Rui Hai Liu

Cornell University, Ithaca, New York, United States

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Publications (76)225.75 Total impact

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    ABSTRACT: Consumption of plant foods has been negatively associated with risk of developing chronic diseases, which is partly attributed to their rich and diverse phytochemicals. In order to promote the rational and effective application of Adinandra tea (Adinandra Jack), a traditional Chinese tea (Shiyacha) widely consumed as a health beverage, the complete phytochemical profiles and antioxidant activities of four varieties of Adinandra tea were analyzed. They were rich in phenolics and flavonoids, ranging from 71.29 to 140.54 mg gallic acid equivalents /g, and from 19.13 to 88.72 mg catechin equivalents /g respectively. Their antioxidant capacities were high as revealed by ORAC, PSC and CAA assay. Obvious antiproliferation effect was observed in HepG2 and MCF-7 cells, with EC50 ranging from 1.05 to 6.44 mg/mL, and from 2.26 to 8.02 mg/mL respectively. Among the four varieties compared, Nitida and Millettii had higher CAA value and anti-proliferation activity, while Latifolia contained considerable bound phenolics.
    Journal of agricultural and food chemistry. 12/2014;
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    ABSTRACT: This paper reports the antioxidant activity of a tropical fruit juice and its antiproliferative and antimutagenic effects. The antioxidant activity was determined by several different methods, such as ORAC, ABTS, PSC (peroxyl radical scavenging capacity) and CAA (cellular antioxidant activity). The total of phenolics and flavonoids were determined, and the phenolic compounds were identified by LC-DAD-ESI-MS. The juice showed high total phenolic and flavonoid contents (838.44 ± 30.27 g GAE/100 g and 219.45 ± 12.27 mg CE/100 g DW, respectively). According to the PSC, CAA, ABTS and ORAC assays, the tropical fruit juice showed a high antioxidant value of 308.39 ± 3.10 μM AEE/100 g, 26.76 ± 4.47 μM QE/100 g, 167.17 ± 4.10 μM TE/g DW and 235.90 ± 11.90 μM TE/g DW, respectively. The proliferation of HepG2 was significantly inhibited, in a dose-dependent manner, by exposure to the tropical fruit juice. Antimutagenic activity was investigated by micronucleous test in mice, and all doses evaluated (30, 100 and 300 mg/kg b.w.) showed beneficial effects. As a consequence, these results encourage further studies on the pharmacological and functional properties of this tropical fruit juice, in order to evaluate its use as a functional food, due to its beneficial health properties.
    Lebensmittel-Wissenschaft und-Technologie 12/2014; 59(2):1319–1324. · 2.55 Impact Factor
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    ABSTRACT: Grapes are rich in phytochemicals with many proven health benefits. Phenolic profiles, antioxidant and antiproliferative activities of twenty-four selected Vitis vinifera grape cultivars were investigated in this study. Large ranges of variation were found in these cultivars for the contents of total phenolics (95.3 to 686.5 mg/100 g) and flavonoids (94.7 to 1055 mg/100 g) and antioxidant activities (oxygen radical absorbance capacity 378.7 to 3386.0 mg of Trolox equivalents/100 g and peroxylradical scavenging capacity14.2 to 557 mg of vitamin C equivalents/100 g), cellular antioxidant activities (3.9 to 139.9 µmol of quercetin equivalents/100 g without PBS wash and 1.4 to 95.8 µmol of quercetin equivalents /100 g with PBS wash) and antiproliferative activities (25 to 82% at the concentrations of 100 mg/mL extracts).The total antioxidant activities were significantly correlated with the total phenolics and flavonoids. However, no significant correlations were found between antiproliferative activities and total phenolics or total flavonoids content. Wine grapes and color grapes showed much higher levels of phytochemicals and antioxidant activities than table grapes and green/yellow grapes. Several germplasm accessions with much high contents of phenolics and flavonoids, and total antioxidant activity were identified. These germplasm can be valuable sources of genes for breeding grape cultivars with better nutritional qualities of wine and table grapes in the future.
