• Journal of Applied Biological Chemistry
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• v.43 no.2
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• pp.94-100
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• 2000

An analytical method was developed to determine abamectin and milbemectin residues in apple, pear, and citrus using HPLC with ultraviolet absorption detection. Abamectin and milbemectin were extracted with methanol from apple, pear, and citrus samples. The extract was diluted with saline water and dichloromethane partition was followed to recover the compounds from the aqueous phase. Florisil column chromatography and aminopropyl solid-phase extraction were employed as cleanup methods to remove most of co-extractives from the sample extract. Reverse-phase HPLC using an octadecylsilyl column was successfully applied to separate and quantitate abamectin and milbemectin residues in sample extracts at the wavelength of 245 nm. Recoveries of abamectin and milbemectin from fortified samples ranged 80.4~90.3% and 90.9~96.8%, respectively. Relative standard deviations of the analytical method were less than 10% for both acaricides. Detection limit of the analytical method was 0.003 mg/kg sample for all the analytes. The proposed method was reproducible and sensitive enough to evaluate terminal residues of abamectin and milbemectin in apple, pear, and citrus.

• Korean Journal of Environmental Agriculture
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• v.23 no.4
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• pp.245-250
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• 2004

An analytical method was developed to determine monocrotophos residues in apple, citrus, and soil using high-performance liquid chromatography (HPLC) with ultraviolet absorption detection. Monocrotophos was extracted with acetone from apple, citrus and moist soil samples. The extract was concentrated, added with saline water, and subjected to n-hexane washing to remove nonpolar co-extractives. Dichloromethane partition was then followed to recover monocrotophos from the aqueous phase. Silica gel column chromatography was employed to further purify the extract prior to HPLC determination. Reverse-phase HPLC using an oct-adecylsilyl column was successfully applied to separate and quantitate the monocrotophos residue in sample extracts at the wavelength of 230 nm. Overall recoveries of monocrotophos from fortified samples averaged $95.3{\pm}2.1%$ (n=6), $970{\pm}0.7%$ (n=6), and $92.8{\pm}4.3%$ (n=12) for apple, citrus, and soil, respectively. The proposed method was quite reproducible and sensitive enough to replace the troublesome gas-liquid chromatographic analysis for monocrotophos residues.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.121-130
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• 2017

This study was carried out to investigate a method for producing cultured virus - free ovules for breeding high - quality Citrus cultivars. Ovules from the immature fruits of three citrus cultivars native to Jeju (Dongjeongkyool, Cheongkyool, and Jikak) and two cultivars of Citrus unshiu Marc. (Miyagawa wase and Haryejosaeng) that were thought to be infected with Citrus tristeza virus (CTV) were cultured on MS2 medium (Murashige - Skoog [MS] basal medium containing $500mg{\cdot}L^{-1}$ malt extract, $50g{\cdot}L^{-1}$ sucrose, $1.0 mg{\cdot}L^{-1}$ kinetin, and $8g{\cdot}L^{-1}$ agar). After four weeks of culture, 10, 21, 13, 5, and 7 somatic embryos and 2, 4, 2, 4, and 5 white callus cells (surrounding green somatic embryos) were obtained from Dongjeongkyool, Cheongkyool, Jikak, Miyagawa wase, and Haryejosaeng, respectively. After six weeks of culture, somatic embryos were obtained from cultured cells grown on MT basal medium supplemented with malt extract ($500mg{\cdot}L^{-1}$), lactose ($70g{\cdot}L^{-1}$), and agar ($16g{\cdot}L^{-1}$). Over 60% of the somatic embryos from citrus cultivars native to Jeju developed into normal plants on MS basal medium supplemented with malt extract ($500mg{\cdot}L^{-1}$), sucrose ($50g{\cdot}L^{-1}$), and agar ($8g{\cdot}L^{-1}$) after 10 weeks of culture. Normal plants were regenerated from two Citrus unshiu Marc. cultivars on MT basal medium supplemented with sorbitol (1.0 M), galactose (1.0 M), $GA_3$ ($1.0mg{\cdot}L^{-1}$), and Gelrite ($3g{\cdot}L^{-1}$). The absence of virus in plants generated from cultured ovules was confirmed by RT - PCR and antigen - antibody reactions. Therefore, virus - free Citrus cells can be obtained for breeding high - quality citrus cultivars using the biotechnological technique evaluated in this study.

