• Food Science and Biotechnology
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• v.15 no.3
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• pp.357-362
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• 2006

We assessed various antioxidant activities, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2'-azino-bis 3-ethylbenz-thiazoline-6-sulfonic acid (ABTS) radical, and reactive oxygen species (ROS) radical scavenging effect, along with antioxidant capacity, of soybean oil with added Citrus species peel extracts (CPEs). These extract oils showed higher radical scavenging effects than grape fruit seed extract, the natural antioxidant agent, did. When CPEs were added to soybean oil, they showed peroxide value (POV) and acid value (AV) increasing inhibition effects. Furthermore, none of the CPEs showed any cytotoxicity over the tested concentration range of 0.01-100 ppm. The major flavonoid contents of Citrus junos, as determined by HPLC, were naringin ($7.5\;{\mu}g/mg$) and neohesperidin ($7.5\;{\mu}g/mg$), and those of Citrus unshiu were narirutin ($3.13\;{\mu}g/mg$) and hesperidin ($1.97\;{\mu}g/mg$). However, the aglycone form was not found. This study showed that CPEs might be a potent source of natural antioxidant, without any toxic effects.

• Korean Journal of Plant Resources
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• v.10 no.3
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• pp.213-220
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• 1997

The present study has been undertaken to characterize availability of citrus as a medicinal plant with antineoplastic property. The crude extracts from 40 species of fruits with 12 species of the local Citrus in Cheju island were evaluated on their potential activities against mouse P388 lymphocytic leukaemia in vitro. The percent cytotoxicity varied from 25.40 to 97.94% at a concentration of $100{\mu}g/mL$. Among 40 spp., 8 species showed high toxicity more than 90% against P388 cells and Cheongkyool(C. nippokoreana) exhibited the most cytotoxicity as 97.94%($IC_{50}=20.2{\mu}g/mL$). Nine varieties of C. junos were showed insiginicant cytotoxicity. In trifoliate orange, immature fruit was stronger than mature and peel extract showed higher cytotoxicity($IC_{50}=18{\mu}g/mL$) than the other tissues. Hexane fraction from methanol(MeOH) extract of trifoliate orange showed highly significant inhibition of cell growth($IC_{50}=3.9{\mu}g/mL$). In addition, its cytotoxicity increased remarkably from 3.95 to $0.40{\mu}g/mL$ as exposure time legthened. Cytotoxic activities of crude extracts were decreased considerably during a six months storage period. It was apparent that there is considerable variation in cytotoxicity, depending upon species, maturity and storage time of extracts. There was no meaningful cytotoxic difference between archicitrus and metacitrus in the genus Citrus.

• 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.

• Plant Disease and Agriculture
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• v.5 no.2
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• pp.100-104
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• 1999

A total of 65 isolates of Penicillium were isolated from decayed post-harvest fruits of apple pear citrus and grape. The Penicillium species isolated from the apple were idnetified as P. aurantiogriseum and P. expansum those from the pear were P. crustosum and P. expansum and those from the grape were P. aurantiogriseum and P. expansum, From decayed citrus fruits. P. digitatum and P. italicum were isolated. Citrinin and patulin from these species in the YES(yeast extract sucrose) broth were extracted with ethyl acetate and purified by thin-layer chromatography(TLC) and high performance liquid chromatography(HPLC) Among 51 isolates of Penicillium from apple pear and grape 7 isolates produced citrinin 13 isolates produces patulin and 12 isolates produced citrinin and patulin also. All 14 isolates of Penicillium from citrus produced only patulin.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.312-316
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• 2006

Crude extract of young dangyuja (Citrus grandis Osbeck) fruit was investigated for its antioxidant activity as measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. Among the samples, including 4 Citrus species and various solvent-extracted-fractions of young dangyuja fruit, the water-extracted fraction (WF) and butanol-extracted fraction (BF) showed the greatest DPPH free radical scavenging activity. WF and BF were further examined for their antioxidant activities by three different in vitro assays. The cell viability tests using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay showed that both fractions significantly reduced $H_2O_2$-induced cytotoxicity in HepG2 cells dose-dependently. Generation of the reactive oxygen species (ROS) was also reduced in cells pretreated with both fractions. In addition, BF showed a higher level of lipid peroxidation inhibitory capacity than WF in $H_2O_2$-treated HepG2 cells. Taken together, these results indicate that young dangyuja fruit can be used as an easily accessible source of natural antioxidants.

• Proceedings of the Plant Resources Society of Korea Conference
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• v.18 no.1
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• pp.41-51
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• 2005

We examined whether extracts from 14 local citrus spp. on Jeju Island (Korea) contained chemosensitizing activity that would increase the cytotoxic effect of vincristine(VCR) in drug-resistant cancer cells. We report that methanol extracts from fruits and flowers of some species had a chemosensitizing effect that reversed P-glycoprotein (Pgp)-mediated multidrug resistance (MDR). Using drug-sensitive AML-2/WT and drug-resistant AML-2/D100 in the absence of VCR in human acute myelogenous leukemia cells we found that fruit or flower extracts alone generally had low cytotoxicity $(IC_{50}>200\;{\mu}g/ml)$. In studies examining the effect of extracts on 120 ng/ml VCR cytotoxicity in drug-resistant AML-2/D100 cells, we found that immature fruit extracts had greater chemosensitizing activity than either extracts from mature fruit or flower. Of the 14 species examined, the immature fruit extract from Inchangkyool (Citrus ichangiensis) showed the hishest chemosensitizing index(CI) valus. Immature fruit extracts of Hongkyool(C. tachibana), Byungkyool(C. platymamma), Cheongkyool(C. nippokoreana) and Jinkyool (C. sunki) also strongly potentiated VCR cytotoxicity in AML-2/D100 cells. The chemosensitizing effect of peel extracts was 2-10-fold that of whole fruit extracts from Hongkyool (C. tachibana), Byungkyool (C. platymamma) and Inchangkyool (C. inchangiensis). The CI values for flower extracts were higher than those for mature fruit extracts, but lower than those for immature fruit extracts. These results indicate that immature citrus fruits contain compounds that do not exert their activity solely through cytotoxicity. In particular, Incahngkyool (C. inchangiensis), Byungkyool(C.platymamma), Cheongkyool(C. nippokoreana) and Hongkyool (C. tahibana) may be useful sources of chemosensitizing compounds.

