BoKyung Moon

Major Phytochemical Composition of 3 Native Korean Citrus Varieties and Bioactive Activity on V79-4 Cells Induced by Oxidative Stress

Three citrus varieties grown in Korea, namely, Yuza (Citrus junos Sieb ex Tanaka), Kjool (Citrus unshiu Marcow), and Dangyooja (Citrus grandis Osbeck), were evaluated for their dietary fiber, total phenolics, total flavonoids, and total carotenoids as well as individual flavonoids composition. The biochemical characteristics of citrus varieties were examined by the antioxidant capacity (731 to 1221 micromol of Trolox equivalent/g), total phenolic (334 to 411 mg of chlorogenic acid equivalent/100 g), total flavonoid contents (214 to 281 mg of catechin equivalent/100 g), and total carotenoid contents (63 to 84 mg/100 g). Six flavonoids, including naringin, naringenin, hesperidin, hesperetin, neohesperidin, and luteolin, were tentatively identified. Naringin, hesperidin, and neohesperidin were the predominant flavonoids in 3 citrus varieties. Among the citrus varieties studied, Yuza showed higher antioxidant activity, total phenolics, total carotenoids, and lower superoxide radical scavenging assay (SRSA) IC(50) values than other varieties. Furthermore, Korean citrus showed higher protective effect on gap-junction intercellular communication (GJIC) as compared to vitamin C and luteolin.

Optimization by response surface methodology of lutein recovery from paprika leaves using accelerated solvent extraction

In this study, we used response surface methodology (RSM) to optimize the extraction conditions for recovering lutein from paprika leaves using accelerated solvent extraction (ASE). The lutein content was quantitatively analyzed using a UPLC equipped with a BEH C18 column. A central composite design (CCD) was employed for experimental design to obtain the optimized combination of extraction temperature (°C), static time (min), and solvent (EtOH, %). The experimental data obtained from a twenty sample set were fitted to a second-order polynomial equation using multiple regression analysis. The adjusted coefficient of determination (R(2)) for the lutein extraction model was 0.9518, and the probability value (p=0.0000) demonstrated a high significance for the regression model. The optimum extraction conditions for lutein were temperature: 93.26°C, static time: 5 min, and solvent: 79.63% EtOH. Under these conditions, the predicted extraction yield of lutein was 232.60 μg/g.

Comparative flavonoids contents of selected herbs and associations of their radical scavenging activity with antiproliferative actions in V79-4 cells.

To elucidate the health benefit of herbal teas on the cytotoxicity induced by H(2)O(2) in V79-4 cells, herbal extracts and its flavonoids were tested using lactate dehydrogenase release and determining intracellular reactive oxygen species generation and antioxidant activity with superoxide radical scavenging assay. Significant decrease in cell viability was observed on V79-4 cells treated with H(2)O(2) (1 mM), while herbal extracts and its flavonoids including catechin and epigallocatechin gallate prevented the LDH release from H(2)O(2) cytotoxicity. Total catechin contents of green tea (65.6 mg/g of dry matter) were significantly higher than other herbal teas (35.8 to 1.2 mg/g of DM). The relative concentration of the 4 major tea catechins ranked EGCG > EGC > EC > C. Green tea exhibited the lowest IC(50) values (2 g fresh herb/100 mL) of superoxide radical scavenging activity among the tested herbal tea, which indicates powerful antioxidant activity in O(2)(*-) radicals scavenging, followed by black tea, dandelion, hawthorn, rose hip, chamomile.