    PLoS ONE 01/2014; 9(8):e105146. · 3.53 Impact Factor
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    ABSTRACT: Increased consumption of vegetables or plant food has been associated with decreased risk of developing major chronic diseases, such as cancers, diabetes, cardiovascular diseases, and age-related functional decline. Ramie leaves are rich in phenolics and flavonoids, which have been suggested for human health benefits. Phenolic contents, flavonoid contents, phenolic compounds, and anti-cancer properties in six species of ramie leaves were analyzed by Folin-reagent method, sodium borohydride/chloranil-based assay (SBC), HPLC method and antiproliferation, cytoxicity, respectively. Antioxidant activities were measured through peroxyl radical scavenging capacity (PSC) method, oxygen radical absorbance capacity (ORAC) method, and cellular antioxidant activity (CAA). Research indicated that Boehmeria penduliflora contained the highest total phenolic content (2313.7±27.28 mg GAE/100 g FW), and flavonoid content (1682.4±27.70 mg CAE/100 g FW). Boehmeria tricuspis showed the highest PSC value (9574.8±117.63 µM vit. C equiv./100 g FW), while Boehmeria penduliflora indicated the highest ORAC value (330.44±16.88 µmol Trolox equiv./g FW). The antioxidant activities were correlated with phenolic contents and flavonoid contents. Boehmeria tricuspis had the highest antiproliferative capacity with the lowest EC50 (4.11±0.19 mg/mL). The results for the analyzed ramie for CAA were significantly different from each other (p<0.05), Boehmeria tricuspis had the highest CAA value (133.63±7.10 µmol QE/100 g). Benzoic acid, 4-coumaric acid, caffeic acid, and ferulic acid were the dominant phenolic ingredients in the ramie leaves according to HPLC analysis. Our research is the first report to study the phytochemical profiles and antioxidant activities in different species of ramie leaves for their health benefit.
    PLoS ONE 01/2014; 9(9):e108140. · 3.53 Impact Factor
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    ABSTRACT: ABSTRACT Understanding the influence of processing operations such as drying/dehydration, canning, extrusion, high hydrostatic pressure, pulsed electric field and ohmic heating on the phytochemicals of fruits, vegetables and grains is important in retaining the health benefiting properties of these antioxidative compounds in processed food products. Most of the previous investigations in the literature on the antioxidants of fruits, vegetables, and grains have shown that food processing operations reduced the antioxidants of the processed foods, which is also the usual consumer perception. However, in the last decade some articles in the literature reported that the evaluation of nutritional quality of processd fruits and vegetables not only depend on the quantity of vitamin C but should include analyses of other antioxidant phytochemicals and antioxidant activity. Thermal processing increased the total antioxidant activity of tomato and sweet corn. Most importantly, analysis also depends on the condition, type, and mechanism of antioxidant assays used. This review aims to provide concise information on the influence of various thermal and non-thermal food processing operations on the stability and kinetics of health beneficial phenolic antioxidants of fruits, vegetables and grains.
    Critical reviews in food science and nutrition. 08/2013;
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    ABSTRACT: Phenolics including flavonoids are suggested to be the major bioactive compounds contributing to the health benefits of fruits and vegetables. The objective of the study was to determine the total phenolic and flavonoid contents, oxygen radical absorbance capacity (ORAC), peroxyl radical scavenging capacity (PSC), cellular antioxidant activity (CAA) and antiproliferative properties of selected cerrado fruits named gabiroba (Campomanesia cambessedeana Berg), murici (Byrsonoma verbascifolia Rich) and guapeva (Pouteria guardneriana Radlk). Gabiroba fruit showed the highest amount of total phenolics (851.0 ± 40.7 mg/100 g fruit) and the highest antioxidant activity for both the performed assays (ORAC 8027.5 ± 378.6 μmol TE/100 g fruit and PSC 2342.5 ± 48.1 μmol AAE/100 g fruit). Gabiroba fruit and the pulp of guapeva had the highest antiproliferative capacity with the lowest EC50 40.7 ± 4.8 mg/mL and 37.9 ± 2.2 mg/mL, respectively. The results for the analyzed fruits for CAA were not significantly different from each other (p < 0.05) (murici 41.3 ± 17.8; gabiroba 33.9 ± 18.8 and the pulp of guapeva 23.3 ± 4.2 μmol quercetin/100 g fruit). More than 30 phenolic compounds in the pulp of guapeva, gabiroba and murici extracts were identified in the present study using ESI–TOF-MS. These results characterized for the first time the functional activity of selected Brazilian fruits and demonstrated the importance of these fruits from cerrado biome.
