Manuela Amorim

Novel whey-derived peptides with inhibitory effect against angiotensin-converting enzyme: in vitro effect and stability to gastrointestinal enzymes.

Whey protein concentrate (WPC) was subjected to enzymatic hydrolysis by proteases from the flowers of Cynara cardunculus, and the resulting angiotensin-converting enzyme (ACE)-inhibitory effect was monitored. The whole WPC hydrolysate exhibited an IC(50) value of 52.9 ± 2.9 μg/mL, whereas the associated peptide fraction with molecular weight below 3 kDa scored 23.6 ± 1.1 μg/mL. The latter fraction was submitted to RP-HPLC, and 6 fractions were resolved that exhibited ACE-inhibitory effects. Among the various peptides found, a total of 14 were identified via sequencing with an ion-trap mass spectrometer. Eleven of these peptides were synthesized de novo--to validate their ACE-inhibitory effect, and also to ascertain their stability when exposed to simulated gastrointestinal digestion. Among them, three novel, highly potent peptides were found, corresponding to α-lactalbumin f(16-26)--with the sequence KGYGGVSLPEW, α-lactalbumin f(97-104) with DKVGINYW, and β-lactoglobulin f(33-42) with DAQSAPLRVY; their IC(50) values were as low as 0.80 ± 0.1, 25.2 ± 1.0 and 13.0 ± 1.0 μg/mL, respectively. None of them remained stable in the presence of gastrointestinal enzymes: they were partially, or even totally hydrolyzed to smaller peptides--yet the observed ACE-inhibitory effects were not severely affected for two of those peptides.

Nanoencapsulation of bovine lactoferrin for food and biopharmaceutical applications

Lactoferrin has for long captured the interest of many researchers as a natural compound with a wide variety of uses. Lactoferrin is a monomeric, iron-binding 80 kDa glycoprotein, and appears to be the subfraction of whey with the best documented antiviral, antimicrobial, anticancer and immune modulating/enhancing effects. It belongs to the family of transferrin proteins, and serves to control iron levels in body fluids by sequestering and solubilizing ferric iron. In the present research effort, production of lactoferrin derivatives (starting from a purified commercial extract), encompassing full stabilization of its three-dimensional structure, has been attempted via nanoencapsulation within lipid nanovesicles, integrating a multiple water-in-oil-in-water emulsion. Long-term storage of the multiple nanoemulsions produced did not lead to leaching of protein, thus proving the effectiveness of the encapsulation procedure. Furthermore, lactoferrin nanovesicle derivatives prepared under optimal conditions were successfully employed at lab-scale antimicrobial trials.

Impact of enzyme- and ultrasound-assisted extraction methods on biological properties of red, brown, and green seaweeds from the central west coast of Portugal.

Seaweeds are an excellent source of bioactive compounds, and therefore the use of sustainable and food compatible extraction methods such as enzyme-assisted (EAE) and ultrasound-assisted extraction were applied on Sargassum muticum, Osmundea pinnatifida, and Codium tomentosum. Extracts were evaluated for proximate characterization and biological properties. Higher extraction yields were observed for C. tomentosum EAE (48-62%; p < 0.05 for Cellulase and Viscozyme), followed by O. pinnatifida (49-55%; p < 0.05 except Alcalase) and S. muticum (26-31%; p < 0.05). S. muticum extracts presented the highest nitrogen (25 ± 2 mg/glyoph extract) and total phenolics (261 ± 37 μgcatechol equiv/glyoph extract) contents, whereas higher sugars (78 ± 14 mgglucose equiv/glyoph extract) including sulfated polysaccharide (44 ± 8 mgNa2SO4 acid/glyoph extract) contents characterized O. pinnatifida extracts. A higher effect on hydroxyl-radical scavenging activity (35-50%) was observed for all extracts, whereas S. muticum Alcalase and C. tomentosum Cellulase extracts exhibited higher prebiotic activity than fructooligosaccharides. O. pinnatifida and C. tomentosum EAE showed inhibitory potential against α-glucosidase (38-49%).

Natural extracts into chitosan nanocarriers for rosmarinic acid drug delivery

Abstract Context: Nanotechnology can be applied to deliver and protect antioxidants in order to control the oxidative stress phenomena in several chronic pathologies. Chitosan (CS) nanoparticles are biodegradable carriers that may protect antioxidants with potent biological activity such as rosmarinic acid (RA) in Salvia officinalis (sage) and Satureja montana (savory) extracts for safe and innovative therapies. Objective: Development and characterization of CS nanoparticles as a stable and protective vehicle to deliver RA for medical applications using natural extracts as sage and savory. Materials and methods: Antioxidant-CS based nanoparticles were prepared by ionic gelation with sodium tripolyphosphate (TPP), at pH 5.8 with a mass ratio of 7:1 (CS:TPP), with a theoretical antioxidant-CS loading of 40–50%. The nanoparticles were then characterized by different methods such as photon correlation spectroscopy, laser Doppler anemometry, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR), high-performance liquid chromatographic (HPLC), association efficiency, and antioxidant activity. Results and discussion: Individual and small sizing nanoparticles, around 300 nm, were obtained. SEM confirmed smooth and spherical nanoparticles after freeze-drying. No chemical interactions were found between antioxidants and CS, after encapsulation, by DSC and FTIR. The association efficiency was 51.2% for RA (with 40% loading) and 96.1 and 98.2% for sage and savory nanoparticles, respectively (both with 50% loading). Antioxidant activity values were higher than 0.0348 eq [Asc. Ac.] g/L/g extract and 0.4251 µmol/eq Trolox/g extract. Conclusion: The extracts under study are promising vehicles for RA drug delivery in CS nanocarriers.

Chemical and structural characterization of Pholiota nameko extracts with biological properties

Edible mushrooms including Pholiota nameko are excellent sources of extractable bioactive compounds with much to explore. Enzymatic extractions with Cellulase and Viscozyme were responsible for highest extraction yields (67-77%). No strong antioxidant activity was observed although extracts were able to scavenge ABTS(+) and OH(+). Potential prebiotic activity was observed in all extracts, some increasing 1.4-2 Log cycles of Lactobacillus acidophilus La-5 and Bifidobacterium animalis BB12. 30-50% α-glucosidase inhibition was observed in ultrasound, Flavourzyme and Cellulase extracts. Flavourzyme and Cellulase extracts are richer in macro (Mg, K and P) and micro elements (Zn, Mn and Fe) in comparison to mushroom. Monosaccharides content and profile varied slightly among both extracts with predominance of glucose, galactose and mannose with no uronic acids detection; Flavourzyme extract reported higher free amino acids content. Presence of α and β-glycosidic structures such as glucans and glucan-protein complexes are among the polysaccharides found in both extracts.

Use of coffee by-products for the cultivation of Pleurotus citrinopileatus and Pleurotus salmoneo-stramineus and its impact on biological properties of extracts thereof

1 CBQF Centro de Biotecnologia e Qu ımica Fina – Laborat orio Associado, Escola Superior de Biotecnologia, Universidade Cat olica Portuguesa, Rua Arquiteto Lob~ao Vital, 172, 4200-374 Porto, Portugal 2 Bioinvitro, Biotecnologia Lda, Rua Eng. Jos e Rodrigo Carvalho, 95, 4480-484, Arvore, Vila do Conde, Portugal 3 REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Polit ecnico do Porto, Rua Dr. Ant onio Bernardino de Almeida, 431, 4200-072 Porto, Portugal