2006 Publications

Objective: An experiment evaluated the effect of citrus juice on enhancing serum antioxidant status and on osteoposis prevention in orchidectomized rats. Methods: Thirty-six 1-y-old male rats were randomized to two groups: a sham-control group (n = 9) and an orchidectomized group (n = 27). The orchidectomized group was divided into three groups of nine and assigned to one of the following treatments: orchidectomy, orchidectomy plus orange juice, and orchidectomy plus grapefruit juice. Sixty delays after initiation of the study, all rats were killed, blood was collected, and serum was harvested for total antioxidant status and indices of bone formation and resorption. Femoral density and biomechanical properties were monitored. Results: Orchidectomy decreased (P <0.05) total antioxidant capacity, femoral density, and biomechanical properties and increased (P < 0.05) alkaline phosphatase, acid phosphatase, and urinary excretion of hydroxyproline compared with the sham-control group. In contrast to orchidectomy, orchidectomy plus orange juice and orchidectomy plus grapefruit reversed (P < 0.05) orchidectomy-induced antioxidant suppression, decreased (P < 0.05) alkaline phosphatase and acid phosphatase activities, moderately restored (P = 0.07) femoral density, increased (P < 0.05) femoral strength, significantly delayed time-induced femoral fracture, and decreased (P < 0.05) urinary excretion of hydroxyproline. Conclusion: The present study supports the supposition in that drinking citrus juice positively affects serum antioxidant status and bone strength.

Oxidative stress and hypogonadism are two factors linked to the increased incidence of cardiovascular disease in males. Eating fruits and vegetables is known to reduce the incidences of oxidative stress. The objective of this research was to delineate whether drinking daily squeezed orange juice (OJ) or grapefruit juice (GJ) modulates oxidative stress and antioxidant enzymes while impacting cardiovascular risk factors in hypogonad male rats. In the present study, 36 1-year-old male rats were equally divided among the following four treatments: sham (control), orchidectomized (ORX), ORX + OJ, an and ORX + GJ. After 60 days of drinking OJ or GJ, antioxidant capacity, cholesterol, and triglycerides in serum and superoxide dismutase (SOD), catalyase (CAT), cholesterol, and triglycerides in liver were evaluated. Serum antioxidant capacity and SOD and CAT activities decreased (P < .05), while serum cholesterol and liver triglycerides increased (P < .05) in the ORX group compared with the sham group. In contrast to the ORX group, drinking OJ was ineffective while drinking GJ decreased (P < .05) triglyceride concentration in liver and increased (P < .05) serum antioxidant capacity and SOD and CAT activities compared with the ORX group. In conclusion, drinking OJ or GJ prevented oxidative stress by enhancing total antioxidant capacity and elevating liver antioxidant enzymes while modulating cardiovascular risk factors.

Bioactive compounds present in grapefruit juice are known to increase the bioavailability of certain medications by acting as potent CYP 3A4 inhibitors. An efficient technique has been developed for isolation and purification of three furocoumarins. The isolated compounds have been tested for the inhibition of human CYP 1B1 isoform using specific substrates. Grapefruit juice was extracted with ethyl acetate (EtOAc) and the dried extract was loaded onto silica gel column chromatography. Further, column fractions were subjected to preparative HPLC to obtain three compounds. The purity of these compounds was analyzed by HPLC and structures were determined by NMR studies. The identified compounds, bergamottin, 6′,7′-dihydroxybergamottin (DHB), and paradisin-A, were tested for their inhibitory effects on hydroxylase and O-dealkylase activities of human cytochrome P450 isoenzymes CYP 3A4 and CYP 1B1. Paradisin-A was found to be a potent CYP 3A4 inhibitor with an IC50 of 1.2 μM followed by DHB and bergamottin. All three compounds showed a substantial inhibitory effect on CYP 3A4 below 10 μM. Inhibitory effects on CYP 1B1 exhibited a greater variation due to the specificity of substrates. Paradisin A showed an IC50 of 3.56 ± 0.12 μM for the ethoxy resorufin O-dealkylase (EROD) activity and 33.56 ± 0.72 μM for the benzyloxy resorufin (BROD). DHB and bergamottin showed considerable variations for EROD and BROD activities with an IC50 of 7.17 μM and 13.86 μM, respectively.

Areas with mild climate conditions are suitable for growing winter spinach (Spinacia olcracea L.). Successful production depends on choosing slow-bolting cultivars resistant to major diseases in each area. Field experiments with a total of 18 cultivars were conducted during 8 years in the Winter Garden region of Texas, an area known for its high white rust (Albugo occidentalis G. W. Wils) inoculum. Spinach cultivars differed widely in their resistance to both white rust and bolting, and the incidence of both traits was more severe as the season progressed. White rust infection increased linearly with average monthly minimal air temperature. Cultivars Fidalgo, Springfield, and Springer were slow bolting and are suitable for areas with no white rust incidence, which cvs. ASR-318, DMC 66-09, Fall Green, Samish, and San Juan were more white rust resistant.

