Browsing by Subject "Antioxidants"
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Item A combination high in antioxidant foods’ effects on blood antioxidant and oxidative stress levels in post-menopausal women(2011-08) Kloiber, Shelby; Hart, Melanie A.; McComb, Jacalyn J. R.; Park, YoonjungOxidative stress brought on by free radicals can lead to an increased risk of certain diseases such as heart disease and some cancers. Oxidative stress mediated damage can be reduced by scavengers, or antioxidants that can eliminate the high reactivity of free radicals by turning them into non-radical and nontoxic metabolites. Many scientists have investigated the effects of different kinds of foods (whole, liquid, or supplement) to measure the change in oxidative damage and antioxidant capacity. The purpose of this study is to examine the effects of two types of foods high in antioxidant on markers of oxidative stress and antioxidant capacity in postmenopausal women. Healthy post-menopausal women, (N=16) were divided into four groups (i.e., fruits, soymilk, fruits and soymilk and control). Oxidative stress and antioxidant capacity were measured before and after the intervention. Oxidative stress results indicated no significant differences. Antioxidant capacity results indicated a significant main effect for Test with the mean for the pre-test (M = 0.28 units/ml, SD = 0.15) being significantly lower than the mean for the post-test (M = 0.39 units/ml, SD = 0.23). The results from this study did not support the effectiveness of fruits and soymilk on the oxidative stress levels and antioxidant capacity in postmenopausal women.Item An evaluation of the antioxidant properties of grain sorghum(Texas Tech University, 1972-12) Wong, Mee ChengNot availableItem Antioxidant-Essential Oil Gel as a Treatment for Gingivitis in Orthodontic Patients(2014-04-22) Martin, Benjamin JohnThe purpose of this study was to evaluate the treatment effect of an antioxidant-essential oil gel on orthodontic patients with generalized gingivitis. The gel contains the essential oils menthol and thymol, and the antioxidants ferulic acid and phloretin. Thirty patients from the Texas A&M University Baylor College of Dentistry orthodontic clinic were screened for gingivitis, and randomly allocated into treatment and placebo-control groups. Each patient was evaluated at three orthodontic treatment visits (T1, T2, and T3). A periodontal examination, including probing depths (PD), bleeding on probing (BOP), gingival index (GI), and plaque index (PI) was performed at each visit. Between T1 and T2, patients were instructed to apply a topical gel (active or placebo) to their gingiva twice daily, after brushing. From T2 to T3 patients were instructed to discontinue use of the gel. The treatment group showed statistically significant (p<.05) reductions of BOP (- 13.6 percentage points) and GI (-0.14) between T1 and T2, and significant increases in BOP (13.3 percentage points) and GI (0.14) between T2 and T3. Except for an increase in the GI between T2 and T3, the control group showed no significant changes in BOP or GI over time. The only other significant changes that occurred pertained to the treatment group, which showed significant increases in PD (0.08mm) and PI (0.18) between T2 and T3. Application of a topical antioxidant-essential oil gel is an effective means of reducing inflammation in orthodontic patients with gingivitis.Item Composition, antioxidant properties and microbiology of nutmeg ground by three procedures(Texas Tech University, 1990-05) McKee, Lisa HarrisonComposition, antioxidant capacity, and microbial loads of nutmeg ground by ambient, chilled, and liquid nitrogen methods were studied. The particle size (modulus of fineness) and the percentage of moisture were not different (P>0.05) between the three types of ground nutmeg. The percentage of steam volatile oil in nutmeg ground by the ambient method (5.8%) was different (P<0.05) from that of nutmeg ground under colder conditions (chilled and liquid nitrogen, 5.4%). The percentage of steam volatile oil in nutmeg ground by the chilled method (5.5%) was not different (P>0.05) from that of nutmeg ground by the liquid nitrogen method (5.3%). An interaction between grinding method and batch was detected for percentage of oleoresin. The oleoresin color equivalent of nutmeg ground by the chilled method (0.748 g/100 ml) was different (P<0.05) from that of nutmeg ground by the liquid nitrogen method (0.969 g/100 ml). The oleoresin color equivalent of nutmeg ground by the ambient method (0.902 g/100 ml) was not different from that of nutmeg ground under colder conditions (chilled and liquid nitrogen, 0.859 g/100 ml). The addition of 2.5% nutmeg was found to have a slight antioxidant effect when tested in a model salad dressing. Antioxidant capacity was not different (P>0.05) between the three types of ground nutmeg. Standard plate counts were not different (P>0.05) between the three types of ground nutmeg. Yeast and mold loads were different (P<0.05) between the three types of ground nutmeg. Nutmeg ground by the ambient method tended to have higher microbial loads than that ground by either chilled or liquid nitrogen methods.Item Dietary fat and antioxidant status relating to colon carcinogenesis(Texas Tech University, 1993-05) Tsai, Shwu-yarEpidemiological evidence has linked dietary fat with colorectal cancer in humans but with mixed results. Studies using animal models have shown that high fat diets containing predominantly corn oil, beef tallow or lard induce colon tumorigenesis to a greater extent than corresponding low fat diets; however, these findings are still inconclusive. Recently, some research indicated differences according to the types of fat used and support the concept that diets high in unsaturated fatty acids have a greater tumor-promoting capability than diets high in saturated fatty acids. The mechanism was proposed that free radicals were involved in colon carcinogenesis. Therefore, a polyunsaturated fatty acid (PUFA) diet would increase antioxidant activity to prevent free radical damage. Several studies have indicated that dietary lipids influence the liver microsomal mixed function oxidase system. It has been reported that the elevation of dietary polyunsaturated fatty acid intake increases the activity of the liver microsomal enzymes responsible for carcinogen metabolism. Some studies directed the diet-related effect on the susceptibility of colonic cells to nuclear-damaging agents. However, there have been very few studies on the effects of dietary fat and nuclear aberrations due to xenobiotics challenge. The purpose of this study was to examine the effect of amount and type of dietary fat on the (1) colon mucosal antioxidant status; (2) liver microsomal demethylase activity; (3) liver microsomal and cytosolic mutagenic activation; and (4) colonic epithelial nuclear aberrations during colon carcinogenesis.Item Effect of antioxidants on the mutagenic activation of N(OH)AcAF by corn oil(Texas Tech University, 1978-08) Thomas, James NealNot availableItem Effects of antioxidants on visual and palatability attributes of hot and cold processed pork loin chops.(Texas Tech University, 1984-05) Clarke, Andrew DouglasNot availableItem Effects of dietary fat and dimethylhydrazine on rat colonic antioxidant status: implications for carcinogenesis : a dissertation in home economics(Texas Tech University, 1991-08) Kuratko, Connye J. N.Previous studies have shown that the composition of membrane phospholipids reflects the fatty acid composition of the diet. Membranes that contain a high proportion of polyunsaturated fatty acids (PUFA) are potentially more susceptible to attack by free radicals. Radicals are reactive chemical species that contain one or more unpaired electrons. Oxygen and some of its metabolites are radicals that are highly reactive, potentially toxic to the cell, and have been implicated in a variety of disease processes. Double bonds within PUFA participate in reactions with these radicals and propagate their formation. Cells contain protective antioxidant mechanisms including superoxide dismutase (SOD), glutathione peroxidase (GSHPx), catalase (CAT), glutathione (GSH), glutathione reductase (GSSGRx), glutathione-S-transferase (GST) among others. Cellular damage results as these mechanisms become depleted. The effects of dietary fat on these antioxidant mechanisms in colon mucosa were examined using male Sprague-Dawley rats. Animals were fed one of four AIN 76A-based test diets differing in amount and type of lipid. The basal diet (BD) contained 5% corn oil; the menhaden oil diet (MO) contained 1% corn oil and 19% menhaden oil; the corn oil diet (CO) contained 20% corn oil; and the beef tallow diet (BT) contained 1% corn oil and 19% beef tallow; all were adjusted to provide equal amounts of other nutrients. Homogenates of colon mucosa were assayed after 2 weeks, 1, 3, 6 and 9 months for activities of CAT, GSHPx, SOD, GST, GSSGRx, and total GSH content. In the first objective of this study, measurements were made at the various time points in rats fed test diets to determine whether diets high in polyunsaturated fatty acids (PUFA) would produce an increased demand on antioxidant activity in colon mucosa. Beginning