• Korean Journal of Plant Resources
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• v.26 no.3
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• pp.374-382
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• 2013

The objective of this study was determined to evaluate ${\alpha}$-amylase, ${\alpha}$-glucosidase, pancreatic lipase inhibition in vitro and DPPH radical scavenging activity of the several Korean resources plants. The ${\alpha}$-amylase inhibitory activity of Salicornia herbacea, Erythronium japonicum (flower) and Phragmites communis (root) in water extract showed relatively high 62.8%, 66.5% and 69.3%, respectively. The ${\alpha}$-amylase inhibitory activity of Citrus junos (pericarp) and Cornus officinalis in methanol extract was found to have an effect with 32.8% in Citrus junos (pericarp) and 60.9% in Cornus officinalis. Corylopsis coreana in both water and methanol extract had the highest ${\alpha}$-glucosidase inhibitory activity of 81.7% and 89.5%, while the extract of Portulaca oleracea, Ficus carica and Citrus junos was not measured ${\alpha}$-glucosidase inhibitory activity at given experiment concentration. Depending on the extraction solvent and the plant species, it was observed that there was a significant difference in ${\alpha}$-glucosidase inhibitory activity. The pancreatic lipase inhibitory activity showed relatively higher in the methanol extract than water extract except pericarp of Citrus junos. The DPPH radical scavenging activity of selected plants was much difference between measured plant species, and showed that the increase was proportional to the concentration. These results suggested that selected plants had the potent biological activity on carbohydrate, lipid Inhibitory activity and antioxidant activity, therefore these plant resources could be a good materials to develop medicinal preparations, nutraceuticals or health functional foods for diabetes or obesity.

• Nutrition Research and Practice
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• v.5 no.5
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• pp.389-395
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• 2011

In the present study, a suitable drying method was developed for citrus press cakes (CPCs), which are produced as a by-product in citrus juice plants, and the protective effect of methanol extract of CPCs prepared by far-infrared radiation (FIR) drying against $H_2O_2$-induced DNA damage was evaluated versus that of freeze-dried CPCs. Methanol extract of FIR-dried CPCs exhibited comparatively good ROS scavenging activity versus the freeze-dried CPCs at the concentration of 100 ${\mu}g$/mL. The extract strongly enhanced the cell viability against $H_2O_2$-induced oxidative damage in Vero cells. Lipid peroxidation inhibitory activity of the extract from FIR-dried CPCs was comparable to that of the extract from freeze-dried CPCs. This sample also exhibited good protective effects against $H_2O_2$-mediated cell apoptosis as demonstrated by decreased apoptotic body formation in the nuclear staining with Hoechst 33342. In the comet assay, the CPC extracts exhibited strong inhibitory effects against $H_2O_2$-mediated DNA damage in a dose-dependent manner. Thus, this study demonstrated that FIR drying effectively preserves CPC as a functionally important natural antioxidant source and the FIR drying can be adapted for drying CPCs and is more economical for massive production than freeze drying.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.983-988
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• 2005

Effects of Citrus sunki peel and its fermented product extracts on physiological and functional activities of cellular systems were investigated. Ethanol extract of Citrus sunki peel showed potent ROS-scavenging activity using 2',7'-Dichlorofluorescin diacetate as a fluorescent ROS probe in HepG2 cells. Fermented product of C. sunki peel extract markedly suppressed nitric oxide production in lipopolysaccharide (LPS)-activated RAW264.7 murine macrophage cells. Treatment with fermented product of C. sunki peel extract decreased intracellular protein levels of inducible nitric oxide synthase and cyclooxygenase II stimulated by LPS. High doses of fermented product lend to apoptotic cell death in CHO-IR cells.

