Browsing by Author "Schmeda-Hirschmann, Guillermo"

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    Free radical scavengers from Cymbopogon citratus (DC.) stapf plants cultivated in bioreactors by the temporary immersion (TIS) principle
    (2007) Tapia, Alejandro; Cheel, Jose; Theoduloz, Cristina; Rodriguez, Jaime; Schmeda-Hirschmann, Guillermo; Gerth, Andre; Wilken, Dirk; Jordan, Miguel; Jimenez-Gonzalez, Elio; Gomez-Kosky, Rafael; Quiala Mendoza, Elisa
    The biomass production of Cynibopogon citratus shoots cultivated in bioreactors according to the temporary immersion (TIS) principle was assessed under different growth conditions. The effect of gassing with CO2-enriched air, reduced immersion frequency, vessel size and culture time on total phenolic and flavonoid content and free radical scavenging effect of the methanolic extracts was measured. From the TIS-culture of C citratus, seven compounds were isolated and identified as caffeic acid (1), chlorogenic acid (2), neochlorogenic acid (3), p-hydroxybenzoic acid (4), p-hydroxybenzoic acid 3-O-beta-D-glUcoside (5), glutamic acid (6) and luteolin 6-C-fucopyranoside (7). The occurrence of compounds 1-7 and their variability in C citratus grown under different TIS conditions was determined by HPLC. The free radical scavenging effect of the methanolic extract and compounds was measured by the discoloration of the free radical 1,1diphenyl-2-picrylhydrazyl (DPPH). The main metabolites in 6- and 8-week-old cultures, both in 5 and 10 1 vessels, were chlorogenic acid (2) (100-113 mg%) and neochlorogenic acid (3) (80119 mg%), while in the cultures with CO2-enriched air and reduced immersion frequency the main compound detected in the extracts was glutamic acid (6) (400 and 670 mg% for the green and white biomass and 619 and 630 mg% for the green and white biomass, respectively). The most active compounds, as free radical scavengers, in the DPPH discoloration assay were caffeic acid (1), chlorogenic acid (2), neochlorogenic acid (3) and the flavonoid luteolin 6-C-fucopyranoside (7).
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    Free radical scavenging activity and secondary metabolites from in vitro cultures of Sanicula graveolens
    (2007) Cheel, Jose; Schmeda-Hirschmann, Guillermo; Jordan, Miguel; Theoduloz, Cristina; Rodriguez, Jaime A.; Gerth, Andre; Wilken, Dirk
    An in vitro propagation system was developed to obtain shoot and root cultures from the Andean spice Sanicula graveolens (Apiaceae). Propagation of shoots, roots and plantlets was achieved by the temporary immersion system. The free radical scavenging effect of the methanol/water (7:3 v/v) extracts was determined by the discoloration of the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH). Total phenolic, flavonoid, chlorogenic acid (CA) and quercetin 3-O-glucoside content in the samples was assessed by spectrophotometry and DAD-HPLC analysis, respectively. On a dry weight basis, the crude extracts showed total phenolic values ranging from 3.57 to 6.93%, with highest content for the root culture sample. Total flavonoid content ranged from 1.23 to 2.23% and was lower for the root culture. Chlorogenic acid and neochlorogenic acid were identified by TLC in all samples. Highest free radical scavenging effect was observed for the root culture which also presented the highest CA content. Two of the shoot culture samples, with similar lC(50) values in the DPPH discoloration assay, also presented close quercetin-3-O-glucoside content.