at the 2-week time point GSH, GSSGRx, and SOD showed differences due to diet. At 1 month only GST showed differences. Then, at the 3-month point, GSH, GSSGRx, GSHPx, and at the 6-month point, GST, SOD, GSHPx and CAT, respectively, were affected. By the 9-month time point, only CAT showed differences due to diet. Both the type and amount of fat in theItem Flavonoid composition and antioxidant activity of pigmented sorghums of varying genotypes(2009-05-15) Dykes, LindaA wide variety of sorghum genotypes with a pigmented pericarp were grown in varying environments and were analyzed for total phenols, condensed tannins, flavan-4-ols, and in vitro antioxidant activity. In addition, sorghum flavonoids were separated, characterized, and quantified using HPLC-PDA and LC-MS. Total phenols and in vitro antioxidant activity increased when sorghums had a pigmented testa causing the presence of condensed tannins. Flavan-4-ol levels were highest in sorghums with a black pericarp (5.8-16.1 abs/mL/g), followed by those with a red pericarp (1.1-9.2 abs/mL/g). Sorghums with a black pericarp had the highest 3-deoxyanthocyanin levels (308-1885 ?g/g) and these were increased when the grain had minimal weathering and was darkest in color. Sorghums with a lemon-yellow pericarp had the highest flavanone levels (260-3586 ?g/g) with eriodictyol being the main flavanone. Flavanone levels were increased when the grain was bright yellow with minimum weathering and were high compared to those found in common sources (238-574 ?g/g, fresh wts.). No flavonoids were predominant in sorghums with a red pericarp. Flavonoid composition varied when all sorghums were grouped by secondary plant color. Sorghums with tan secondary plant color, including those with a white pericarp, had higher levels of flavones (50-932 ?g/g) than those with red/purple secondary plant color (0-172 ?g/g). On the other hand, 3-deoxyanthocyanin levels were higher in red/purple plant sorghums (14-1885 ?g/g) than in tan plant sorghums (0-24 ?g/g). Among red/purple plant sorghums, lemon-yellow pericarp sorghums had the highest levels of flavones (51-172 ?g/g). Environment and weathering had an effect on flavonoid levels. The 3-deoxyanthocyanins were reduced for sorghums grown in a dry environment (i.e. Lubbock, TX) and flavonoid levels were increased in grains with minimum weathering or molding. This study reports that all sorghums, including those with a white pericarp, have flavonoids and their levels and compositions are affected by the genotype. This information will be helpful for plant breeders, food scientists, and the pharmaceutical/nutraceutical industries in selecting sorghums with desired healthy components.Item Influence of Ascophyllum nodosum on selenium and antioxidants in beef cattle(Texas Tech University, 2001-12) Cradduck, Will C.Tasco, a proprietary product derived from a brown kelp {Ascophyllum nodosum). has altered antioxidants in plants and animals. Selenium (Se) is a component of glutathione peroxidase, a cellular antioxidant, which is closely related to vitamin E in activity. Antioxidants have been implicated in the improved immune fiinction of steers and shelf life of the meat from steers that grazed pastures treated with Tasco. Therefore, experiments were conducted to determine the effects of Tasco products on Se concentrations in forage and cattle. In Experiment 1. Tasco-Forage (a water-soluble extract) was applied (3.5 kg/ha in April and July) to endophyte Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin) -infected and endophyte-free tall fescue {Festuca arundinacea) grazed by Angus steers in Virginia during 1995 (initial mean BW 245 kg; SD = 20), 1996 (initial mean BW 234 kg; SD = 9), and 1997 (initial mean BW 265 kg; SD = 5). Tasco tended (P = 0.11) to decrease Se in endophyte-infected tall fescue and increased (P < 0.05) Se in endophyte-free tall fescue (interaction; P < 0.05) when averaged over years and dates. By the end of the grazing season, steers that grazed Tasco-treated fescue had higher (P < 0.05) Se in serum (1996) and whole-blood (1997) than steers that grazed non-treated fescue, regardless of the endophyte. Endophyte-infected tall fescue decreased (P < 0.05) serum Se (1996) and whole-blood Se (1997) compared with non-infected fescue. At the end of grazing, steers were finished on a feedlot in Texas. No differences in serum Se were observed following feedlot fmishing. In Experiment 2, Tasco-14 (a meal from dried, ground, intact A. nodosum) was fed (0, 1.5, or 3.0% of diet, DMB) to crossbred steers (Trial 1 initial mean BW = 332 kg, SD = 37; Trial 2 initial mean BW = 340 kg, SD = 18) during a 127-d