    Food Research International. 08/2013; 53(1):417–425.
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    ABSTRACT: Consumption of whole grains has been associated with reduced risk of developing major chronic diseases. These health benefits have been attributed in part to their unique phytochemicals. Little is known about the complete profiles of phytochemicals and antioxidant activities of different adlay varieties. The objectives of this study were to determine the phytochemicals profiles of the three adlay varieties, including both free and bound of total phenolics and total flavonoids, and to determine the total antioxidant activity of adlay. The free, bound, and total phenolic contents of adlay samples ranged from 31.23 to 45.19 , from 28.07 to 30.86 , and from 59.30 to 76.04 mg of gallic acid equivalents/100 g of sample, respectively. On average, the bound phenolics contributed 45.3% of total phenolic content of the adlay varieties analyzed. The free, bound, and total flavonoid contents of adlay samples ranged from 6.21 to 18.24 , from 18.68 to 35.27 , and from 24.88 to 52.86 mg of catechin equivalents/100 g, respectively. The average values of bound flavonoids contributed 71.1% of total flavonoids of the adlay varieties analyzed. The percentage contribution of flavonoid content to phenolic content of free, bound and total ranged from 11.6 to 35.2 %, from 50.5 to 66.8 %, and from 24.6 to 50.5 %. The free, bound, and total oxygen radical absorbance capacity (ORAC) values of adlay samples ranged from 231.9 to 316.6 , from 209.0 to 351.4 , and from 440.9 to 668.0 mg of Trolox equivalents/100 g , respectively. The average ORAC values of bound phytochemicals contributed 48.1 % of total antioxidant activity of the adlay varieties analyzed. The content of totel polyphenol and the antioxidant capacity are obviously different among different species. Liaoning 5 adlay and Longyi 1 adlay are significantly better than Guizhou heigu adlay. The adlay extracts has obvious proliferate inhibition on human liver cancer cells, and substantially in the experimental concentration range, the adlay sample itself has no cytotoxicity. Knowing the phytochemical profiles and antioxidant activity of adlay gives insights to its potential application to promote health.
    Journal of Agricultural and Food Chemistry 05/2013; · 3.11 Impact Factor
  • Rui Hai Liu
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    ABSTRACT: Regular consumption of fruits, vegetables, whole grains, and other plant foods has been negatively correlated with the risk of the development of chronic diseases. There is a huge gap between the average consumption of fruits and vegetables in Americans and the amount recommended by the 2010 Dietary Guidelines for Americans. The key is to encourage consumers to increase the total amount to 9 to 13 servings of fruits and vegetables in all forms available. Fresh, processed fruits and vegetables including frozen and canned, cooked, 100% fruit juices and 100% vegetable juices, as well as dry fruits are all considered as servings of fruits and vegetables per day. A wide variety of fruits, vegetables, whole grains, and other plant foods provide a range of nutrients and different bioactive compounds including phytochemicals, vitamins, minerals, and fibers. Potatoes serve as one of the low-fat foods with unique nutrients and phytochemical profiles, particularly rich in vitamin C, vitamin B-6, potassium, manganese, and dietary fibers. Potatoes provide 25% of vegetable phenolics in the American diet, the largest contributors among the 27 vegetables commonly consumed in the United States, including flavonoids (quercetin and kaempferol), phenolic acids (chlorogenic acid and caffeic acid), and carotenoids (lutein and zeaxanthin). More and more evidence suggests that the health benefits of fruits, vegetables, whole grains, and other plant foods are attributed to the synergy or interactions of bioactive compounds and other nutrients in whole foods. Therefore, consumers should obtain their nutrients, antioxidants, bioactive compounds, and phytochemicals from a balanced diet with a wide variety of fruits, vegetables, whole grains, and other plant foods for optimal nutrition, health, and well-being, not from dietary supplements.
