Soon-Teck Jung

Comparative content of some bioactive compounds in apples, peaches and pears and their influence on lipids and antioxidant capacity in rats

The aim of this study was to compare some bioactive compounds in apples, peaches and pears and their influence on lipids and antioxidant capacity in rats. The content of total polyphenols (g/100g) was 0.23 +/- 0.03; 0.22 +/- 0.03 and 0.68 +/- 0.1 in peeled fruits and 0.48 +/- 0.04, 0.47 +/- 0.04 and 1.2 +/- 0.12 in peels of peaches, pears and apples, respectively. Caffeic, p-coumaric and ferulic acids and the total radical-trapping antioxidative potential (TRAP) values in peeled apples and their peels were significantly higher than in peaches and pears, respectively. Contrarary, no significant differences in the content of dietary fiber among the studied fruits were found. The content of all studied indices in peels was significantly higher than peeled fruits (p < 0.05 ). A good correlation between the total polyphenols and the TRAP values was found in all fruits. Diets supplemented with apples and to a less extent with peaches and pears have improved lipid metabolism and increased the plasma antioxidant potential especially in rats fed with added cholesterol. The highest content of biologically active compounds and the best results in the experiment on rats makes apple preferable for dietary prevention of atherosclerosis and other diseases.

Comparison of the contents of the main biochemical compounds and the antioxidant activity of some Spanish olive oils as determined by four different radical scavenging tests.

The aim of this study was to compare the contents of the main biochemical compounds and the antioxidant capacity of five Spanish olive oils by four different antioxidant tests and to find out the most valuable oil for disease preventing diets. Fatty acids, sterols and individual antioxidant compounds in Arbequina, Hojiblanca, Extra Virgin, Picual and Lampante Spanish olive oils were determined. Antioxidant activities were done as well using different radical scavenging activities: total radical-trapping antioxidative potential by ABAP (TRAP-ABAP), radical scavenging activity by DPPH (RSA-DPPH), antioxidant assay by beta-carotene-linoleate model system (AA-beta-carotene) and total antioxidant status by ABTS (TAA-ABTS). The highest content of all studied antioxidant compounds (353; 329; 4.6 and 2.7 mg/kg for tocopherols, tocotrienols, polyphenols and o-diphenols, respectively) was found in Extra Virgin oil. Also the highest antioxidant capacity was observed in Extra Virgin oil (668 nM/ml; 29.4%; 40.4% and 2.64 mM TE/kg for TRAP-ABAP, RSA-DPPH, AA- beta-carotene and TAA-ABTS, respectively). The correlation between total phenols and antioxidant capacities measured by four methods was very high, but the highest for the beta-carotene (R = 0.9958). In conclusion, the best method for determination of the antioxidant capacity of olive oils is the beta-carotene test. Extra Virgin olive oil has high organoleptic properties and the highest antioxidant activity. The above-mentioned makes this oil a preferable choice for diseases preventing diets.

Characterization of antioxidant compounds in Jaffa sweeties and white grapefruits

Antioxidant compounds and the antioxidative activities of new Israeli citrus fruit sweetie [(Oroblanco, pummelo-grapefruit hybrid (Citrus grandis×C. paradisi)] were compared with the better-known white grapefruit. Total and free phenols were determined with the Folin–Ciocalteu reagent, phenolic acids (free, esters and glycosides) by HPLC analysis and anthocyanins spectrophotometrically. The antioxidant activities were estimated with two scavenging radicals: 2, 2′-azinobis (3-ethylbenzothiazoline-6-sulfonate)- (ABTS) and nitric oxide (NO). Free radical scavenging properties of sweetie and grapefruit were evaluated by β-carotene bleaching (β-carotene). The results of kinetic reactions showed that both fruits differed in their capacities to quench these radicals and sweetie showed more antioxidative activity than grapefruit. Trans-hydroxycinnamic acids (caffeic, p-coumaric, ferulic, and sinapic) were more abundant in grapefruits than in sweeties. High correlation was observed between antioxidative activities and phenols (R2=0.94). Both fruits have high concentrations of natural antioxidants with high antioxidative activities. Phenol content and the antioxidative potential are significantly higher in sweetie than in grapefruit. The higher antioxidant capacity of sweetie could make these new kinds of citrus fruits preferable for diets. In summary, the studied citrus fruit has high total phenolics and high antioxidant activities in vitro. Consumption of this fruit may contribute to an adequate intake of antioxidant phytochemicals.