• Journal of Nutrition and Health
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• v.48 no.5
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• pp.451-456
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• 2015

Purpose: Neuronal apoptotic events induced by aging and hypoxic/ischemic conditions is an important risk factor in neurodegenerative diseases such as ischemia stroke and Alzheimer's disease. The peel of Citrus sunki Hort. ex Tanaka has long been used as a traditional medicine, based on multiple biological activities including anti-oxidant, anti-inflammation, and anti-obesity. In the current study, we examined the actions of fermented C. sunki peel extract against cobalt chloride ($CoCl_2$)-mediated hypoxic death in human neuroblastoma SH-SY5Y cells. Methods: Cell viability was measured by trypan blue exclusion. Expression of apoptosis related proteins and release of cytochrome c were detected by western blot. Production of intracellular reactive oxygen species (ROS) and apoptotic morphology were examined using 2',7'-dichlorofluorescin diacetate (DCF-DA) and 4',6-diamidino-2-phenylindole (DAPI) staining. Results: Exposure to $CoCl_2$, a well-known mimetic agent of hypoxic/ischemic condition, resulted in neuronal cell death via caspase-3 dependent pathway. Extract of fermented C. sunki peel significantly rescued the $CoCl_2$-induced neuronal toxicity with the cell viability and appearance of apoptotic morphology. Cytoprotection with fermented C. sunki peel extract was associated with a decrease in activities of caspase-3 and cleavage of poly (ADP ribose) polymerase (PARP). In addition, increase in the intracellular ROS and release of cytochrome c from mitochondria to the cytosol were inhibited by treatment with extract of fermented C. sunki peel. Conclusion: Based on these data, fermented C. sunki peel extract might have a protective effect against $CoCl_2$-induced neuronal injury partly through generation of ROS and effectors involved in mitochondrial mediated apoptosis.

• Korean Journal of Soil Science and Fertilizer
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• v.51 no.1
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• pp.28-34
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• 2018

Yuzu (Citrus junos) gummosis disease, caused by Phytophthora nicotianae, was first reported in 1997. As known in citrus, Phytophthora is the most fastidious soil-borne pathogen to control. In order to minimize its damage to Citrus spp., integrated pest management (IPM) approach, including fungicide chemicals and resistant cultivars, is necessary. Therefore, in this study we tried to evaluate tolerance of yuzu cultivars and its related species against yuzu Phytophthora. Trifoliate orange was evaluated as a susceptible host to yuzu Phytophthora by both mycelial growth onto extract media and immature fruit inoculation. However, in zoospores spray-inoculation on 2-year-old cuttings tree, trifoliate orange appeared to have a resistant property as showing less than 6% diseased leaf rate. Among yuzu cultivars only 'Namhae No. 1' appeared resistant property against both P. nicotianae and P. citrophthora. The 'Namhae No. 1' showed 5.7% and 10.6% diseased leaf ratio by P. nicotianae and P. citrophthora, respectively. Clearly, in order to reduce damages caused by two yuzu Phytophthora, we suggest that growers may utilize a trifoliate orange as a rootstock and 'Namhae No. 1' as a scion for fruit production.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1086-1091
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• 2008

The antioxidant activities of the extracts of dangyuja (Citrus grandis Osbeck) leaves were evaluated. The highest phenolic content was obtained from the ethyl acetate fraction (EF) (202.1$\pm$0.8 mg GAE/g dried extract) and it exhibited the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. The cytoprotective effects of EF on oxidative damage induced by tert-butyl hydroperoxide (t-BHP) in a human hepatoma cell line, HepG2 cells, were investigated to understand the intracellular antioxidant mechanisms. Treatment of HepG2 cells with EF prior to oxidative stress was found to inhibit reactive oxygen species (ROS) generation, lipid peroxidation, and DNA damage in a dose-dependent manner. Gas chromatography-mass spectrometry (GC-MS) studies on EF resulted in tentative identification of 19 compounds representing 94.3% of the total content. Taken together, these results demonstrated that EF has excellent antioxidant activities and thus dangyuja leaves have great potential as a source for natural antioxidant which can be applied in food products.

• Journal of dental hygiene science
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• v.6 no.4
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• pp.309-311
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• 2006

In order to development of new denture cleaners using natural antimicrobial agents, we have investigated various species of medicinal plants for the antimicrobial activity against Streptococcus matans and Candida albicans. Citrus extract showed significant antifungal activities in a dose-dependent manner against Candida albicans. Candidasis is also a common problem affecting older adults using full denture. We also developed liquid type denture cleaner formulation using citrus extracts.