Antioxidant and Anti-inflammatory Activities of Methanol Extracts of Tremella fuciformis and Its Major Phenolic Acids

Methanol extract subfractions of the edible white jelly mushroom (Tremella fuciformis), were assessed for the following antioxidant properties: ABTS(+) radical scavenging activity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, and inhibitory activity of human low-density lipoprotein (LDL) oxidation. Among the subfractions tested, the chloroform subfraction exhibited the strongest antioxidant activity, with the highest total phenolic content (66.31 μg CAE/mg extract) and flavonoids content (5.12 μg QE/mg extract). The ABTS(+) radical scavenging activity of the chloroform subfraction was 7.89 μmol trolox/mg extract, which was the highest among all subfractions. This subfraction also showed the highest DPPH radical scavenging activity and inhibitory activity of LDL oxidation. In addition, the chloroform subfraction demonstrated anti-inflammatory activity through inhibition of nitric oxide production and inducible nitric oxide synthase expression in RAW 264.7 cells. Major phenolic acids from the mushroom extract were identified as 4-hydroxybenzoic acid (323 mg/kg dry weight of mushroom), gentisic acid (174 mg/kg dry weight of mushroom), and 4-coumaric acid (30 mg/kg dry weight of mushroom).

Lithospermum erythrorhizon suppresses high-fat diet-induced obesity, and acetylshikonin, a main compound of Lithospermum erythrorhizon, inhibits adipocyte differentiation.

Lithospermum erythrorhizon, which has traditionally been used as a vegetable and to make the liquor Jindo Hongju, contains several naphthoquinone pigments, including shikonin. This study aimed to evaluate the antiobesity effects of Lithospermum erythrorhizon ethanol extract (LE) and elucidate the underlying mechanism. C57BL/6J mice were fed a normal or high-fat diet with or without LE supplementation for 8 weeks. LE reduced high-fat diet-induced increases in body weight, white adipose tissue mass, serum triglyceride and total cholesterol levels, and hepatic lipid levels while decreasing lipogenic and adipogenic gene expression. Furthermore, acetylshikonin suppressed adipocyte differentiation in a dose-dependent manner and significantly attenuated adipogenic transcription factor expression in 3T3-L1 cells. These findings suggest that Lithospermum erythrorhizon prevents obesity by inhibiting adipogenesis through downregulation of genes involved in the adipogenesis pathway and may be a useful dietary supplement for the prevention of obesity.

Determination of Lutein from Green Tea and Green Tea By-Products Using Accelerated Solvent Extraction and UPLC

UNLABELLED We aimed to identify the optimum conditions for the extraction of lutein from green tea using accelerated solvent extraction, and achieve improved analytical resolution and sensitivity between lutein and zeaxanthin using an ultra performance liquid chromatography (UPLC) system. The optimized method employed 80% ethanol as the extraction solvent, 160 °C as the temperature, 2 static cycles, and 5 min of static time. In the validation of the UPLC method, recovery was found to be in the range approximately 93.73 to 108.79%, with a correlation coefficient of 0.9974 and a relative standard deviation of <9.29% in inter- and intraday precision analyses. Finally, the lutein contents of green tea and green tea by-products were measured as 32.67 ± 0.70 and 18.18 ± 0.68 mg/100g dw, respectively. Furthermore, we verified that green tea by-products, which are discarded after producing green tea beverages, might be used as a great resource for massive lutein production. PRACTICAL APPLICATION We have demonstrated that the common problem of inadequate resolution between lutein and zeaxanthin during carotenoid analyses can be overcome by optimizing the combined techniques of accelerated solvent extraction and ultra performance liquid chromatography (UPLC). UPLC was highly effective for saving time, solvent, and labor, as well as providing better resolution. The results in this study demonstrated that green tea by-products could be used as new sources for industrial lutein production owing to their massive production during the extraction of green tea beverages.

Combined Application of Antibrowning, Heat Treatment and Modified‐Atmosphere Packaging to Extend the Shelf Life of Fresh‐Cut Lotus Root

This work aimed to determine the effects of different concentrations of antibrowning treatments (that is, distilled water [DW], 1% ascorbic acid [AA], 0.5% chamomile [CM], and 1% AA + 0.5% CM) and heat-treatment (55 °C for 45 s) combined with packaging under 4 different modified-atmosphere gas compositions (that is, air, vacuum, 100% CO2 , 50% CO2 /50% N2 ) on the quality and microbiological characteristics of fresh-cut lotus root. The quality characteristics (that is, color, weight loss, texture, pH, polyphenoloxidase activity, and total phenolic content) of the AA + CM-dipped sample in 100% CO2 packaging were maintained significantly better than those of the other samples (P < 0.05). The microbiological counts observed in the DW-dipped sample during storage were higher than those of the AA, CM, and AA + CM samples, and heat-treatment retarded the microbiological deterioration of fresh-cut lotus root. Therefore, the results revealed that dipping in an antibrowning treatment (AA + CM), and 100% CO2 MAP with heat treatment effectively extend the shelf life of fresh-cut lotus root to 21 d at 5 °C.