Single- and double-row arrangements of a fixed population (one plant every 0.285 m2) were compared in factorial combination with two (2002) or five (2003) cultivars for effects on yield and fruit quality of bell pepper (Capsicum annual.). Arrangements for 2002 were S30, single row 0.95 m apart, plants within rows 30 cm apart; D30, 1.9 m between centers of double-row beds, double row 30 cm apart on beds, plants within rows 30 cm apart; S37.5 cm apart. Only the S30 and D30 arrangements were used in 2003 after 2002 results showed almost no differences between S30 and S37.5 or between D30 and D37.5. Choice of cultivar was more critical in Texas, where 'X3R Wizard' consistently outperformed 'King Aruth', than in Oklahoma. Single rows resulted in more full-season total marketable fruit weight than double rows in three experiments out of four, primarily as a result of an increased weight of U. S. No. 1 fruit were single rows. Average weight per marketable fruit was consistently unaffected by plant arrangement. Single rows also resulted in a greater full-season weight of sunburned fruit than double rows in two experiments out of four. Cultivar ´ plant arrangement interactions were not evident in Oklahoma and never involved full-reason marketable fruit weights at either location in either year. Given the tested population, a single-row arrangement is likely to result in increased full-season production of U.S. No. 1 bell pepper fruit compared with a double-row arrangement, despite an increased potential for sunburned fruit with single rows.

Bulb color in onions (Allium cepa) is an important trait, and homogenous red coloration is desirable in red onion cultivars. The gene encoding anthocyanin synthase (ANS) is required for anthocyanin biosynthesis in onions. We have previously described three different alleles of the ANS gene. Here we report identification of the fourth allele of ANS, ANS-hl, found in a dark red doubled haploid line. ANS-hl is similar to a non-functional allele found inBrazilian yellow cultivars except that it has several point mutations and indels throughout the promoter and coding regions, none of which are predicted to inactivate enzymatic activity. F2 and backcross populations originating from the crosses between wild-type (ANS-L) allele-containing red and pink (ANS-p) allele-containing white or yellow parents show a discrete segregation ratio of 3 red to 1 light pink, indicating that the wild-type allele is completely dominant over the pink allele. In contrast, segregating populations derived from the crosses between ANS-hl allele containing red and the same white or yellow parents show a gradient of red intensity from light pink to dark red, suggesting that other genetic factors may affect expression of ANS-hl. A newly developed PCR-based marker and two previously developed markers for allelic selection of the ANS gene were used to examine allele composition in fifty-six breeding lines and commercial cultivars. Most lines are heterogeneous for the ANS gene with two or three alleles detected. The frequency of the pink allele is low in red breeding lines, but it is predominant in white and yellow lines.

The aim of this study was to determine whether aminoethoxyvinylglycine (AVG), an inhibitor of ethylene synthesis, would affect earliness, increase yield, and improve overall at harvest and postharvest quality of melon (Cucumis melo L. group Cantalupensis, 'Sol Real'). Field experiments were conducted during two seasons with AVG (124 g ha-1 a.i. ) applied as spray or soil injected into the root zone with a single or double application between 7 d and 21 d before harvest. The AVG soil injection method increased earliness compared with AVG spray in one season. Total marketable yield increased with AVG injection but not with the AVG spray method compared with the control. Regardless of method of application, AVG did not affect fruit firmness, rind thickness, netting, or soluble solids content when measured at harvest. However, AVG spray decreased fruit size and seed cavity in one season. Similarly, AVG spray did not affect fruit quality after storage, whereas AVG soil inject injection increased fruit firmness. Overall, melon yield and fruit quality responses to preharvest AVG applications were superior for the soil inaction than the spray method.

Two commercial muskmelon varieties 'Caravelle' and 'Primo') were grafted on Cucurbita and Cucumis rootstocks and grown in fields with a history of vine decline disease caused by Monospororascus cannonbullusto determine whether physiological responses of the scions are consistent with predictions of a high capacity of water uptake by the rootstocks. Three Cucurbita (hybrid squashes: HS 380, HS 286, and HS 1330) and six Cucumis (PI 20488, PI 1207, MRI, PI 212210, PI 124104, and hybrid melon 3105) rootstocks were used. Vines of plants grafted on Cucurita rootstocks were generally longer than those of nongrafted plants, but this effect was most significant only during the vegetative developmental stages. Leaf-water potentials (yleaf) of plants grafted on Cucurbita rootstocks were consistently higher than those of nongrafted plants, especially during the critical fruit-development and maturation phases. Melon plants grafted on PI 1207, PI 12404, and PI 20488 also maintained relatively high yleaf. Grafted plants with high yleaf also had high leaf stomatal conductance and transpiration rates, indicating ample water supply from the root systems. Maintenance of high yleaf by grafted plants indicates that such plants could better tolerate root infection and damage by M. cannonballus without late-season collapse.

