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- Antihypertensive effect of spent brewer yeast peptidePublication . Amorim, M.; Marques, C.; Pereira, J. O.; GuardĂŁo, L.; Martins, M. J.; OsĂłrio, H.; Moura, D.; Calhau, C.; Pinheiro, H.; Pintado, M.Numerous studies have investigated dietary approaches to prevent chronic lifestyle-related diseases, including hypertension. Spent brewer's yeast is the second largest byproduct originated by the brewing industry and it deserves considerable attention because of its high nutritional value, ca. 40% of its dry mass is rich in protein which can be hydrolyzed into biologically active peptides. To upgrade this byproduct, the aim of this study was initially in vitro assessment of biological properties, e.g. ACE inhibition and antioxidant activity, and then, the in vivo effect in short-term oral antihypertensive effect of hydrolyzed yeast fractions on a well characterized model to study hypertension - Spontaneously Hypertensive Rats (SHR). Here, it was demonstrated that the fraction with molecular weight below 3 kDa containing tri and tetra- peptides with hydrophobic amino acid residues - SPQW, PWW and RYW, causes the most noticeable decrease in systolic, diastolic and mean blood pressure of SHR and shows highest antioxidant effect. These properties highlight the potential use of yeast extract as nutraceutical or functional food ingredient for the management and treatment of hypertension with antioxidant effect.
- Optical fiber bioanalyzer based on enzymatic coating matrix for catecholamines and their metabolites assessment in patients with down syndromePublication . Silva, Lurdes I. B.; Gomes, A. M.; Pintado, M. M.; Pinheiro, H.; Moura, D.; Freitas, Ana C.; Rocha-Santos, Teresa A. P.; Pereira, M. E.; Duarte, A. C.The urinary levels of catecholamines [adrenaline (AD), noradrenaline (NA), and dopamine (DA)] and their metabolites [L-3,4-dihydroxyphenylalanine (L-DOPA), and 3,4-dihydroxyphenylacetic acid (DOPAC)], as indicators of physiological stress, were assessed in 40 patients with Down syndrome (DS). The analysis was performed by an optical fiber (OF) bioanalyzer; which was constituted by two main components: a miniaturized chromatographic system and a detection system based on an OF coated with an enzymatic matrix. In this study some working conditions such as, number of fibers in the miniaturized chromatographic column, number of dips for sensitive coating deposition, temperature and time of cure of the sensitive matrix, were optimized in order to achieve higher analytical performance. After tested for calibration the bioanalyzer was applied to urine samples analysis of catecholamines and their metabolites, comparing the results with those obtained by both, a classical analytical method, namely high performance liquid chromatography coupled to an electrochemical detector (HPLC-ED), and an OF biosensor based on a sensitive cladding of laccase (LacOF biosensor). The results of catecholamines in patients with DS revealed that 15% and 22.5% of the analyzed subjects showed DA and AD concentrations, respectively, above the pathological levels. In the determinations of NA, the 40 samples showed concentration values below the normal levels, while in the determination of catecholamines metabolites 5% of the urine samples showed values above 118 and 1681 for L-DOPA and DOPAC, respectively. Index TermsâCatecholamines analysis, down syndrome, HPLC-ED, OF bioanalyzer.