Bioactivities of kernel extracts of 18 strains of maize (Zea mays).

Aqueous and ethanolic extracts of maize kernels from 18 varieties/strains were prepared for the evaluation of inhibitory activities toward α-glucosidase and scavenging activities toward nitric oxide (NO•) and superoxide (•O(2)(-)). All ethanolic extracts of maize strains tested inhibited yeast (Saccharomyces cerevisiae) α-glucosidase with the highest potency (49% to 54%) found for 2 purple and a yellow strains. However, inhibitory effects of maize extracts on rat intestinal α-glucosidase were as a whole about 10% as effective as with the yeast enzyme. Maize extracts were capable of scavenging NO• at the level of 0.25 mg/mL to extents ranging from 24% to 50% and 26% to 57%, respectively, for aqueous and ethanolic extracts. All tested aqueous extracts were also capable of scavenging •O(2)(-), with efficacies ranging from 8% to 38%, at the level of 1.5 mg/mL, whereas almost none of the ethanolic extracts scavenged •O(2)(-), except for one purple strain (approximately 10% effective). The effectiveness in the enzyme inhibition and antioxidant assays did not correlate with total phenolic and/or anthocyanin levels, nor with the nature of pigmentation among the maize strains evaluated. Practical Application: A diversity of pigmented maize strains was evaluated for biological activities related to mitigating oxidative stress and slowing down glucose absorption from the diet. Certain strains tended to be more abundant in these biological activities and have potential to be used in dietary regimes that are designed to promote human health.

Betalains, phase II enzyme-inducing components from red beetroot (Beta vulgaris L.) extracts.

Crude aqueous and ethanolic extracts of root tissue of red (Rd) and high-pigment (HP) beet (Beta vulgaris L.) strains exhibited antioxidant and phase II enzyme-inducing activities, and these extracts were fractionated using Sephadex LH-20 chromatography. These bioactivities tended to become co-enriched in early and late eluting fractions, comprising 5-25% of the material recovered from the column. Liquid chromatography-mass spectrometry (MS) was used to resolve and identify multiple betalain components in the most potent quinone reductase (QR)-inducing fractions. Active fractions were found to contain vulgaxanthins I and II, and (iso)betanin, but other components remained unidentified. Two of the isolated active fractions were incorporated into rodent diets at 10-150 ppm over a 2-mo period to assess bioavailability and in vivo efficacy for phase II enzyme induction in various organs. No statistically significant effect of diet was obtained, and wide ranges of tissue enzyme levels among individual animals were observed. This lack of effect and diversity in response to diet may be related to the wide range in absorptive capacity of and/or insufficient level or enrichment of the active agents or to difficulties in assessing such activity in vivo. Subsequent to the animal studies, betanin was isolated in pure form, identified by MS analysis, and confirmed to be QR inducers in the bioassay.

Effects of arginine-containing total parenteral nutrition on N balance and phagocytic activity in rats undergoing a partial gastrectomy.

The present study investigated the effect of arginine (Arg)-containing parenteral nutrition on phagocytic activity to elucidate the possible roles of Arg in the secretion of anabolic hormones and N balance in rats undergoing gastrectomy. Rats were divided into two experimental groups and received total parenteral nutrition (TPN). The TPN solutions were isonitrogenous and identical in nutrient compositions except for differences in amino acid content. One group received conventional TPN, the other group replaced 2 % of the total energy as Arg. After receiving TPN for 3 d, one-third of the rats in each experimental group were killed as the baseline group. The remaining rats underwent a partial gastrectomy and were killed 1 or 3 d after surgery. The results showed that there were no differences in N balance, plasma growth hormone and insulin-like growth factor-1 levels between the two groups before or after surgery. The phagocytic activity of peritoneal macrophages was higher in the Arg group than in the control group 1 d after surgery. There were no differences in the phagocytic activities of blood polymorphonuclear neutrophils between the two groups at various time points. TNF-alpha levels in peritoneal lavage fluid were lower in the Arg group than in the control group on post-operative day 3. These results suggest that parenterally infused Arg enhances phagocytic activity and reduces the production of inflammatory mediators at the site of injury. However, Arg supplementation did not influence the secretion of anabolic hormones nor N balance in rats with a partial gastrectomy.

Effects of glutamine-containing total parenteral nutrition on phagocytic activity and anabolic hormone response in rats undergoing gastrectomy.

AIM: To investigate the effect of glutamine (Gln)-containing parenteral nutrition on phagocytic activity and to elucidate the possible roles of Gln in the secretion of anabolic hormones and nitrogen balance in rats undergoing a gastrectomy. METHODS: Rats with an internal jugular catheter were divided into 2 experimental groups and received total parenteral nutrition (TPN). The TPN solutions were isonitrogenous and identical in nutrient compositions except for differences in amino acid content. One group received conventional TPN (control), and in the other group, 25% of the total amino acid nitrogen was replaced with Gln. After receiving TPN for 3 d, one-third of the rats in each experimental group were sacrificed as the baseline group. The remaining rats underwent a partial gastrectomy and were killed 1 and 3 d, respectively, after surgery. Plasma, peritoneal lavage fluid (PLF), and urine samples were collected for further analysis. RESULTS: The Gln group had fewer nitrogen losses 1 and 2 d after surgery (d1, 16.6+/-242.5 vs -233.4+/-205.9 mg/d, d2, 31.8+/-238.8 vs -253.4+/-184.6 mg/d, P<0.05). There were no differences in plasma growth hormone (GH) and insulin-like growth factor-1 levels between the 2 groups before or after surgery. The phagocytic activity of peritoneal macrophages was higher in the Gln group than in the control group 1 d after surgery (A 1185+/-931 vs 323+/-201, P<0.05). There were no differences in the phagocytic activities of blood polymorphonuclear neutrophils between the 2 groups at the baseline or on the postoperative days. No significant differences in interleukin-1beta or interleukin-6 concentrations in PLF were observed between the 2 groups. However, tumor necrosis factor-alpha level in PLF was significantly lower in the Gln group than in the control group on postoperative d 3. CONCLUSION: TPN supplemented with Gln can improve the nitrogen balance, and enhance macrophage phagocytic activity at the site of injury. However, Gln supplementation has no effect on phagocytic cell activity in the systemic circulation, GH and insulin-like growth factor-1 might not be responsible for attenuating nitrogen losses in rats with a partial gastrectomy.