    Advances in Nutrition 01/2013; 4(3):384S-392S. · 3.20 Impact Factor
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    Rahul Venugopal, Rui Hai Liu
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    ABSTRACT: Breast cancer is the second leading cause of death from cancer in women in the United States. A growing emphasis is being placed on alternative medicine and dietary approaches toward prevention of potential diseases. Phytochemicals are bioactive compounds that are naturally present in foods that, when acting in synergy, bestow potential anti-cancer properties. Resveratrol, a phytoalexin, and ursolic acid, a pentacyclic triterpenoid, are two bioactive compounds that are at the forefront in scientific research. Previous animal studies have documented the anti-cancer properties of resveratrol on breast cancer cells and research groups have recently been able to identify the anti-cancer, anti-inflammatory and induction of apoptosis properties of resveratrol along with the signal transduction pathways that the compound affects. Ursolic acid has been cast into the limelight with the recent discovery documenting its anti-inflammation and anti-cancer activities by targeting signal pathways, especially in the prevention of breast cancer.
    Food Science and Human Wellness. 12/2012; 1(1):1–13.
  • Xinbo Guo, Tong Li, Kexuan Tang, Rui Hai Liu
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    ABSTRACT: Epidemiological studies have shown that regular consumption of fruits and vegetables is associated with reduced risk of chronic diseases. It is recommended to increase consumption of fruits and vegetables to prevent chronic diseases related to free radical-induced oxidative stress. Different varieties of fruits and vegetables provide different vitamins, phenolics, flavonoids, minerals and dietary fibers for optimal health benefits. Mung bean sprouts are one of the major vegetables in human diet. However, the profile of phytochemicals and effect of germination on phytochemical content and antioxidant activity of mung bean sprouts has not been studied. The objective of this study was to determine the effect of germination on phytochemical profiles and antioxidant activity of mung bean sprouts. Germination of mung beans dramatically increased vitamin C contents in mung bean sprout in a time-dependent manner and reached the peak on day 8 of germination up to 285 mg/100 g DW, almost 24 times higher than the initial concentration in mung bean seeds (p<0.05). On fresh weight basis, one serving of mung bean sprouts (about 104 g) provides 21.6 mg of vitamin C, which could meet 36% of Daily Value (DV). In addition, the germination dramatically increased total phenolic compounds and total flavonoids in mung bean sprouts in a time-dependent manner, up to 4.5 and 6.8 times higher than the original concentration of mung bean seeds, respectively. Quercetin-3-O-glucoside content was significantly increased in mung bean sprouts after germination. The total antioxidant activity of mung bean sprouts was increased by 6 times higher than that of mung bean seeds. Therefore, the germination of mung bean sprouts significantly increased phytochemical content, vitamin C content and antioxidant activity.