In vitro studies of polyphenols, antioxidants and other dietary indices in kiwifruit (Actinidia deliciosa)

The main aim of the present study was the evaluation of proteins and antioxidant potential in ethylene-treated kiwifruit during the first 10 days of ripening. Kiwifruit samples were randomly divided into two groups: treated and untreated. Flesh firmness, sensory value, visual score, free sugars, soluble solids, ethylene biosynthesis, proteins, dietary fibers, total polyphenols and antioxidant potential were determined in both groups. Ethylene (100 ppm) at 20°C for 24 h was used in the treated group. The flesh firmness and acidity in treated samples decreased significantly in the early stage of ripening simultaneously with significant increase in the contents of free sugars, soluble solids, endogenous ethylene production, sensory value, 1-aminocyclopropane-1-carboxylic acid (ACC) content, ACC synthase and ACC oxidase activities, total polyphenols and related antioxidant potential, and was significantly higher than in untreated samples (P < 0.05). Proteins were extracted from kiwifruit and separated by modified sodium dodecyl sulphate polyacrylamide gel electrophoresis. The separation was resolved into 14 protein bands. Some minor quality changes were found only in the 32 kDa band, which was more pronounced in the treated samples. In conclusion, ethylene treatment of kiwifruits leads to positive changes in most of the studied kiwifruit compounds and to an increase in the fruit antioxidant potential. It shortens the ripening time and improves fruit quality by decreasing its flesh firmness and acidity. Some minor changes in the protein profile did not affect the fruit taste and quality.

Some essential phytochemicals and the antioxidant potential in fresh and dried persimmon

Fresh persimmon contains high quantities of bioactive compounds, but is only available in the autumn and winter months. The aim of this investigation was to compare fresh and dried persimmon in order to determine whether the latter could be a substitute for fresh fruit. It was found that the contents of dietary fibers and trace elements in fresh and equivalent quantities of dried fruits were comparable. The content of total polyphenols in fresh persimmon was higher than in dried fruit, but not significantly (P>0.05). Also the antioxidant potential in fresh persimmon as determined by all three used tests was higher than in dried fruit, but not significantly (P>0.05). The methanol extracts of fresh and dried persimmon using the β-carotene–linoleate model system have shown 91% and 88% of antioxidant activity at 50 µl, respectively. Radical scavenging activity with the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method has shown 88% and 84% for the same extracts and the nitric oxide test showed similar results. The best correlation was found between polyphenols, β-carotene, DPPH and nitric oxide values (R2 ranges between 0.9535 and 0.9934). In conclusion, both fresh and dried persimmon possess high contents of bioactive compounds and have a high antioxidant potential. When fresh fruits are not available, proper dried persimmon can be successfully used.

Screening of the antioxidant and nutritional properties, phenolic contents and proteins of five durian cultivars

The antioxidant activities of different durian cultivars at the same stage of ripening (Mon Thong, Chani, Kan Yao, Pung Manee and Kradum) were compared in order to choose the best as a supplement in the human diet. Total polyphenols (mg gallic acid equivalent/100 g fresh weight (FW)) and flavonoids (mg catechin equivalent (CE)/100 g FW) in Mon Thong (361.4±23.2 and 93.9±7.4) were significantly higher (P<0.05) than in Kradum (271.5±11.2 and 69.2±5.3) and Kan Yao (283.2±16.5 and 72.1±6.8). The free polyphenols and flavonoids showed lower results than the hydrolyzed ones. Anthocyanins (µg cyanidin-3-glucoside equivalent/100 g FW) and flavanols (µg CE/100 g FW) were significantly higher in Mon Thong (427.3±23.8 and 171.4±16.3) than in Kradum (320.2±12.1 and 128.6±9.7) and Kan Yao (335.3±14.1 and 134.4±11.7). Ultraviolet spectroscopy and high-performance liquid chromatography/diode array detection analyses showed that caffeic acid and quercetin were the dominant bioactive substances in Mon Thong cultivar. The antioxidant activity (µM trolox equivalent/100 g FW) of Mon Thong cultivar (260.8±20.2, 1,075.6±81.4 and 2,352.7±124.2) determined by ferric-reducing/antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) with Trolox equivalent antioxidant capacity (TEAC) assays was significantly higher (P<0.05) than in Kradum (197.4±8.9, 806.5±31.2 and 1,773.2±102.5) and in Kan Yao (204.7±9.7, 845.5±48.6 and 1,843.6±107.5). The correlation coefficients between polyphenols, flavonoids, flavanols and FRAP, CUPRAC and TEAC capacities were between 0.89 and 0.98. In extracted and separated by electrophoresis durian proteins, some differences were found in the sodium dodecyl sulfate–protein bands in the region of 16 and 68 kDa for Kradum, 45 kDa for Mon Thong and three bands for Kan Yao. Antioxidants and proteins can be used for characterization of the quality of durian cultivars. In conclusion, the bioactivity of durian cultivars Mon Thong, Chani and Pung Manee was high and the total polyphenols were the main contributors to the overall antioxidant capacity. The results of our investigation in vitro are comparable with other fruits that widely used in human diets. Therefore, Durian can be used as a supplement for nutritional and healthy purposes, especially Durian Mon Thong, Chani and Pung Manee.