eedlot finishing period. Steers were fed a diet based on steam-flaked com {Zea mays L.: Trial 1) or steam-flaked milo {Sorghum bicolor; Trial 2). No differences in serum Se were observed by harvest, but liver Se decreased linearly (P < 0.05) at harvest as a result of Tasco treatment in Trial 2. In Experiment 3, Tasco-EX fed to steers for the final 2-wk in the feedlot, at 0, 1, and 2% of the dietary DM had no effect on serum Se but linearly (P < 0.05) decreased serum vitamin A. Serum vitamin E of steers fed 1% Tasco did not increase as much as controls (P < 0.05) over the 2-wk period. Vitamin A, E, and Se were not affected in liver. In Experiment 4, sale bam heifers were supplemented (90 g d"' target consumption) with Tasco-EX in the drinking water for a 2-wk period. No effect on serum Se was observed at the end of the 2-wk supplementation period as a resuh of Tasco treatment. In Experiment 5, Tasco-14 was fed (0.18 kg hd'' d'') to Angus-crossbred (initial mean BW = 238 kg, SD=18) steers for 2-wk before transport to the feedlot, and for 2-wk after arrival. No effect of Tasco treatment on semm Se was observed immediately before or immediately after transport. No effect on whole-blood Se was observed 2-wk after transport. Tasco increased blood Se in grazing steers, but changes in blood Se only partially reflected differences in forage Se. Effects of Tasco on forage Se concentration depended on the presence of the endophyte. Application of Tasco to forage in Se deficient regions might improve Se status of grazing livestock. Presence of the endophyte decreased Se in the animal but not in the forage. Direct feeding of Tasco to steers did not aher serum Se, but decreased liver Se with long-term feeding and depressed serum vitamin A and E with short-term feeding. Treatment of beef heifers with Tasco in the drinking water did not aher serum Se. Tasco increased Se concentrations in endophyte-free tall fescue forage from Se deficient areas, but not endophyte-infected tall fescue. Other mechanisms working through the forage that are not totally understood, as well as ahered Se concentration of the forage, might provide an altemative to direct Se supplementation in deficient areas by increasing the Se status of cattle grazing both endophyte-infected and endophyte-free tall fescue.Item Interaction of simvastatin and aerobic exercise on expression of mitochondrial and cardioprotective proteins in skeletal and cardiac muscle tissue(2006-05) Meaney, Mary Patricia; Starnes, Joseph W.Simvastatin is a cholesterol-lowering drug designed to lower cholesterol by inhibiting HMG-CoA reductase, the rate-limiting enzyme of cholesterol synthesis. Statins also inhibit the production of coenzyme Q (CoQ), which shares the same biosynthetic pathway. CoQ is an essential part of the mitochondrial electron transport chain (ETC) and has antioxidant properties. In addition, statins have been shown to effect the expression of antioxidant enzymes and heat shock proteins. Aerobic exercise has also been shown to have an effect on the aforementioned proteins. Statins and aerobicexercise are often co-prescribed by physicians even though the interaction of statins and exercise in heart and skeletal muscle has not been adequately explored. Purpose: To determine the interaction of simvastatin and exercise on CoQ, catalase (CAT), glutathione peroxidase (GPx), Manganese superoxide dismutase (Mn SOD), and heat shock protein 70 (HSP70) in cardiac muscle tissue and the expression of CoQ in the plantaris. Methods: Female 4-mo-old Sprague-Dawley rats were randomly assigned to four treatment groups (N = 15-18/group): sedentary (SED), sedentary treated with simvastatin (SED+SIM), exercise trained (EX), and exercise trained treated with simvastatin (EX+SIM). Rats assigned to simvastatin treated groups received 10 mg simvastatin (Zocor®)/kg body/eight/day for four weeks. Rats assigned to exercise groups were exercised on a treadmill five days/week for four weeks at about 70% VO2max for a duration that was gradually increased to 60 minutes/day. Twenty-four hours after the last session, the animals were euthanized and the heart and both plantaris muscles were removed. Some hearts were perfused for 20 minutes to rinse away blood and others were subjected to an ischemia-reperfusion (I-R) protocol. Left ventricles of IR hearts and the left plantaris were homogenized in ddH2O and lipids were extracted and analyzed for CoQ by high performance liquid chromatography. CAT, GPx, and Mn SOD activity was measured polarographically and HSP70 expression was determined by western blotting of the supernatant of homogenate from the left ventricular