    Journal of Agricultural and Food Chemistry 10/2012; · 3.11 Impact Factor
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    ABSTRACT: The presence of the foodborne pathogen Listeria monocytogenes on cold-smoked salmon is a major concern for the seafood industry. Understanding processing and postprocessing handling factors that affect the ability of this pathogen to grow on cold-smoked salmon is critical for developing effective control strategies. In this study, we investigated the effect of curing method and freeze-thawing of cold-smoked salmon on (i) physicochemical properties and (ii) subsequent growth of genetically diverse strains of L. monocytogenes (inoculated after freeze-thawing) and endogenous lactic acid bacteria. The majority of the measured physicochemical properties were unaffected by freezing and thawing. Overall, wet-cured cold-smoked salmon had higher pH, water activity, and moisture, as well as lower fat, water-phase salt, and phenolic content compared with dry-cured cold-smoked salmon. The curing method and freeze-thawing did not affect growth of endogenous lactic acid bacteria. Freeze-thawing cold-smoked salmon prior to inoculation led to pronounced growth of L. monocytogenes at 7°C. The increase in cell density between days 0 and 30 was significantly (P = 0.0078) greater for cold-smoked salmon that was frozen and thawed prior to inoculation compared with nonfrozen cold-smoked salmon. On dry-cured, freeze-thawed cold-smoked salmon, L. monocytogenes had a lag phase ranging from 3.7 ± 0.1 to 11.2 ± 1.4 days compared with salmon that was wet cured and freeze-thawed, on which L. monocytogenes began to grow within 24 h. Variation in growth among L. monocytogenes strains was also observed, indicating the significance of assessing multiple strains. Further efforts to understand the impact of processing and postprocessing handling steps of cold-smoked salmon on the growth of genetically diverse L. monocytogenes will contribute to improved challenge study designs and data. This, in turn, will likely lead to more reliable and unbiased risk assessments and control measures.
    Journal of food protection 09/2012; 75(9):1619-26. · 1.83 Impact Factor
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    ABSTRACT: Consumption of plant food rich meals, such as feijoada, a traditional meal in Brazil, is associated with the reduction of chronic disease. The objectives of this study were to determine phytochemical content and antioxidant activity by chemical and cellular antioxidant assays (CAA) of feijoada with or without in vitro digestion. Feijoada showed no difference in phenolics and flavonoids after digestion. Bound and residue contributions to total phenolics were 20.9% and 32.2%, respectively, suggesting that phenolics reach the colon after intake. Flavonoids in residue and bound fractions represented 50% of total flavonoids. Antioxidant activity of feijoada without digestion was higher than that with digestion; however, it showed lower antiproliferative activity and CAA. Feijoada with in vitro digestion also yielded phenolics with higher CAA. Analyses of whole meals should be used to evaluate phytochemicals present in food mixtures consumed, especially with digestion models coupled with CAA resulting in information similar to those in physiological conditions.
    Journal of Agricultural and Food Chemistry 04/2012; 60(19):4826-32. · 3.11 Impact Factor
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    ABSTRACT: Loach protein hydrolysates (LPH) prepared by papain digestion were fractionated into four fractions, LPH-I (MW > 10 kDa), LPH-II (MW = 5-10 kDa), LPH-III (MW = 3-5 kDa), LPH-IV (MW < 3 kDa), and the in vitro antioxidant and antiproliferative (anticancer) activities of all fractions were determined. LPH-IV showed the lowest IC(50) value (16.9 ± 0.21 mg/mL) for hydroxyl radical scavenging activity and the highest oxygen radical scavenging capacity (ORAC) value (reaching 215 ± 5.9 mM Trolox/100 g loach peptide when the concentration was 60 μg/mL). Compared with other fractions, LPH-IV also exhibited stronger antiproliferative activity for human liver (HepG2), breast (MCF-7), and colon (Caco-2) cancer cell lines in a dose-dependent manner. When the protein concentration was 40 mg/mL, the HepG2 and MCF-7 cell proliferation of LPH-IV reached 7 and 4%, respectively, with no significant difference from those of LPH (8 and 7%, p > 0.05), with significantly less growth than those of LPH-I, LPH-II, and LPH-III, respectively (p < 0.05). The Caco-2 colon cell proliferation of LPH-IV was 12.8- and 8.7-fold smaller than those of LPH-I and LPH-II, respectively (p < 0.05). All of the fractions had a greater ability to inhibit Caco-2 colon cancer cell proliferation than to inhibit HepG2 liver cancer and MCF-7 breast cancer cell proliferation. The ORAC values of most of the fractions correlated (R(2) > 0.86, p < 0.01) with the antiproliferative activity of the three cancer cell lines, suggesting that higher antioxidant activity leads to better antiproliferative activity. However, further mechanistic and human clinical studies of the anticancer activity of loach protein hydrolysate fractions are needed.