Guava fruit extracts were analyzed for antioxidant activity measured in methanol extract (AOAM), antioxidant activity measured in dichloromethane extract (AOAD), ascorbic acid, total phenolics, and total carotenoids contents. The ABTS, DPPH, and FRAP assays were used for determining both AOAM and AOAD, whereas the ORACX was used for determining only AOAM. Averaged AOAM [mM Trolox equivalent (TE)/g fresh mass (FM)] were 31.1, 25.2, 26.1, and 21.3 as detreined by the ABTS, DPPH, FRAP, and ORAC respectively. AOAM determined by all assays were well correlated with ascorbic acid (0.61 £ r £ 0.92) but had negative correlation with total carotenoids (-0.67 £ r £ -0.81).

This study evaluated the hypothesis that untreated and irradiated grapefruit as well as the isolated citrus compounds naringin and limonin would protect against azoxymethane (AOM)-induced aberrant crypt foci (ACF) by suppressing proliferation and elevating apoptosis through anti-inflammatory activities. Male Sprague–Dawley rats (n = 100) were provided one of five diets: control (without added grapefruit components), untreated or irradiated (300 Gy, 137Cs) grapefruit pulp powder (13.7 g/kg), naringin (200 mg/kg) or limonin (200 mg/kg). Rats were injected with saline or AOM (15 mg/kg) during the third and fourth week and colons were resected (6 weeks post second injection) for evaluation of ACF, proliferation, apoptosis, and cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) protein levels. Experimental diets had no effect on the variables measured in saline-injected rats. However, in AOM-injected rats, the experimental diets suppressed (P 0.02) aberrant crypt and high multiplicity ACF (HMACF; P 0.01) formation and the proliferative index (P 0.02) compared with the control diet. Only untreated grapefruit and limonin suppressed (P 0.04) HMACF/cm and expansion (P 0.008) of the proliferative zone that occurred in the AOM-injected rats consuming the control diet. All diets elevated (P 0.05) the apoptotic index in AOM-injected rats, compared with the control diet; however, the greatest enhancement was seen with untreated grapefruit and limonin. Untreated grapefruit and limonin diets suppressed elevation of both iNOS (P 0.003) and COX-2 (P 0.032) levels observed in AOM-injected rats consuming the control diet. Although irradiated grapefruit and naringin suppressed iNOS levels in AOM-injected rats, no effect was observed with respect to COX-2 levels. Thus, lower levels of iNOS and COX-2 are associated with suppression of proliferation and upregulation of apoptosis, which may have contributed to a decrease in the number of HMACF in rats provided with untreated grapefruit and limonin. These results suggest that consumption of grapefruit or limonin may help to suppress colon cancer development.

Citrus flavonoids have been shown to possess biological activities such as anti-inflammatory properties, cholesterol lowering and immune system modulation. In this study, 12 made-from-concentrate (MFC) and 14 not-from-concentrate (NFC) orange juices, and five NFC grapefruit juices available in the US market were analyzed for their flavonoid content by reverse phase HPLC. Individual and total flavonoid content was determined for all of the brands. The correlation between flavonoid content (mg) and price (US dollar) per unit volume of orange and grapefruit juices were also evaluated. Significant differences (P0.05) among the brands and within the brand were observed for all of the prominent flavanone glucosides. Within the brand, juice types containing added antioxidant vitamins C and E were not superior in flavonoid content compared to orange juice types devoid of added antioxidant vitamins. Total flavonoid content of MFC orange juices (53 mg/100 mL; n=12) was significantly (P0.05) higher than NFC orange juices (36.5 mg/100 mL; n=14). Hesperidin was found to be the major flavonoid followed by narirutin and didymin in orange juice. Naringin, narirutin, and poncirin were the major flavonoids in all brands of grapefruit juices. The concentration of didymin was considerably higher in NFC orange juices compared to MFC orange juices. Interestingly, no correlation was observed between price and the total flavonoid content of MFC orange juices and NFC grapefruit juices. However, a significant negative correlation (r=-0.49; P=0.001) was observed for NFC orange juices. This study provides valuable information on flavonoid composition of orange and grapefruit juices commonly available in the US market.

