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Antimicrobial activity of fractions obtained from Mexican oregano (Lippia berlandieri Schauer) chloroform extract was tested by growth inhibition against Escherichia coli, Staphylococcus aureus and Bacillus cereus, and antioxidant capacity was tested by inhibition of linoleic acid oxidation. Fractions were obtained by differences in polarity or structure (phenolic and non-phenolic fraction). Gram-positive organisms were more susceptible to Mexican oregano extracts. Fraction 3 (by polarity) and phenolic fractions I, II, III, IV and V were the extracts with higher antimicrobial activity. The non-phenolic fraction had effect against B. cereus. Polarity fraction 5 and phenolic Fraction II had a high antioxidant capacity; a 0.08% concentration of fraction 5 had a similar effect as butylated hydroxytoluene at 0.01% concentration. Fractions of Mexican oregano with different polarity and functional groups had antioxidant and antimicrobial activity and can be used in a variety of applications.

The stability of antioxidants in extruded and nixtamalized blue maize flours with calcium hydroxide [Ca(OH) 2 ] and calcium lactate [C 6 H 10 O 6 Ca] were evaluated. Extruded blue maize flours batches were obtained by mixing blue maize flours separately with different Ca(OH) 2 (0.1, 0.2 and 0.3 %) and C 6 H 10 O 6 Ca (0.3, 0.6 and 0.9 %) concentrations respectively and extruded to obtain the extruded flours. For nixtamalized flours, the maize grains were cooked at 1 % Ca(OH) 2 and 2.95 % C 6 H 10 O 6 Ca concentrations respectively. Color, antioxidant activity, total phenolics, total anthocyanins and individual anthocyanins, contents were analyzed. Color, antioxidant activity, anthocyanins contents and total phenolics decreased as the calcium hydroxide concentration increased. In contrast, increasing the calcium lactate concentration on the extruded flours had the opposite effect. The extrusion process retained 57-47 %, 72-62 % and 79-65 % of the anthocyanins content, total phenolic content and antioxidant activity, respectively. These retention rates were higher than those of the nixtamalized flours using the same calcium sources. Cyanidin-3-glucoside and pelargonidin-3-glucoside were identified in the maize kernel and flours. Cyanidin-3-glucoside concentration was increased by both extrusion and nixtamalization processed with either of the two calcium sources. In contrast, pelargonidin-3-glucoside concentration decreased by both processes. Other anthocyanins were observed, but they were not identified.

A series of pyrene-fullerene C 60 dyads bearing pyrene units (PyFC 12 , PyFPy, Py 2 FC 12 and PyFN) were synthesized and characterized. Their optical properties were studied by absorption and fluorescence spectroscopies. Dyads were designed in this way because the pyrene moeities act as light-harvesting molecules and are able to produce "monomer" (PyFC 12 ) or excimer emission (PyFPy, Py 2 FC 12 and PyFN). The fluorescence spectra of the dyads exhibited a significant decrease in the amount of pyrene monomer and excimer emission, without the appearance of a new emission band due to fullerene C 60 . The pyrene fluorescence quenching was found to be almost quantitative, ranging between 96%-99% depending on the construct, which is an indication that energy transfer occurred from one of the excited pyrene species to the fullerene C 60 .