    Journal of Agricultural and Food Chemistry 06/2011; 59(14):7948-53. · 3.11 Impact Factor
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    ABSTRACT: Measuring antioxidant activity using a biologically relevant assay adds important evidence to aid in understanding the role of phytochemicals based on data from in vivo and chemical assays of extrusion processed purple potato and pea flours. A cellular antioxidant activity assay could provide biologically relevant information on bioactive compounds in raw as well as processed food products. The objective of this study was to investigate the complete phytochemical profiles, antioxidant activity, cellular antioxidant activity, and their contribution to bioactivity in purple potato flour, dry pea flour, raw formulations, and extrusion cooked products prepared with the above ingredients. The free fraction of extracts contributed 68, 64, and 88% to total phenolics, total antioxidant activity (ORAC value), and total flavonoids, respectively, in purple potato flour (PPF). Similarly, extracts in the free fraction contributed 87, 86, and 64% to total phenolics, total antioxidant activity (ORAC value), and total flavonoids, respectively, in dry pea flour (DPF). The amount of total phenolics and total flavonoids in purple potato flour and the antioxidant activity of PPF and DPF were comparable to published data. However, a higher amount in the total flavonoids and lower in the total phenolics of DPF were observed. Caffeic, p-coumaric, and ferulic acids were mostly observed in the bound extracts of raw formulations as in the extrudates, whereas chlorogenic acid was predominant in the free extracts. The extruded products had significantly higher (p < 0.05) content of total phenolics, ORAC antioxidant activity, and flavonoids, compared to the raw formulations. Extrusion processing increased the cellular antioxidant activity of the extrudates prepared from 35:65 and 50:50 PPF/DPF (w/w) of ingredients compared with control raw formulations in a dose-dependent manner. Increase of PPF significantly increased (p < 0.05) the cellular antioxidant activity of 35-50% PPF formulations.
    Journal of Agricultural and Food Chemistry 05/2011; 59(15):8233-43. · 3.11 Impact Factor
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    ABSTRACT: Coffee consumption is correlated with a lower risk for type 2 diabetes mellitus (T2D), though whether differences exist in the T2D-mitigating bioactivities of decaffeinated (RD) and regular (RR) coffee is unclear. We conducted cell-based experiments to determine whether different phenolic levels in RD and RR affect T2D-mitigating bioactivities. The total phenolic content and the chemical antioxidant activity were significantly higher in RD than RR. However, these coffees had comparable cellular antioxidant activity. Both coffees reduced activation of NF-κB, with RR being twice as strong as RD. They also both increased glucose uptake in human adipocytes by 2-fold. Of the bioactivities examined, only chemical antioxidant activity was related to total phenolic levels. The NF-κB inhibition was proportional to chlorogenic acid levels, though chlorogenic acids could not account for the full inhibitory effect of coffee. Thus, a matrix effect may exist, whereby components of coffee work together to provide bioactivities that ameliorate the T2D risk.
    Food Chemistry. 01/2011;
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    ABSTRACT: As green tea is being consumed in larger amounts, more green tea waste is being produced. Following extraction, several bioactive compounds may exist in the waste including polyphenols and amino acids. It was found that an Aspergillus niger cellulase treatment of green tea waste increased the extractability of various nutritional and functional components after pretreatments with various extraction solvents such as cold water (CW), hot water (HW), sulfuric acid (SA), hydrochloric acid (HA), and methanol (Me). After the residue was treated with cellulase from Aspergillus niger, the amounts of polyphenols, total catechins, and reducing sugars in the HW extract were increased by 64.6, 941.2, and 350.9%, respectively. In particular, levels of epigallocatechin, epicatechin, and gallic acid were significantly enhanced compared to those in the nontreated control. However, protein extraction was not significantly affected, and cellulase treatment was not more efficient for caffeine extraction compared to phenolic extraction. Among the four extraction solvents, HW and SA showed relatively higher extractabilities as compared to the other groups (CW, HA, and Me). These results indicate that cellulase from A. niger can increase the extractability of green tea waste when combined with certain solvent pretreatments. Consequently, the residual functional compounds and essential nutrients from cellulase-treated green tea waste have the potential to be applied in the production of new functional foods.
