Browsing by Author "Carrasco, Jonathan"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    A high throughput method for detection of cyclooxygenase-2 enzyme inhibitors by effect-directed analysis applying high performance thin layer chromatography-bioassay-mass spectrometry
    (Elsevier, 2023) Oyarzún, Paulina; Carrasco, Jonathan; Peterssen, Darlene; Tereucan, Gonzalo; Aranda, Mario; Henriquez-Aedo, Karem
    A high throughput method was developed to detect bioactive molecules with inhibitory activity over cyclo-oxygenase (COX-2) enzyme applying effect-directed analysis and planar chromatography hyphenated with bioassay and mass spectrometry. The assay was based on the indirect measurement of arachidonic acid trans-formation into prostaglandin with the colorimetric co-substrate N,N,N',N'-tetramethyl-p-phenylenediamine. Inhibitory zones were observed as colorless bands over a blue background. Using a central composite design the critical factors like substrate concentration, enzyme: substrate ratio, reaction time, and co-substrate concentra-tion were optimized. Optimal conditions were achieved with 0.03 mg/mL of arachidonic acid, 0.15 U/mL of COX-2, and 8.21 mg/mL of chromogenic reagent. Method usefulness was challenged analyzing fresh Chiloe's giant garlic (Allium ampeloprasum L) ethanol: water (8:2 v/v) extract, finding COX-2 inhibitors that were pre-liminarily identified as the isomers gamma-glutamyl-S-allyl-L-cysteine and gamma-glutamyl-S-(trans-1-propenyl)-L-cysteine.
  • No Thumbnail Available
    Item
    Multivariate optimization of microwave-assisted enzyme digestion of α-casein for generation of bioactive peptides
    (2023) Lopez, Katherine; Espinoza-Bello, Alejandra; Carrasco, Jonathan; Pena-Farfal, Carlos; Aranda, Mario; Henriquez-Aedo, Karem
    Caseins are the principal milk proteins and serve as an important source of bioactive peptides with diverse beneficial effects for human health, such as antihypertensive, immunomodulating, anti-inflammatory, and antithrombotic. The objective of this study was to optimize, using the design of the experiment, the production of bioactive peptides from alpha-casein applying microwave -assisted enzyme digestion (MAED). The optimal MAED conditions (time, temperature, and enzyme/protein ratio) were established for pepsin (digestion time 4 min, temperature 41 degrees C, and E:P ratio 1:40) and trypsin (digestion time 10 min, temperature 37 degrees C and E:P ratio 1:200.) enzymes. Digestion yields and the intensity of different bioactivities, i.e., antimicrobial, antioxidant, and acetylcholinesterase and alpha glucosidase inhibitory activities, evaluated by the HPTLC-bioassay technique were used as response variables. Trypsin-formed alpha-casein peptides showed antimicrobial, antioxidant, and acetylcholinesterase inhibition activities, while pepsin -formed showed antimicrobial, antioxidant, and alpha-glucosidase inhibition activities. These results demonstrate that MAED is a fast and effective technique for bioactive peptide production from casein proteins.
  • Thumbnail Image
    Item
    Preliminary evaluation of biogenic amines content in Chilean young varietal wines by HPLC
    (2012) Pineda, Angela; Carrasco, Jonathan; Peña Farfal, Carlos Gustavo; Henríquez Aedo, Karem; Aranda Bustos, Mario Antonio