.5 ng ml' 1 and is independent of the initial valence state of vanadium. The relative standard deviation is 1.5% obtained from 11 standard solutions each containing 2115
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.