    Journal of Agricultural and Food Chemistry 10/2010; 58(19):10747-51. · 3.11 Impact Factor
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    ABSTRACT: Antrodia cinnamomea is known for its antihepatoma activity, yet the identity of its active compound was unclear. In this study, a 5-ton fermenter was used to prepare sufficient mycelium of A. cinnamomea for active compound isolation and identification. Using antiproliferative activity toward HepG2 cells as guidance in the isolation process, 4-acetylantroquinonol B was purified and identified to be the major bioactive compound of A. cinnamomea cultivated by submerged fermentation. The median effective doses (EC(50)) of 4-acetylantroquinonol B for HepG2 cells were 0.10 +/- 0.00 and 0.08 +/- 0.00 microg mL(-1) for 72 and 96 h treatments, respectively. The selective indices of 4-acetylantroquinonol B were 100 and 125 for 72 and 96 h treatments, respectively, indicating that this compound had high selective activity for hepatoma cells. 4-Acetylantroquinonol B is the major antihepatoma constituent of Antrodia cinnamomea mycelium produced by submerged fermentation.
    Journal of the Science of Food and Agriculture 08/2010; 90(10):1739-44. · 1.88 Impact Factor
  • Lijun You, Joe M Regenstein, Rui Hai Liu
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    ABSTRACT: Fish skin gelatin was hydrolyzed with papain to produce antioxidant peptides. Response surface methodology (RSM) was applied to optimize the hydrolysis conditions (including enzyme to substrate ratio [E/S], hydrolysis time, and temperature). The highest degree of hydrolysis (DH) (50.1 +/- 1.1%) was obtained at an E/S of 2% at 56.8 degrees C, 2.11 h, and was not significantly different from the predicted values within a 95% confidence interval. The highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) (96.8 +/- 0.9%) and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS(*+)) (9.80 +/- 0.11 mM Trolox [6-hydroxy-2,5,7,8-tetramethychroman-2-carboxylic acid]) radical-scavenging activities of fish gelatin hydrolyzates were obtained at an E/S of 3% at 52.1 degrees C, 2.65 h, and both DPPH and ABTS(*+) radical-scavenging activities were not significantly different from the predicted values 97.3% and 9.86 mM Trolox within the 95% confidence interval. Therefore, RSM is an efficient way to optimize fish gelatin hydrolysation and the resultant hydrolyzates show promise as antioxidant peptides. Practical Application: There is a growing interest in the use of fish gelatin as an alternative to mammalian gelatin. One potential use is as a source of widely acceptable functional compounds. In this study, a search for antioxidant peptides from fish gelatin prepared by an enzymatic method has been successfully done. This suggests that this is a practical way to obtain bioactive peptides.
