• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1214-1220
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• 2016

This study compared antioxidant compounds and antioxidant activities according to various varieties of 18 colored rice. Selected rice cultivars for this study were as follows: black rice (12 cultivars)-Heugjinjubyeo, Nunkeunheugchal, Joeunheugmi, Josaengheugchal, Heuggwang, Heugseol, Shinmyeongheugchal, Shinongheugchal, Shintoheugmi, Cheongpungheukchal, Heughyang, Boseogheugchal, red rice (four cultivars)-Jeogjinju, Jeogjinjuchal, Hongjinju, Geonganghongmi, and green rice (two cultivars)-Nogwonchal and Jungmo1020. These were transplanted on June 30th and cultivated from the Department of Southern Area Crop Science, National Institute of Crop Science in Miryang, Korea. Total polyphenol (TP) content of black rice cultivars was higher than that of red rice varieties. Heugjinjubyeo exhibited the highest TP, which was $9.55{\pm}0.05mg$ gallic acid equivalent/g sample. There were no significant differences between black rice cultivars and red rice cultivars in terms of total flavonoid (TF) level. Heugjinjubyeo and Hongjinju showed the higher TF content than any other variety. Shintoheugmi revealed the highest anthocyanin content ($194.26{\pm}0.65mg/100g$). Methanol extract of Heugjinjubyeo had the highest antioxidant activities. 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activities of Heugjinjubyeo extract were $14.70{\pm}0.62$ and $30.68{\pm}2.22{\mu}g/mL$, respectively. There were significant correlations between antioxidant compound content and antioxidant activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1653-1659
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• 2015

This study compared physicochemical properties and antioxidant activities according to different harvest times in five varieties of black rice (BR). Five cultivars of BR, Nunkeunheukchal (NKHC), Sinnongheugchal (SNHC), Sintoheugmi (STHM), Josaengheugchal (JSHC), and Heugjinju (HJJ), were selected for the study. Cultivars were transplanted on June 20th and cultivated by the Department of Southern Area Crop Science, NICS in Miryang, Korea. Heading dates of NKHC, SNHC, STHM, JSHC, and HJJ were Aug. 17th, Aug. 30th, Sep. 1st, Aug. 20th, and Aug. 12th, respectively. The five different harvest times were as follows; 35, 40, 45, 50, and 55 days after heading date. The highest level of anthocyanin was 35 days after heading date in all varieties. Levels of anthocyanin in NKHC, SNHC, STHM, JSHC, and HJJ were 164, 203, 251, 67, and 210 mg/100 g, respectively. Content of anthocyanin significantly decreased 35 days after heading in four varieties, excluding JSHC. Highest DPPH $IC_{50}$ values were 57, 29, 10, and $27{\mu}g/mL$ in NKHC, SN HC, STHM, and JSHC extracts, respectively. Highest ABTS $IC_{50}$ values were 24, 13, 9, and $11{\mu}g/mL$ in NKHC, SNHC, STHM, and JSHC extracts, respectively. The antioxidant activities were highest 35 days after the heading date and significantly decreased in four varieties, excluding HJJ. The antioxidant activity of HJJ showed no significant difference, according to harvest time. This study suggests that the content of anthocyanin and antioxidant activity could be considered as factors affecting optimal harvest period to produce highly qualified black rice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.562-571
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• 2017

In this study, we investigated the anti-oxidant activities [electron-donating ability (EDA), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging ability, and reactive oxygen species (ROS) inhibitory activity], anti-wrinkle activities [collagenase inhibitory activity, suppression and/or phosphorylation of matrix metalloproteinases (MMPs), and mitogen-activated protein (MAP) kinase activity], and mRNA expression levels using reverse transcription-polymerase chain reaction (RT-PCR) assay in ultraviolet (UV) B ray ($50mJ/cm^2$)-irradiated human keratinocyte HaCaT cells. Josaengheugchal, Sinneungheugchal (SE), Shintoheug rice, Heugjinju rice, and Heugseol (HE) among colored rice varieties were reported to have excellent antioxidant properties. In the EDA and ABTS radical scavenging assays, extracts of the five colored rice varieties had scavenging activities of 72% at concentrations higher $50{\mu}g/mL$. In the collagenase inhibition assay, ethanol extracts of the five colored rice varieties showed high inhibitory effects of about 60% at concentrations higher $25{\mu}g/mL$. In the ROS inhibition assay, ethanol extracts of HE and SE showed very excellent inhibition efficacies at all concentrations. We determined molecular biological mechanisms of MMPs (MMP-1, -3, -8, and -13) and mitogen-activated protein kinase (MAPK) with HE, and the results show that HE suppressed expression of MMPs and phosphorylation of MAPK and increased expression of pro-collagen type I in UVB-irradiated cells. It was also confirmed by RT-PCR that HE reduced expression of MMPs mRNA. Therefore, these results suggest that HE has anti-wrinkle and collagen production effects and may be used as a material in the development of functional food and cosmetic industries.