Search

Most of the health benefits derived from cereals are attributed to their bioactive compounds. This study evaluated the levels of the bioactive compounds, and the antioxidant and starch-hydrolyzing enzymes inhibitory properties of six pipeline Striga -resistant yellow-orange maize hybrids (coded AS1828-1, 4, 6, 8, 9, 11) in vitro. The maize hybrids were grown at the International Institute of Tropical Agriculture (IITA), Nigeria. The bioactive compounds (total phenolics, tannins, flavonoids, and phytate) levels, antioxidant (DPPH • and ABTS •+ scavenging capacity and reducing power) and starch-hydrolyzing enzymes (α-amylase and α-glucosidase) inhibitory activities of the maize hybrids were determined by spectrophotometry. At the same time, carotenoids were quantified using a reverse-phase HPLC system. The ranges of the bioactive compounds were: 11.25-14.14 mg GAE/g (total phenolics), 3.62-4.67 mg QE/g (total flavonoids), 3.63-6.29 mg/g (tannins), 3.66-4.31% (phytate), 8.92-12.11 µg/g (total xanthophylls), 2.42-2.89 µg/g (total β-carotene), and 3.17-3.77 µg/g (total provitamin A carotenoids). Extracts of the maize hybrids scavenged DPPH • (SC 50 : 9.07-26.35 mg/mL) and ABTS •+ (2.65-7.68 TEAC mmol/g), reduced Fe 3+ to Fe 2+ (0.25 ± 0.64-0.43 ± 0.01 mg GAE/g), and inhibited α-amylase and α-glucosidase, with IC 50 ranges of 26.28-52.55 mg/mL and 47.72-63.98 mg/mL, respectively. Among the six clones of the maize hybrids, AS1828-9 had the highest ( p < 0.05) levels of tannins and phytate and the strongest antioxidant and starch-hydrolyzing enzymes inhibitory activities. Significant correlations were observed between total phenolics and the following: ABTS •+ ( p < 0.01, r = 0.757), DPPH • SC 50 ( p < 0.01, r = -0.867), reducing power ( p < 0.05, r = 0.633), α-amylase IC 50 ( p < 0.01, r = -0.836) and α-glucosidase IC 50 ( p < 0.05, r = -0.582). Hence, the Striga -resistant yellow-orange maize hybrids (especially AS1828-9) may be beneficial for alleviating oxidative stress and postprandial hyperglycemia.

Effects of fluoride on the levels of Lipid peroxidation (LP) and antioxidant enzymes in the brain regions of protein undernourished (PU) and well-fed rats (WF) rats exposed to 100 ppm fluoride in drinking water were investigated. The results indicate that the mean body weights and the total brain weights of PU rats as well as those given fluoride (both WF and PU) were significantly (P < 0.05) lower than their respective controls. The weights of different brain regions were also significantly reduced (P < 0.05) in PU rats compared to WF rats except in the brain stem. Fluoride ingestion diminished the weights of WF and PU rats affecting the cerebrum only (in the case of PU rats) and the cerebellum of both WF and PU rats without an effect on the brain stem of both WF and PU. Additionally, increased LP was observed in the cerebrum and cerebellum of PU rats but after fluoride ingestion, 30% increase in LP was observed only in the cerebrum. In the brain stem however, protein undernutrition was accompanied with a significant reduction in LP but the region seems insensitive to fluoride. There were significant reductions (P < 0.05) in CAT, SOD and GSH in all the brain regions (except the GSH level in the brain stem only) of PU rats. Fluoride induced reduction in the activity of CAT in the three brain regions and on SOD activity in cerebrum only for WF rats but no effect of fluoride on all the antioxidants studied in the three brain regions for PU rats. It is concluded that WF and PU rats responded differently to fluoride toxicity. However, it seems that at the dosage used, fluoride toxicity may be a direct effect on the antioxidant enzymes., (Copyright © 2013 Elsevier GmbH. All rights reserved.)