Browsing by Author "Shahidi, Fereidoon "

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    Do Flavonoids from Durum Wheat Contribute to Its Bioactive Properties? A Prospective Study
    (2021) de Camargo, Adriano Costa; de Souza Silva, Anna Paula; Soares, Jackeline Cintra; de Alencar, Severino Matias; Handa, Cintia Ladeira; Cordeiro, Karina Silva; Figueira, Marcela Souza; Sampaio, Geni R.; Torres, Elizabeth A. F. S.; Shahidi, Fereidoon; Schwember, Andres R.
    A clear gap with respect to the potential biological properties of wheat flavonoids exists in the available literature. This information is crucial for breeding programs aiming to produce new varieties presenting improved health benefits. Accordingly, advanced breeding lines of whole durum wheat were evaluated in this contribution. The highest recovery of phenolics was achieved using aqueous acetone (50:50, v/v), as verified by multi-response optimization, thus showing that phenolics could be largely underestimated by employing an inappropriate extraction. The concentration of derivatives of apigenin, the main phenolics present, ranged from 63.5 to 80.7%, as evaluated by LC-ESI-QTOF-MS. Phenolics from the breeding line 98 exhibited the highest ability in scavenging peroxyl radicals, reducing power as well as in terms of inhibition of pancreatic lipase activity, a key enzyme regulating the absorption of triacylglycerols. In contrast, none of the samples exhibited a significant anti-diabetic potential. Despite their high concentration compared to that of phenolic acids, results of this work do not support a significant antioxidant and pancreatic lipase inhibitory effect of durum wheat flavonoids. Therefore, breeding programs and animal and/or human trials related to the effect of durum wheat flavonoids on oxidative stress and absorption of triacylglycerols are discouraged at this point.
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    Evaluation of the antioxidant capacity of food samples: a chemical examination of the oxygen radical absorbance capacity assay
    (WILEY-BLACKWELL, 2018) Dorta Pérez, Eva; Fuentes Lemus, Eduardo Felipe; Speisky, Hernan; Lissi Gervaso, Eduardo A.; López Alarcón, Camilo Ignacio; Apak, Resat; Capanoglu, Esra; Shahidi, Fereidoon
    This chapter describes, from a critical point of view, the main in vitro methodologies employed to assess the antioxidant capacity (AC) of food samples. Considering the wide use of the oxygen radical absorbance capacity (ORAC) assay, it presents a chemical examination of this methodology. The methods for AC evaluation are based on different strategies; these include the use of colored and stable free radicals, evaluation of the capacity of antioxidants to reduce cupric or ferric ions, estimation of the ability of phenolic compounds (PC) to protect a target molecule exposed to a free radical source, and evaluation of the capacity of PC to form nanoparticles. When the antioxidant activity of a particular sample is evaluated, it is recommended to know the meanings and limitations of the assays being employed. In the case of the ORAC assay, the nature of the free radicals generated during the thermolysis of AAPH should also be considered.
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    Honeybee Pollen From Southern Chile: Phenolic Profile, Antioxidant Capacity, Bioaccessibility, and Inhibition of DNA Damage
    (2022) Bridi, Raquel; Echeverria, Javier; Larena, Arturo; Nunez Pizarro, Paula; Atala, Elias; De Camargo, Adriano Costa; Oh, Won Young; Shahidi, Fereidoon; Garcia, Olga; Ah-Hen, Kong S.; Montenegro, Gloria
    Honeybee pollen (HBP) chemical composition is highly variable conforming to the floral and geographical origin of the pollen grains. The beneficial effects and functional properties of the HBP are well-known and have been mainly attributed to their high content of antioxidant polyphenols. In this work, twelve HBPs samples from the Southern region of Chile (X Region de Los Lagos) were characterized for the first time according to their botanical origin, phenolic composition, and antioxidant activity. The in vitro gastrointestinal digestion assay was done to simulate the human upper digestive tract. Selected honeybee pollen extracts (HBPEs) were assessed as bioaccessible fractions during an in vitro gastrointestinal digestion. Contents of phenolic compounds, antioxidant capacity, and recovery index of quercetin, myricetin, and cinnamic acid were monitored in different steps of gastrointestinal digestion. Furthermore, the protective effect of in vitro digested HBP towards DNA damage induced by peroxyl radicals was evaluated. The introduced species Brassica rapa L. (Brassicaceae), Lotus pedunculatus Cav. (Fabaceae), and Ulex europaeus L. (Fabaceae) predominated in all the HBPs analyzed, while the native species Buddleja globosa Hope (Scrophulariaceae), Luma apiculata (DC.) Burret (Myrtaceae), Embothrium coccineum J.R. Forst. & G. Forst. (Proteaceae) and Eucryphia cordifolia Cav. (Cunoniaceae) appeared less frequently. The content of polyphenols and antioxidant capacity in HBPEs achieved full bioaccessibility at the end of the intestinal digestion step. However, results obtained by a state-of-the-art technique (i.e. HPLC-DAD) demonstrated relatively low values of bioaccessible quercetin and cinnamic acid after the digestion process. In contrast, myricetin showed a high bioaccessibility in the intestinal digestion steps. The protective effect of in vitro digested HBP towards DNA damage induced by peroxyl radicals showed promising results (up to 91.2% protection). In conclusion, HBPs from the X Region de Los Lagos are rich sources of phenolic antioxidants that protect DNA from strand breakage. Therefore, the potential of HBPEs in preventing gastric and/or intestinal cancer should be further considered.