Bioactive Compounds and Antioxidant and Antiproliferative Activities of Korean White Lotus Cultivars

In traditional Korean medicine, lotus (Nelumbo nucifera Gaertn) roots have been used as an antidiabetic and an antiproliferative remedy. However, scientific publications on lotus properties are very limited. Therefore, it was decided to investigate the Korean white lotus cultivars in order to find out their bioactivity. It was found that all lotus cultivars (Inchisa, Muan, Garam, and Chungyang) possess high amounts of bioactive compounds: total phenols, between 7.95 +/- 0.8 and 4.21 +/- 0.3 mg of gallic acid equivalents (GAE)/g dry weight (DW); ascorbic acid, between 15.8 +/- 1.1 and 22.3 +/- 1.7 mg of ascorbic acid/g DW; and amino acids, between 15.05 +/- 0.82% and 16.62 +/- 0.90% DW. The highest contents of polyphenols (7.95 +/- 0.8 mg of GAE/g DW) and the highest levels of antioxidant [by 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and 1,1-diphenyl-2-picrylhydrazyl assays, 54.27 +/- 6.1 and 21.98 +/- 2.5 microM Trolox equivalents/g DW, respectively] and antiproliferative activities on both human cancer cell lines (Calu-6 for human pulmonary carcinoma and SMU-601 for human gastric carcinoma, 59.75 +/- 3.99% and 71.21 +/- 2.79% cell viability, respectively) were found in the Chungyang cultivar. Fluorometry and Fourier transform infrared spectroscopy can be applied as rapid methods for determination of bioactive compounds, such as polyphenols. The correlation between the bioactive compounds and the antioxidant activity was high. In conclusion, all Korean white lotus cultivars are valuable medicinal foods, and in order to receive the best results a combination of lotus cultivars has to be consumed.

Rapana venosa as a bioindicator of environmental pollution

The aim of this investigation was to examine biochemical differences in the gastropod Rapana venosa (R. venosa) from polluted (RvP) and nonpolluted (RvN) sites of the Black Seas Bulgarian coast that may serve as bioindicators of environmental quality. Mussels Mytilus galloprovincialis (MMg) were collected from polluted (MMgP) and nonpolluted (MMgN) sites at the same time for comparison. Bioactive compounds and the antioxidant activity of dry matter (DM) methanol extracts from RvP and RvN were determined. Three-dimensional fluorometry (3D-FL) and Fourier transform infrared (FTIR) analyses were used to evaluate polyphenols and proteins. DM methanol extracts from RvP, and to lesser extent RvN, showed high amounts of total phenolics (23.22±2.9 and 15.60±1.8 mg GAE · g−1 DW) and exhibited high levels of antioxidant activity in some radical scavenging assays (μ MTE · g−1 DW): 56.38±5.2 and 33.79±3.3 by 2,2azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) diamonium salt (ABTS·+); 54.79±5.6 and 33.7±2.6 by cupric reducing antioxidant capacity (CUPRAC); 62.34±6.8 and 30.31±3.9 by the 1diphenyl-2-picrylhydrazyl method (DPPH). A correlation in the above indices was found between R. venosa and M. galloprovincialis, but all results were relatively higher for M. galloprovincialis than for R. venosa. The obtained indices of R. venosa may serve as a bioindicator of environmental ecological quality.