Effect of Pleurotus eryngii Mushroom β-Glucan on Quality Characteristics of Common Wheat Pasta.

The objective of this study was to evaluate the effect of β-glucan-rich fractions (BGRFs) from Pleurotus eryngii mushroom powder on the quality, textural properties, and sensory evaluation of common wheat pasta. Pasta was prepared from semolina flour and common wheat flour by replacing common wheat flour at 2%, 4%, and 6% with BGRFs. Semolina flour showed significantly higher viscosities than common wheat flour samples. However, all viscosities, except the breakdown viscosity, were reduced with increasing percentages of BGRFs. Replacement of the common wheat flour with BGRFs resulted in a reddish brown colored pasta with a lower L* value and a higher a* value. The common wheat pastas containing up to 4% BGRFs were not significantly different from semolina pasta with regard to cooking loss. Addition of up to 2% BGRFs had no significant impact on swelling index and water absorption. The addition of BGRFs in common wheat flour had a positive effect on the quality of common wheat pasta and resulted in hardness values similar to those of semolina pasta. In a sensory evaluation, cooked pasta with 2% BGRFs had the highest overall acceptability score. In summary, the results showed that common wheat flour containing 4% BGRFs could be used to produce pasta with an improved quality and texture properties similar to semolina pasta.

Intrinsic polyphenol oxidase-like activity of gold@platinum nanoparticles

Metal nanoparticles (NPs) have received considerable attention in recent years for their unique properties and potential applications in catalysis. However, few studies have employed an integrated approach to investigate the enzyme mimetic activities of metal NPs. The aim of the present study was to evaluate the enzyme mimetic activity of gold@platinum (Au@Pt) NPs. Specifically, the lipoxygenase (LOX), glutathione reductase (GR), glutathione peroxidase (GPx), and polyphenol oxidase (PPO) activities of Au@Pt NPs were examined. The results showed that Au@Pt NPs exhibited PPO mimetic activity over a wider range of pH values and temperatures compared with PPO. Kinetic analysis showed that Au@Pt NPs exhibited higher affinity for certain substrates than the natural enzyme PPO. Furthermore, we also determined the catalytic activity of Au@Pt NPs in the autoxidation of phenol substrates, including pyrogallol, 3,4-dihydroxy-L-phenylalanine, and catechol by electron spin resonance.

Characterization of the antioxidant activity of gold@platinum nanoparticles

Gold@platinum (Au@Pt) nanostructures exhibit desirable catalytic abilities and unique optical properties, which are not seen in single-component metal nanoparticles (NPs). To date, however, there is only limited information available in the literature on the integrated approach to investigate the antioxidant activities of Au@Pt NPs. The aim of the present study, was to evaluate the antioxidant activities of hybrid nanorods, i.e., Au@Pt NPs. Specifically, the free radical scavenging effect, hydroxyl radical scavenging activity, and superoxide dismutase (SOD)-like activity of Au@Pt NPs were examined. Furthermore, the in vitro antioxidant ability of Au@Pt NPs was assessed by measuring the cell viability of V79-4 (Chinese hamster lung fibroblasts), PC-3 (human prostate cancer), and MCF-7 (human breast cancer) cells under oxidative stress induced by hydrogen peroxide (H2O2). The results showed that Au@Pt NPs exhibited high DPPH radical scavenging activity, non-site specific hydroxyl radical scavenging activity, linoleic acid peroxidation inhibitory ability by TBA tests in a low Au@Pt NP concentration range. Furthermore, in vitro experiments revealed that Au@Pt NPs showed cellular protection against oxidative stress induced by H2O2.