tissue of rinsed hearts. Results: A simvastatin main effect was observed on CoQ expression of cardiac and skeletal muscle, and CAT activity of cardiac muscle tissue. Expression of CoQ was decreased while CAT activity was increased following statin treatment. An exercise main effect was observed on CoQ and HSP70 expression of cardiac muscle tissue. Exercise decreased CoQ expression, but increased HSP70 expression in the heart. An interaction effect was observed on both HSP70 expression and Mn SOD activity of cardiac tissue. With respect to HSP70, treatment with simvastatin slightly attenuated an exercise induced increase in HSP70 expression. With respect to Mn SOD, treatment with simvastatin or exercise decreased activity while a combined treatment restored Mn SOD activity to a level similar to that of animals who received no treatment. Conclusion: Treatment with simvastatin or exercise alone results in alterations in the expression of CoQ and HSP70 and activity of CAT, GPx, and Mn SOD. With co-administration, simvastatin and aerobic exercise interact in such a way that maintains one's antioxidant defenses despite impairment the body's ability to synthesize CoQ.Item Protection against UVB-induced damage to keratinocytes by antioxidant nutrients(Texas Tech University, 1996-05) Stewart, MarjoryThe ultraviolet component of sunlight causes increases in reactive oxygen species, and to the extent that these species exceed the ability of antioxidant defenses to remove them, oxidative damage occurs. Antioxidant systems have evolved to protect organisms from endogenous and exogenous reactive oxygen species — in humans these systems are enzymatic and non-enzymatic, and the non-enzymatic systems include certain nutrients. Evidence from biological and epidemiological studies suggests that vitamins C, E, B-carotene and selenium have useful roles in chemoprevention. 8-OHdG is an oxidative DNA lesion that can be sensitively measured as an index of oxidative stress in cells, using HPLC coupled with ultraviolet and electrochemical detection. These lesions can lead to transversion mutations and can therefore potentially contribute to skin cancer. Using Balb/c MK-2 cells the level of 8-OHdG residues, normalized to normal dG residues, was measured following UVB exposure for keratmocytes grown in several nutrient-specific media. UVB doses from 4-500 mJ/cm increased the level of adducts for cells grown m EMEM, but with supplementation of 5 pg/mL selenite, 0.8 pg/mL ascorbate, or 20 pg/mL trolox (a vitamin E analog), the level of adducts was reduced to the level seen in unirradiated controls. Within 24 hours of a 500 mJ/cm^2 UVB insult, the activity of antioxidant enzymes superoxide dismutase and catalase increased; the level of induction or activity increase was greatest for cells grown with the lowest levels of antioxidant nutrients. This suggests some complementarity for enzymatic and non-enzymatic defenses. Cell culture medium contains little or no selenium, and glutathione peroxidase is consequently very low unless cells are supplemented. With supplementation there is an increase in glutathione peroxidase, but the level of this enzyme is unchanged by increasing Se to concentrations five times greater. P53 constitutively arrests the cell cycle to allow repair of damaged DNA. Immunoblots of protem from cells pre-incubated with supplemental nutrients showed little difference across treatment. Immunoblotting for bcl-2, a protein that inhibits apoptosis, showed a greater that 5x stronger band for Se-treated cells than for the negative control. Collectively these data show that the ultraviolet component of sunlight causes damage that is free-radical mediated, and that some of this damage can be reduced by antioxidant nutrients.Item Relationships among antioxidants, phenolics, and specific gravity in potato cultivars, and evaluation of wild potato species for antioxidants, glycoalkaloids, and anti-cancer activity on human prostate and colon cancer cells in vitro.