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    Inhibition of advanced glycation end products and protein oxidation by leaf extracts and phenolics from Chilean bean landraces
    (Wiley, 2022) Ávila, Felipe; Cruz, Nadia; Alarcón-Esposito, Jazmín; Márquez, Katherine; Burgos-Edwards, Alberto; Theoduloz, Cristina; Schmeda-Hirschmann, Guillermo; Nina, Nélida; Paillán, Hernán; Fuentealba Patino, Denis Alberto; Vejar-Vivar, Carmina
    Phenolics can decrease the levels of advanced glycation end products (AGEs) from proteins, but their mechanisms in complex mixtures are poorly understood. Leaf extracts and the main phenolics from Chilean bean (Phaseolus vulgaris) landraces were assessed for their capacity to inhibit AGEs and oxidative modifications on bovine serum albumin incubated with glucose. The leaf extracts of six bean landraces decreased AGEs (fluorescent AGEs and carboxymethyl lysine) and oxidative (Kyn, Di-Tyr, protein carbonyls) modifications. Fluorescent AGEs were characterized by time-resolved techniques. The composition of the extracts was determined by HPLC-DAD-Q-TOF-MS/MS, and the main compounds were quantified by HPLC. Correlations between the levels of AGEs or protein carbonyls with the main phenolics suggested synergic effects of caffeoyl malic acid (CMA) and rutin. The synergic effect was evaluated using mixtures of rutin and CMA, showing a strong decrease in fluorescent AGEs and protein carbonylation compared with the pure single compounds, supporting this finding.
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    Inhibition of advanced glycation end products and protein oxidation by leaf extracts and phenolics from Chilean bean landraces
    (Elsevier Ltd, 2022) Ávila, Felipe; Cruz, Nadia; Alarcón-Esposito, Jazmín; Márquez, Katherine; Burgos-Edwards, Alberto; Theoduloz, Cristina; Schmeda-Hirschmann, Guillermo; Nina, Nélida; Paillán, Hernán; Fuentealba Patino, Denis Alberto; Vejar-Vivar, Carmina
    Phenolics can decrease the levels of advanced glycation end products (AGEs) from proteins, but their mechanisms in complex mixtures are poorly understood. Leaf extracts and the main phenolics from Chilean bean (Phaseolus vulgaris) landraces were assessed for their capacity to inhibit AGEs and oxidative modifications on bovine serum albumin incubated with glucose. The leaf extracts of six bean landraces decreased AGEs (fluorescent AGEs and carboxymethyl lysine) and oxidative (Kyn, Di-Tyr, protein carbonyls) modifications. Fluorescent AGEs were characterized by time-resolved techniques. The composition of the extracts was determined by HPLC-DAD-Q-TOF-MS/MS, and the main compounds were quantified by HPLC. Correlations between the levels of AGEs or protein carbonyls with the main phenolics suggested synergic effects of caffeoyl malic acid (CMA) and rutin. The synergic effect was evaluated using mixtures of rutin and CMA, showing a strong decrease in fluorescent AGEs and protein carbonylation compared with the pure single compounds, supporting this finding.
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    Thermal treatment under oxidative conditions increases the antioxidant and antiglycation activity of Chilean Tortola beans ( Phaseolus vulgaris)
    (2025) Cruz, Nadia; Basoalto-Cubillos, Aracely; Marquez, Katherine; Nina, Nelida; Vallejos-Almirall, Alejandro; Armijo, Francisco; Schmeda-Hirschmann, Guillermo; Avila, Felipe
    The influence of oxygen on the thermal treatment (TT) of secondary metabolite-enriched extracts (SMEEs) from T & oacute;rtola beans and procyanidin C1 (PC1) on the inhibition of advanced glycation end products (AGEs) generation in proteins was investigated. SMEE was incubated at 4 degrees C (control) or thermally treated at 60 degrees C for 2 h, at either 0 % O-2 (I) or 20 % O-2 (II). Treatments I and II increased the content of procyanidin dimers B2. Treatment II was more effective than the control or treatment I in preventing homocysteine oxidation and AGEs generation. TT of PC1 at 0 % or 20 % O-2 generated procyanidin dimers and tetramers. PC1 TT at 20 % O-2 exhibited higher oxidation potentials and lower IC50 values of fluorescent AGEs than those of controls or TT at 0 % O-2. These findings indicate that SMEE from T & oacute;rtola beans after treatment II changes the degree of polymerization and oxidation procyanidins, thereby increasing their antiglycation activity.