Phenolic profiles and their contribution to the antioxidant activity of selected chickpea genotypes from Mexico and ICRISAT collections.

Chickpea (Cicer arietinum L.) genotypes, nine kabuli from Mexico and 9 desi from other countries, were investigated for their phenolic profiles and antioxidant activity (AA). Phenolics in methanol extracts (ME) were analyzed by ultra-performance liquid chromatography coupled to diode array detection and mass spectrometry (UPLC-DAD-MS), whereas the AA was measured as Trolox equivalents (TE) by ABTS, DPPH and FRAP methods. Twenty phenolic compounds were identified in the ME and their levels showed a great variability among the chickpea genotypes. Phenolic acids and flavonoids were the most abundant compounds in kabuli and desi genotypes, respectively. The AA values (µmol TE/ 100 g dw) by ABTS (278-2417), DPPH (52-1650), and FRAP (41-1181) were mainly associated with the content of sinapic acid hexoside, gallic acid, myricetin, quercetin, catechin, and isorhamnetin, suggesting they are the main compounds responsible for the AA. The sum of the AA obtained for standards of these compounds evaluated at the concentration found in the extracts accounted for 34.3, 69.8, and 47.0% of the AA in the extract by ABTS, DPPH, and FRAP, respectively. In the AA by DPPH, most of the mixtures of these compounds resulted in synergistic interactions. Three desi genotypes with black seeds (ICC 4418, ICC 6306, and ICC 3761) showed the highest AA and flavonoids content, whereas the most promising kabuli genotypes were Surutato 77, Bco. Sin. 92, and Blanoro that showed the highest values of phenolic acids. These genotypes represent good sources of antioxidants for the improvement of nutraceutical properties in chickpea.

Physicochemical and antioxidant characterization of Justicia spicigera.

Extracts with water:ethanol (100:0, 70:30, 50:50, 30:70, 0:100) solutions from fresh (F), just dried (JD), dried and stored for one year (DS) Justicia spicigera leaves were obtained using the stirring and ultrasound techniques. Extracts were analyzed in physicochemical and antioxidant characteristics. Identification of chemical compounds by gas chromatography-mass spectroscopy (GC-MS) was also performed. 2.14±0.91, 5.67±1.70, and 8.52±4.97g Gallic acid equivalents/100g dry weight (d.w.) of phenolic compounds were found, in average, for F, JD, and DS J. spicigera, respectively. 2.22±1.31, 2.58±2.11, and 8.48±3.78g Trolox equivalents/100g d.w. were detected with the ABTS method and 0.49±0.33, 1.23±0.87, and 0.88±0.94g with the DPPH method for F, JD and DS J. spicigera, respectively. Eucalyptol, phytol, and azulene were identified as the main compounds. J. spicigera showed colors (green-iridescent, green-yellow, or pink of different intensities) and antioxidant characteristics depending on the solvent concentration. Extracts could be used in the food and pharmaceutical industries.

SPME determination of volatile aldehydes for evaluation of in-vitro antioxidant activity.

The in-vitro antioxidant activity of natural (essential oils, vitamin E) or synthetic substances ( tert-butyl hydroxy anisole (BHA), Trolox) has been evaluated by monitoring volatile carbonyl compounds released in model lipid systems subjected to peroxidation. The procedure employed methodology previously developed for the determination of carbonyl compounds as their pentafluorophenylhydrazine derivatives which were quantified, with high sensitivity, by means of capillary gas chromatography with electron-capture detection. Linoleic acid and sunflower oil were used as model lipid systems. Lipid peroxidation was induced in linoleic acid by the Fe2+ ion (1 mmol L-1, 37 degrees C, 12 h) and in sunflower oil by heating in the presence of O2 (220 degrees C, 2 h). The change in hexanal (the main lipoxidation product) concentration found in the lipid matrix subjected to oxidation with and without the substance being tested was used to calculate the antioxidant protection effect. These procedures were employed to evaluate the antioxidant activity of the essential oils of cilantro ( Coriander sativum L.), fennel ( Foeniculum vulgare Mill.), rosemary ( Rosmarinus officinalis L.), "salvia negra" ( Lepechinia schiedeana), and oregano ( Origanum vulgare L.), and the well-known antioxidants BHA, vitamin E, and Trolox, its water-soluble analog. In the sunflower oil system, the essential oils had a stronger protective effect against lipid peroxidation than BHA, vitamin E, and Trolox within the range of concentrations examined (1-20 g L-1). The highest protecting effect, corresponding to a 90% drop in hexanal release, was observed for cilantro oil at 10 g L-1.