Browsing by Author "Lopez Alarcon, Camilo"

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    Effect of isoespintanol isolated from Oxandra cf. xylopioides against DNA damage of human lymphocytes
    (UNIV KARACHI, 2018) Elena Marquez Fernandez, Maria; Carolina Munoz Lassos, Diana; Bautista Lopez, Juan; Zapata, Karol; Puertas Mejia, Miguel Angel; Lopez Alarcon, Camilo; Alberto Rojano, Benjamin
    Synthetic antioxidants are used in the food and pharmaceutical industry, however, there is concern about their safety; this has prompted the search for new antioxidants that are effective, safe and act at low concentrations. The objective of this study is to evaluate the oxygen radical scavenging capacity and clastogenic effect of the Isoespintanol /2-isopropyl-3,6-dimethyl-5-methylphenol) in DNA of human lymphocyte compared with the BHA (Butylated hydroxyanisole). The oxygen radical scavenging ability was evaluated by methods ORAC(FL) and ORAC(PGR), genotoxicity was determined by comet assay and data analysis was performed using ANOVA and Duncan test. The results show that the oxygen radical scavenging capacity of the BHA is higher than Isoespintanol, however according to the reactivity concept proposed by Lopez-Alarcon and Lissi, the Isoespintanol it is more reactive than BHA. Furthermore, according to some studies, BHA presented adverse effects on the health of consumers. Comet assay results revealed that at concentrations between 3 and 1620 mu M the Isoespintanol don't show clastogenic effects on DNA. In conclusion, the antioxidant capacity for the BHA is higher than Isoespintanol, but considering reactivity concepts proposed by Lopez-Alarcon and Lissi, the Isoespintanol is faster to neutralize radicals that the BHA, furthermore, according to the National Institute of Health "BHA" is a human carcinogen.
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    Nitroaryl-1,4-dihydropyridines as antioxidants against rat liver microsomes oxidation induced by iron/ascorbate, Nitrofurantoin and naphthalene
    (PERGAMON-ELSEVIER SCIENCE LTD, 2007) Letelier, Maria Eugenia; Entrala, Paz; Lopez Alarcon, Camilo; Gonzalez Lira, Victor; Molina Berrios, Alfredo; Cortes Troncoso, Juan; Jara Sandoval, Jose; Santander, Paola; Nunez Vergara, Luis
    1,4-Dihydropyridines (DHPs) used in the treatment of cardiovascular diseases, are calcium channel antagonists and also antioxidant agents. These drugs are metabolized through cytochrome P-450 oxidative system, majority localized in the hepatic endoplasmic reticulum. Several lipophilic drugs generate oxidative stress to be metabolized by this cellular system. Thus, DHP antioxidant properties may prevent the oxidative stress associated with hepatic biotransformation of drugs.
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    Time-dependence of Ferric Reducing Antioxidant Power (FRAP) index in Chilean apples and berries
    (ARCHIVOS LATINOAMERICANOS NUTRICION, 2011) Henriquez, Carolina; Lopez Alarcon, Camilo; Gomez, Maritza; Lutz, Mariane; Speisky, Hernan
    We hypothesize that the Ferric Reducing Antioxidant Power (FRAP) assay that follows the reaction of Fe3+-TPTZ at 593 nm underestimates the antioxidant capacity of fruits, since the standardized time of the reaction (4 min) is not enough to titrate all the reducing compounds available. We measured FRAP, total phenolics and anthocyanins content in a variety of Chilean berry fruits (blueberries, blackberries, raspberries and strawberries) and apples (cv. Fuji, Granny Smith, Pink Lady, Red Delicious and Royal Gala). Taking into account the dependence of FRAP on the time course of the reaction, we propose to measure FRAP indexes after 1 min (FRAP-1), 30 min (FRAP-30) and 120 min (FRAP-120) of incubation. Most fruit extracts showed significant correlations between the antioxidant capacity and the incubation time, although in some cases the FRAP indexes did not correlate with the total phenolics and/or anthocyanins content. In fact, in apples and berries the correlation between anthocyanins content and FRAP indexes decreased with the incubation time. It is concluded that the fruit extracts analyzed require an incubation period higher than the established in the original experimental protocol to reach the equilibrium, due to the presence of a complex mixture of antioxidant compounds. In addition, a kinetic profile should be realized in each sample studied to establish the most suitable incubation period to titrate all the reactive antioxidant species.