• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.91-91
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• 2019

Hibiscus syriacus L. is widely distributed throughout Eastern and Southern Asia and its root bark has been used as a traditional remedy. Recently, the extracts of H. syriacus L. exerts anti-cancerous, anti-microbial, and anti-inflammatory activities. However, the effect of anthocyanin-rich fraction of H. syriacus L. petals (PS) has not been studied under excessive oxidative stress. In this study, we evaluated the cellular protective effect of PS in HaCaT human skin keratinocytes under hydrogen peroxide ($H_2O_2$)-induced oxidative stress conditions. PS at below $400{\mu}g/ml$ did not show any cell death; however, over $800{\mu}g/ml$ of PS gradually increased cell death. PS at below $400{\mu}g/ml$ significantly inhibited $H_2O_2$-induced apoptosis in HaCaT cells concomitant with downregulation of Bax and upregulation of pro-PARP and p-Bcl-2. Additionally, PS remarkably reversed $H_2O_2$-induced excessive reactive oxygen species (ROS) production and apoptosis, and also significantly inhibited mitochondrial ROS production concomitant with suppression of $H_2O_2$-induced mitochondrial depolarization. $H_2O_2$-mediated ratio of Bax to Bcl-2, and caspase-3 activation were markedly abolished in the presence of PS. Moreover, the inhibition of HO-1 function using zinc protoporphyrin, an HO-1 inhibitor, significantly attenuated the cellular protective effects of PS against $H_2O_2$, indicating the significance of HO-1 in PS mediated cytoprotective effect, which was mediated by activating nuclear factor erythroid 2-related factor-2 (Nrf2). Taken together, our results suggest that cytoprotective effect of PS in HaCaT keratinocytes against oxidative stress-induced apoptosis is mediated by inhibiting cellular and mitochondrial ROS production, which is downregulated by activating Nrf2/HO-1 axis.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.400-407
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• 2013

This study was performed to analyze the effect of light quality of discharge lamp on growth and phytochemicals contents of lettuce (Lactuca sativa L. cv. Jeokchima) grown under metal halide (MH) lamp, high-pressure sodium (HPS) lamp, and xenon (XE) lamp in a plant factory. Cool-white fluorescent (FL) lamp was used as the control. Photoperiod, air temperature, relative humidity, $CO_2$ concentration, and photosynthetic photon flux (PPF) in a plant factory were 16/8 h (day/night), $22/18^{\circ}C$, 70%, 400 ${\mu}mol{\cdot}mol^{-1}$, and 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. MH lamp had the greatest fraction of blue light (400-500 nm) of 23.0%. However, HPS lamp had the lowest fraction of 4.7% for blue light and the greatest fraction of 38.0% for red light (600-700 nm). At 11 and 21 days after transplanting, leaf length, leaf width, leaf area, shoot fresh weight, and shoot dry weight of lettuce as affected by the light quality of the discharge lamp were significantly different. The leaf area of lettuce grown under HPS, MH, and XE lamp increased by 45.7%, 16.3%, and 9.5%, respectively, as compared to the control. These results were similar for shoot fresh weight. Growth characteristics of lettuce grown under HPS lamp increased since HPS lamp had more fraction of red light. However, growth of lettuce grown under MH and XE lamp decreased since they had more fraction of blue light. As compared to the control, the ascorbic acid in lettuce leaves grown under discharge lamp decreased. The greatest anthocyanins accumulation of 0.70 mg/100 g was found at MH treatment. Anthocyanins content in lettuce leaves grown under XL and HPS lamp were 79.3% and 8.6%, respectively, compared with the control. Growth and phytochemicals contents of lettuce were highly affected by the different spectral distribution of the discharge lamp. These results indicate that the combination of discharge lamp or LED lamp for enhancing the light quality of discharge lamps is required to increase the growth and phytochemicals accumulation of lettuce in controlled environment such as plant factory.

• Korean Journal of Food Science and Technology
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• v.48 no.3
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• pp.284-288
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• 2016

To investigate the physiological effect of Hibiscus sabdariffa, in vitro antioxidant activities and neuroprotective effects against high glucose-induced oxidative stress were examined. The ethyl acetate fraction (EtOAc-Fr) from H. sabdariffa contained high total phenolic contents compared with other fractions but total anthocyanin contents were lower than 80% Ethanol extract showed the highest 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical scavenging activity and malondialdehyde inhibitory effect. Furthermore, the EtOAc-Fr decreased the intracellular reactive oxygen species level, and protected the neuron-like PC12 cells from high glucose-induced cytotoxicity. The EtOAc-Fr also presented inhibitory effects against acetylcholinesterase as an acetylcholine hydrolase enzyme. Finally, chlorogenic acids as main phenolics by high performance liquid chromatography analysis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.3
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• pp.381-388
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• 2014

The antioxidant activities of extracts from Rubus coreanus Miquel (black raspberry) and Morus alba L. (mulberry) fruits were investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 2,2-azino-bis-(3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS) assay, and reducing power assay. Aqueous mixtures of ethanol, methanol, and acetone were analyzed in order to determine the most effective extraction solvent for the two fruits. Black raspberry and mulberry extracts with the 60:40 acetone-water mixtures (v/v) showed the highest DPPH radical scavenging activities (56.2 and 85.2%, respectively) compared to the other extraction solvents. The 60% acetone extract was finally selected as an extraction solvent and then sequentially fractionated according to solvent polarity. Among the fractions of the two fruits, the ethyl acetate fraction showed the highest antioxidant activity as well as total phenolic and total flavonoid contents. In addition, there were high correlation coefficients between antioxidant activities and their contents. The $EC_{50}$ value of the ethyl acetate fraction from mulberry fruit was 2.2 times lower than that of butylated hydroxytoluene (BHT) in DPPH assay. The major phenolic acid and anthocyanin of the two fruits were protocatechuic acid and cyanidin-3-glucoside, respectively.