(2009-05-15) Nzaramba, Magnifique NdambeUnderstanding the influence of environment and correlation/relationships among traits is necessary in selection for crop quality improvement. Therefore, correlations among antioxidant activity (AOA), total phenolics (TP), phenolic composition, and specific gravity (SPG) in four potato (Solanum tuberosum, L.) cultivars (Atlantic, Red La Soda, Russet Norkotah, and Yukon Gold) grown in nine states (California, Idaho, Michigan, Minnesota, New Jersey, North Carolina, Oregon, Texas, and Wisconsin) for three years, and in 15 advanced selections grown in Texas were investigated. Cultivars within and between locations were significantly different in AOA, TP, and SPG. Significant effects of cultivar, year, location and their interactions on AOA, TP, and SPG were observed. There were significant positive correlations among the four cultivars between AOA and TP, and negative correlations between AOA and SPG, and between TP and SPG. However, correlations between AOA and SPG, and between TP and SPG, in the advanced selections were not significant. Some tuber-bearing wild potato species were higher in AOA and TP than the commercial cultivars; therefore, they could be used as parental material in breeding for high AOA and TP. However, use of wild species that might be higher in total glycoalkaloids (TGA) than cultivars could result in progenies with high TGA if the traits are positively correlated. To elucidate the relationships among AOA, TP and TGA, accessions of Solanum jamesii and S. microdontum from the US Potato Genebank were screened for these traits and their correlations determined. Also, anti-proliferative and cytotoxic effects of 15 S. jamesii tuber extracts (5 and 10 ?g/ml) on human prostate (LNCaP) and colon (HT-29) cancer cells was determined in vitro. Alpha-solanine and ?-chaconine were found in both species, while tomatine and dehydrotomatine were quantified in some S. microdontum accessions. Both species were higher in all above traits than the Atlantic, Red La Soda, and Yukon Gold cultivars. More than 90% of S. jamesii accessions had TGA levels < 20 mg/100g fresh weight, while only two accessions of S. microdontum, P1 500041 and PI 473171, exhibited TGA < 20 mg/100g. Neither AOA nor TP was significantly correlated with TGA in both species. Also, individual phenolics were not correlated with TGA. Solanum jamesii accessions significantly reduced proliferation of HT-29 (5 and 10?g/ml) and LNCaP (10?g/ml) cells and were not cytotoxic compared to the control (DMSO). Therefore, since AOA and TP were not found to be correlated with TGA, using wild accessions in breeding for increased health promoting compounds would not necessarily increase glycoalkaloids in newly developed potato cultivars.Item The effect of seaweed (Ascophyllum nodosum) extract on antioxidant activities and drought tolerance of tall fescue (Festuca arundinacea schreb.)(Texas Tech University, 1998-08) Ayad, Jamal YousefPlants have developed enzymatic and nonenzymatic antioxidant mechanisms to prevent oxidation of cellular compartments. Enhancing these mechanisms might help plants cope with encountered stresses. Greenhouse and field studies were conducted to examine the influence of seaweed(Ascophyllum nodosum) extract on antioxidant enzymes activities, forage growth, and persistence of tall fescue (Festuca arundinacea Schreb.). Furthermore, effects of soil moisture, plant genotype, and infection with the endophyte Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon and Hanlin) were investigated. In a greenhouse experiment, seaweed extract was applied to 'Martin' tall fescue at 0, 2, 4, 6, 8, and 10 kg ha^-1 in a randomized block design with four replicates. Seaweed extract linearly increased (P <0.05) glutathione reductase activity. Superoxide dismutase and ascorbate peroxidase were also increased but responses differed by time and treatment rates. In a second greenhouse experiment, seaweed extract was applied at 4 kg ha^-1 to endophyte-infected and non-infected 'Georgia Jessup' and 'KY-3r tall fescue grown with 50-100% and 30-100% field capacity soil moisture in a completely randomized design with four replications. Glutathione reductase activity increased (P < 0.05) in both genotypes in response to seaweed extract and moisture stress and tended to increase (P < 0.07) in response to the endophyte. Seaweed extract increased (P < 0.05) superoxide dismutase activity in both genotypes under water stress. Endophyte infected and non-infected KY-31 tall fescue were grown in a 2-yr field experiment, to investigate effects of 4 kg seaweed ha^-1 and three levels of irrigation to replace 0, 50,100% of potential evapotranspiration in a randomized block design with four replications. Superoxide dismutase, glutathione reductase, and ascorbate peroxidase activities were increased (P < 0.05) in response to seaweed extract, presence of the endophyte, and increased linearly (P < 0.05) in response to increased moisture stress. Plant growth and yield did not appear to be affected by seaweed extract at the applied rates. Results indicated that seaweed extract increased tall fescue antioxidant enzyme activities and may provide a tool for manipulating the antioxidant system in plants for increased protection against active oxygen species.