• Journal of Food Hygiene and Safety
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• v.33 no.4
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• pp.255-258
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• 2018

The objective of this study was to investigate the inhibitory effect of natural antimicrobials on Listeria monocytogenes isolated from Korean slaughterhouses. A mixture of 15 strains of L. monocytogenes at low (3 Log CFU/mL) or high (7 Log CFU/mL) concentration was exposed to various extracts (grapefruit seed extract, citrus fruit extract, ginger extract, pear extract, Japanese apricot concentrate, balloon flower extract, jujube extract, and omija extract) at $0.001-4.0{\mu}g/mL$. Ginger extract, pear extract, Japanese apricot concentrate, balloon flower extract, jujube extract, or omija extract showed no antimicrobial effects on high-concentration of L. monocytogenes (7 Log CFU/mL). However, grapefruit seed extract and citrus fruit extract showed antibacterial effects against L. monocytogenes at 3 and 7 Log CFU/mL with MBCs of 0.001 and $0.002{\mu}g/mL$, respectively. These results indicate that grapefruit seed extract and citrus fruits extract can be used to control L. monocytogenes as natural antimicrobials.

• Journal of fish pathology
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• v.33 no.2
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• pp.177-184
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• 2020

In an attempt to find a feed additive showing an anti-scuticociliate effect, extracts from Citrus unshiu Peel were tested against virulent scuticociliate infection. The most effective anti-scuticociliate killing activity in vitro was observed in the extract squeezed from homogenizing water-soaked dried tangerine peel (DTP). In addition, we have investigated the effect of DTP as a feed additive on growth rate and anti-parasitic activity of olivaceus flounder. DTP extract added diets (0.1, 0.5, 1, and 5%/feed weight) were fed to flounder for 7 days for checking a growth rate and 14 days for a challenging test. As a result, the feed conversion rate was significantly improved only in 1% DPT extract group compared to the control and 0.5% DTP extract fed group showed 100% of survival rate in the challenge test, all of which indicating that DTP extract would be a potential feed additive against scuticociliatosis.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.373-378
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• 2008

Contents of phytochemicals in citron (Citrus junos Sieb. ex Tanaka) seeds and their effects on antioxidant activities were investigated. Methanol extract of defatted citron seeds contained the highest amounts of total polyphenols followed by 70% ethanol and water extracts. Neohesperidin was the most predominant citrus flavanones in these extracts. The highest amounts of limonoids were found in methanol extract, and this extract was the most efficient in scavenging both DPPH and ABTS radicals. All 3 extracts also exhibited good antioxidant activities against attack of linoleate free radicals on $\beta$-carotene. When methanol extract was sequentially fractionated into ether, ethyl acetate, n-butanol, and water fractions, butanol fraction contained the highest amounts of polyphenols otherwise most of limonoids were concentrated in ethyl acetate fraction. A positive relationship between radical scavenging activities and total polyphenol contents in fractions was observed while antioxidant activity on $\beta$-carotene seemed more related with contents of limonoids and other hydrophobic polyphenols.

• Food Science and Preservation
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• v.10 no.3
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• pp.388-393
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• 2003

Citrus peel extract was prepared using 70％ ethanol solution by two extraction conditions (20$^{\circ}C$ for 72 hours and 85$^{\circ}C$ for 3 hours). The effect of gamma-irradiation on the changes of physiological activity also investigated at 0, 5, 10 and 20 kGy of absorbed doses. Color characteristics, DPPH radical scavenging, tyrosinase inhibition and nitrite scavenging activities of the extracts were measured at 41$^{\circ}C$ for 30 days. Color values were different by extraction methods at the initial stage, which heat-extracted sample had lower L$\^$＊/ - but higher a$\^$＊/ - and b$\^$＊/ -values than those extracted at room temperature. Irradiation changed color of the extract lighter by increasing Hunter color L$\^$＊/ - and a$\^$＊/ -values. DPPH radical scavenging, tyrosinase inhibition and nitrite scavenging activities were not affected by either extraction methods or irradiation but significantly reduced by storage time. Therefore, when the cost-effective extraction methods is selected, the citrus peel extracts, which is a major byproduct in citrus processing, could be used as a functional material in various applications.