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    New Findings in the Amino Acid Profile and Gene Expression in Contrasting Durum Wheat Gluten Strength Genotypes during Grain Filling
    (AMER CHEMICAL SOC, 2020) Araya Flores, Jorge Andrés; Guzman, Carlos; Matus, Iván; Parada Salazar, Roberto Andrés; Jarpa Tauler, Gabriela Teresa; Costa de Camargo, Adriano; Shahidi, Fereidoon; Schwember, Andres R.
    Grain protein composition is important in wheat quality and may influence the amino acidic sequence of bioactive peptides obtained from this feedstock. However, the genetic basis modulating the amino acid profile in durum wheat is not well-understood. Therefore, strong and weak gluten strength durum wheat genotypes were evaluated for their amino acid composition along grain filling. Strong gluten strength lines showed higher expression levels of low-molecular-weight glutenin-related genes between 21 and 35 days post-anthesis (DPA) and exhibited up to 43.5% more alanine than the weak lines at 42 DPA, which was supported by the higher expression levels of putative alanine amino transferase genes in strong genotypes. Therefore, with the involvement of chemistry and molecular biology, the results present here may influence the science of wheat.
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    Should we ban total phenolics and antioxidant screening methods? The link between antioxidant potential and activation of NF-κB using phenolic compounds from grape by-products
    (2019) de Camargo, Adriano Costa; Telles Biasoto, Aline Camarao; Schwember, Andres R.; Granato, Daniel; Rasera, Gabriela Boscariol; Franchin, Marcelo; Rosalen, Pedro L.; Alencar, Severino Matias; Shahidi, Fereidoon
    Free radical imbalance is associated with several chronic diseases. However, recent controversies have put in check the validity of colorimetric methods to screen the functionality of polyphenols. Therefore, in this study two antioxidant methods, based on chemical reactions, were tested for their ability in anticipating the reduction of the activation of NF-kappa 3 using LPS-activated RAW 264.7 macrophages, selected as a biological model. Grape processing by-products from winemaking showed higher total phenolic content (TPC), antioxidant capacity towards peroxyl radical (31.1%) as well as reducing power (39.5%) than those of grape juice by-products. The same trend was observed when these samples were tested against LPS-activated RAW 264.7 macrophages by reducing the activation NF-kappa B. Feedstocks containing higher TPC and corresponding ORAC and FRAP results translated to higher reduction in the activation of NF-kappa 3 (36.5%). Therefore, this contribution demonstrates that colorimetric methods are still important screening tools owing their simplicity and widespread application.
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    Soluble Free, Esterified and Insoluble-Bound Phenolic Antioxidants from Chickpeas Prevent Cytotoxicity in Human Hepatoma HuH-7 Cells Induced by Peroxyl Radicals
    (2022) Costa de Camargo, Adriano; Alvarez, Alina Concepción ; Arias-Santé, María Fernanda; Oyarzún, Juan Esteban; Andia, Marcelo E.; Uribe, Sergio; Nunez-Pizarro, Paula; Bustos, Simón M.; Schwember, Andrés R. ; Shahidi, Fereidoon ; Bridi, Raquel