    Journal of Food Science 08/2010; 75(6):C582-7. · 1.78 Impact Factor
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    ABSTRACT: Increased consumption of whole grains has been associated with reduced risk of developing major chronic diseases. These health benefits have been attributed in part to their unique phytochemicals. Previous studies on black rice mainly focused on anthocyanins. Little is known about the phytochemical profiles and antioxidant activities of different black rice varieties. The objective of this study was to determine the phytochemical profiles and antioxidant activity of rice bran samples from 12 diverse varieties of black rice. The free, bound, and total phenolic contents of black rice bran samples ranged from 2086 to 7043, from 221.2 to 382.7, and from 2365 to 7367 mg of gallic acid equiv/100 g of dry weight (DW), respectively. The percentage contribution of free phenolics to the total ranged from 88.2 to 95.6%. The average values of free, bound, and total phenolic contents of black rice bran were 8, 1.5, and 6 times higher than those of white rice bran, respectively (p < 0.05). The free, bound, and total flavonoid contents of black rice bran samples ranged from 3462 to 12061, from 126.7 to 386.9, and from 3596 to 12448 mg of catechin equiv/100 g of DW, respectively. The percentage contribution of free flavonoids to the total ranged from 96.3 to 97.6%. The average values of free, bound, and total flavonoid contents of black rice bran were 7.4, 1.9, and 6.7 times higher than those of white rice bran, respectively (p < 0.05). The free, bound, and total anthocyanin contents of black rice bran samples ranged from 1227 to 5096, from 4.89 to 8.23, and from 1231 to 5101 mg of cyanidin-3-glucoside equiv/100 g of DW, respectively. The percentage contribution of free anthocyanins to the total ranged from 99.5 to 99.9%. Cyanidin-3-glucoside, cyanidin-3-rutinoside, and peonidin-3-glucoside were detected in black rice bran samples and ranged from 736.6 to 2557, from 22.70 to 96.62, and from 100.7 to 534.2 mg/100 g of DW, respectively. The free, bound, and total antioxidant activities of black rice bran samples ranged from 476.9 to 180, from 47.91 to 79.48, and from 537.5 to 1876 mumol of Trolox equiv/g of DW, respectively. The percentage contribution of free antioxidant activity to the total ranged from 88.7 to 96.0%. The average values of free, bound, and total antioxidant activity of black rice bran were more than 8, 1.5, and 6 times higher than those of white rice bran, respectively (p < 0.05). The total antioxidant activity of black rice bran was correlated to the content of total phenolics, total flavonoids, and total anthocyanins and also was significantly correlated to the contents of cyanidin-3-glucoside, cyanidin-3-rutinoside, and peonidin-3-glucoside. These results indicate that there are significant differences in phytochemical content and antioxidant activity among the different black rice varieties. Black rice bran has higher content of phenolics, flavonoids, and anthocyanins and has higher antioxidant activity when compared to white rice bran. Interestingly, the phenolics, flavonoids, and anthocyanins of black rice bran are mainly present in free form. Knowing the phytochemical profile and antioxidant activity of black rice bran gives insights to its potential application to promote health.
    Journal of Agricultural and Food Chemistry 07/2010; 58(13):7580-7. · 3.11 Impact Factor
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    ABSTRACT: The measurement of antioxidant activity using biologically relevant assays is important to screen fruits, vegetables, natural products, and dietary supplements for potential health benefits. The cellular antioxidant activity (CAA) assay quantifies antioxidant activity using a cell culture model and was developed to meet the need for a more biologically representative method than the popular chemistry antioxidant capacity measures. The objective of the study was to determine the CAA, total phenolic contents, and oxygen radical absorbance capacity (ORAC) values of 27 vegetables commonly consumed in the United States. Beets, broccoli, and red pepper had the highest CAA values, whereas cucumber had the lowest. CAA values were significantly correlated to total phenolic content. Potatoes were found to be the largest contributors of vegetable phenolics and CAA to the American diet. Increased fruit and vegetable consumption is an effective strategy to increase antioxidant intake and decrease oxidative stress and may lead to reduced risk of developing chronic diseases, such as cancer and cardiovascular disease.
    Journal of Agricultural and Food Chemistry 06/2010; 58(11):6621-9. · 3.11 Impact Factor

Publication Stats

5k Citations
225.75 Total Impact Points

Institutions

  • 2000–2014
    • Cornell University
      • • Department of Horticulture
      • • Department of Food Science
      Ithaca, New York, United States
  • 2012
    • Federal University of Rio de Janeiro
      Rio de Janeiro, Rio de Janeiro, Brazil