Soybean extracts enriched with free isoflavones promote nitric oxide synthesis and affect the proliferation of breast adenocarcinoma cells

Although soybean isoflavones naturally accumulate in their conjugated forms, the beneficial effects on human health of soybean-containing foods have been credited to their aglycone forms. In the present study we analyzed the effects of a chemical agent, sodium nitroprusside (SNP), in eliciting the exudation of non-conjugated isoflavones from intact soybean seeds, embrionary axes and cotyledons. The isoflavones in the exudates were determined by high performance liquid chromatography and mass spectrometry. The effect of the exudates on the emission of nitric oxide (NO) and on the proliferation of breast carcinoma cells (MCF-7) was also evaluated. SNP elicitation increased the production of the aglycone forms dose- and time-dependently. Exudates of embrionary axes and cotyledons stimulated NO emission and showed biphasic effects on viability of MCF-7 cells. At lower concentrations both extracts presented proliferative effects (10-25%), and at higher concentrations inhibited (15%) cell proliferation. The biphasic effect might be due to the action of isoflavone aglycones in activating estrogen receptors which in turn stimulate the production of NO. Overall, the results suggest that soybean extracts enriched in isoflavone aglycones by elicitation with SNP could be exploited as a functional ingredient in the food industry.

Evaluation of biomass production, carotenoid level and antioxidant capacity produced by Thermus filiformis using fractional factorial design

A fractional factorial design 2(5-1) was used to evaluate the effect of temperature, pH, and concentrations of yeast extract, tryptone and Nitsch's trace elements on the biomass, total carotenoids and protection against singlet oxygen by carotenoid extracts of the bacterium Thermus filiformis. In addition, the carotenoid composition was determined by high-performance liquid chromatography connected to a diode array and mass spectrometer detectors (HPLC-DAD-MS/MS). The production of biomass ranged from 0.113 to 0.658 g/L, the total carotenoid from 137.6 to 1,517.4 mg/g and the protection against singlet oxygen from 4.3 to 85.1 %. Results of the fractional factorial design showed that temperature had a negative effect on biomass production and a positive effect on carotenoid content and protection against singlet oxygen, besides, high levels of pH value, concentrations of yeast extract and tryptone had a positive effect on biomass production only at lower temperatures. The main carotenoids of T. filiformis were thermozeaxanthins. In the tested conditions, changes in the levels of the variables influenced the biomass, carotenoid production, and protection against singlet oxygen, although they did not influence the carotenoid profile. The results of this study provide a better understanding on the interactions among certain nutritional and cultivation conditions of a thermophile bacterium, Thermus filiformis, on biomass and carotenoid amounts, as well as on the antioxidant capacity.

Análise, por CLAE, de carotenóides de cinco linhagens de Rhodotorula / HPLC analysis of carotenoids from five Rhodotorula strains

Um método por cromatografia líquida de alta eficiência (CLAE) foi otimizado para a análise da composição de carotenóides de cinco linhagens de Rhodotorula. A extração com ruptura mecânica da parede celular da levedura com areia tratada mostrou ser mais eficiente que a ruptura química com dimetilsulfóxido. Os carotenóides foram separados e quantificados por CLAE em coluna de `C IND. 18ï utilizando como fase móvel acetonitrila/metanol (0,1 por cento trietilamina)/acetato de etila (75:15:10) e 100 por cento metanol (0,1 por cento trietilamina) entre as injeções, com vazão de 1 mL/min. Em todas as linhagens, os carotenóides majoritários encontrados foram torularrodina, toruleno, `gamaï-caroteno e ß-caroteno...