Browsing by Author "Rodriguez, Jaime"

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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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    Synthesis and Antitumor Evaluation of Thiophene Analogs of Kigelinone
    (BENTHAM SCIENCE PUBL LTD, 2009) Valderrama, Jaime A.; Espinoza, Omar; Rodriguez, Jaime; Theoduloz, Cristina
    The synthesis of kigelinone thiophene analogs and related naphtho[2,3-b] thiophene-4,9-quinones from 2-substituted 4,7-dimethoxybenzo[b]thiophenes via an oxidative deprotection, Diels-Alder, and oxidative aromatization reaction sequence is reported. The 2-substituted naphtho[2,3-b] thiophene-4,9-quinones display significant antitumor activity in the range IC50 1.1-47 mu M on a panel of four distinct human cancer cell lines.