Fruits contain a range of phenolics and carotenoids which have been implicated in improving human health. The objective of this study was to characterize the phytochemicals and antioxidant activity (AOA) exhibited in peaches and plums and to determine if any associations existed between these phytochemicals and AOA. Twenty-two peach varieties and fifty-three plum varieties with different flesh and skin color were analyzed for their antioxidant content and AOA. Total phenolics, anthocyanins, and carotenoids were analyzed spectrophotometrically. AOA was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH). Carotenoid content was higher in yellow-flesh (2-3 mg β-carotene/100 g fw-fresh weight) than in white or red-flesh peaches (0.01-1.8 mg β-carotene/100 g fw). AOA was about 2-fold higher in red-flesh varieties than in white/yellow-flesh peach varieties. Among the peaches, the AOA was best correlated with phenolic content. Among the plums, the anthocyanin content increased with the red color intensity. Although the plums varied widely in phenolic content, the red/purple-flesh plums generally had higher phenolic content (400-500 mg chlorogenic acid/100 g fw) than the other plums. Carotenoid content in plums was similar for all varieties. AOA tended to be higher in red/purple-flesh varieties as compared to light colored flesh plums. As with the peaches, the best correlations were between the AOA and the total phenolics content of the fruit

This study was conducted to determine the effects of genetic and environmental factors on onion pungency, estimated as pyruvic acid levels. Genetically identical clones were grown at three different field locations and in a greenhouse. Onion pungency was significantly influenced by clone type, location, and their interaction. Genetic differences were the major determining factor of onion pungency (81.3% of total variation). Location, including all environmental factors, and the clone × location interaction comprised 11.4% and 7.3% of the total variation, respectively. The magnitude of the pungency difference among field-grown onions was about 1.5 μmol/ml. The pungency levels were not positively correlated with soil sulfur nutrition levels, which ranged from 16 to 97 ppm. Within clones, onion pungency levels were loosely inversely correlated with increasing bulb weight. The clones proved to have the most uniform pungency (8% CV), followed by hybrids (10.6% CV) and open-pollinated cultivars (21.3% CV). We have demonstrated that genetic factors were determinant of onion pungency. Environmental factors influenced pungency to a lesser degree. Therefore, choosing cultivars with low pungency, ideal growing environments and proper sulfur nutrition control, are key factor in producing sweet onions.

Limonoid glucosides (primarily limonin 17--D-glucopyranoside, LG) were extracted from grapefruit molasses by supercritical fluid extraction using a supercritical carbon dioxide-ethanol (SC CO2-ethanol) system. Extraction conditions to maximize the yield of LG were determined by varying pressure, temperature, ethanol concentration, and extraction time. The highest yield of LG at 0.61 mg/g molasses was obtained at a pressure 48.3 MPa, a temperature of 50 C, 10% ethanol (XEth = 0.1), and 40 min of extraction time at a flow rate of 5.0 L/min. The results demonstrated that SC CO2 extraction of limonoid glucosides from grapefruit molasses has practical significance for commercial production.

To determine the mechanisms by which dietary fish oil (FO) affects antigen-stimulated Th1 cell development, DO11.10 Rag 2–/– T cell receptor transgenic mice were fed a control diet (5% corn oil (CO) or a FO diet (1% CO + 4% FO, (n-3) PUFA) for 2 wk. CD4+ T cells were cultured under neutral or Th1 polarizing conditions. FO feeding suppressed (P < 0.05) ovalbumin peptide–induced proliferation of nonpolarized CD4+ T cells. Differentiation in vitro to Th1 cells was not affected by dietary FO, as evidenced by similar percentages of KJ1–26+, IFN-+, IL-4– Th1 cells in cultures from CO-fed (99%) and FO-fed (97%) mice. However, the absolute number of viable Th1 cells in polarized cultures from FO-fed mice was less than half that observed in CO-fed mice (P < 0.05), indicating that FO inhibits in vitro Th1 clonal expansion. The reduced number of Th1 cells in FO cultures was not a result of increased apoptosis, because similar percentages of apoptotic Th1 cells were observed in cultures from FO- and CO-fed mice. IL-2–induced cell proliferation was significantly decreased in polarized Th1 cells from the FO group; however, the suppressed proliferation was not linked to reduced CD25 surface expression on antigen-stimulated CD4+ T cells. Adoptively transferred CFSE-labeled DO11.10 CD4+ cells into immunized mice (Th1 polarizing agents) showed that dietary FO reduced (P < 0.05) the number of cell divisions in vivo. These studies suggest that the attenuated inflammatory response which accompanies FO feeding may be explained, at least in part, by suppression of Th1 clonal expansion.