Younghwa Kim

Prof. Younghwa Kim

Kyungsung University, Busan, South Korea
orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 April 2024 in Antioxidants
Verified
Journal Article
Open access
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JLJinyeong Lim
Jinyeong Lim
HLHana Lee
Hana Lee
SHSeonghwa Hong
Seonghwa Hong
Jun-Soo LeeJun-Soo Lee
Jun-Soo Lee
Younghwa KimYounghwa Kim
Younghwa Kim
We comparatively evaluated the antioxidant properties of key triterpenes from Centella asiatica, including asiatic acid (AA), asiaticoside, madecassic acid, and madecassoside, in several cell types, including skin fibroblasts, macrophages, hepatocytes, and endothelial cells, under conditions promoting oxidative stress. AA conferred the highest viability on Hs68 cells exposed to ultraviolet B (UVB) irradiation. Triterpene pretreatment attenuated the UVB-induced generation of reactive oxygen species (ROS) and malondialdehyde (MDA), as well as the UVB-induced depletion of glutathione (GSH) in skin fibroblasts. AA most potently inhibited UVB-induced MMP generation, resulting in increased intracellular collagen levels. Pretreatment with triterpenes, particularly AA, significantly improved cell viability and attenuated TBHP-induced levels of ROS, alanine aminotransferase, and aspartate aminotransferase in HepG2 cells. Triterpenes attenuated ROS levels and reduced MDA and GSH expression in EA.hy926 cells. In RAW264.7 macrophages, production of nitric oxide, tumor necrosis factor-α, and interleukin-6 (indicators of LPS-induced oxidative damage) was significantly reduced by treatment with any of the triterpenes. Statistical analyses of triterpene biological activities using principal component analysis and hierarchical clustering revealed that AA exerted the greatest overall influence and showed remarkable activity in Hs68 and HepG2 cells.

25 May 2020 in Nutrients
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Journal Article
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YJYang Jinwoo
Yang Jinwoo
Jun-Soo LeeJun-Soo Lee
Jun-Soo Lee
Younghwa KimYounghwa Kim
Younghwa Kim
The present study evaluated the effects of acid-treated rutin on hyperlipidemia and obesity in high-fat diet (HFD)-induced obese mice. The mice consumed a HFD with or without acid-treated rutin for 7 weeks. Body weight gain considerably decreased, by approximately 33%, in the acid-treated rutin (AR) and quercetin (Q) groups compared to that in the HFD group. The adipocytes’ size in epididymal fat in AR and Q groups was significantly reduced compared to that in the HFD group (p < 0.05). Treatment with AR decreased the levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol compared to the HFD group. In particular, administration of AR significantly decreased serum triglyceride (36.82 mg/dL) by 46% compared to HFD (69.30 mg/dL). The AR group also showed significantly decreased atherogenic indices and cardiac risk factors. These results suggest that deglycosylated rutin generated by acid treatment enhances the anti-obesity and hypolipidemic effects in obese mice, and provides valuable information for improving the functional properties of glycosidic flavonoids.

13 December 2019 in Antioxidants
Verified
Journal Article
Open access
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HLHana Lee
Hana Lee
JSJeehye Sung
Jeehye Sung
Younghwa KimYounghwa Kim
Younghwa Kim
HJHeon Sang Jeong
Heon Sang Jeong
Jun-Soo LeeJun-Soo Lee
Jun-Soo Lee
Unsaponifiable matter (USM) from perilla seed meal contains numerous phytochemicals, including tocopherols, phytosterols, squalene, and policosanols, that exhibit antioxidant and health-promoting properties. In this study, the protective effects of USM on UVB-induced skin aging were investigated in Hs68 cells. UVB irradiation decreased cell viability by 26% compared to the control. However, USM blocked UVB-induced cytotoxicity. Moreover, USM treatment significantly decreased the UVB-induced production of reactive oxygen species and attenuated the UVB-induced production and mRNA expression of matrix metalloproteinases (MMPs) by inhibiting the phosphorylation of mitogen-activated protein kinases and activator protein 1 (AP-1). Furthermore, UVB exposure led to a 49.4% reduction in collagen synthesis. However, USM treatment restored collagen synthesis through upregulation of the transforming growth factor beta (TGF-β)/Smad2/3 pathways. These data indicate that USM regulates the production of MMPs and collagen by modulation of the TGF-β/Smad pathway and AP-1 activity, suggesting that USM may be a useful anti-photoaging ingredient.

22 July 2024 in Frontiers in Nutrition
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Journal Article
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SPSamuel Park
Samuel Park
HKHeon-Woong Kim
Heon-Woong Kim
CLChang Joo Lee
Chang Joo Lee
Younghwa KimYounghwa Kim
Younghwa Kim
JSJeehye Sung
Jeehye Sung
Volatile sulfur compounds (VSCs) are not only important for their therapeutic potential but also significantly influence the flavor profiles of agricultural products. VSCs exhibit various chemical structures due to their stability and volatility, and they may form or be altered as a result of enzymatic and chemical reactions during storage and cooking. This study has focused on profiles of VSCs in 58 different vegetable samples by using HS-SPME-GC/MS technique and chemometric analyses. The validation was carried out using cabbage juice as a vegetable matrix for VSCs analysis, showing satisfactory repeatability (RSD 8.07% ~ 9.45%), reproducibility (RSD 4.22% ~ 7.71%), accuracy and specificity. The established method was utilized on various vegetables, revealing that 21 VSCs such as sulfides, disulfides, trisulfides, isothiocyanates, sulfhydryls, and thiophenes were successfully identified and quantified. These compounds were found in a range of vegetables including Allium species, Cruciferae, Capsicum species, green leafy vegetables, and mushrooms. In particular, isocyanate and allyl groups were abundant in Cruciferae and Allium vegetables, respectively. Cooking conditions were shown to reduce the levels of certain sulfur compounds such as dimethyl sulfide and dimethyl trisulfide in vegetables like broccoli and cabbage, suggesting that heat treatment can lead to the volatilization and reduction of these compounds. The present study provides reliable insights into the compositions of VSCs in various vegetables and examines the changes induced by different cooking methods.

1 January 2020 in Evidence-Based Complementary and Alternative Medicine
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SHSungwha Hong
Sungwha Hong
Younghwa KimYounghwa Kim
Younghwa Kim
JSJeehye Sung
Jeehye Sung
HLHana Lee
Hana Lee
HHHuijin Heo
Huijin Heo
Jun-Soo LeeJun-Soo Lee
Jun-Soo Lee
This study aimed at evaluating the cytoprotective activity of jujube water extract (JWE) against alcohol‐induced oxidative stress via the activation of the Nrf2 pathway in HepG2 cells. JWE had various phenolic compounds, and the vanillic acid content was the highest in the extract. To determine the cytoprotective effect of JWE against alcohol‐induced damage, hepatocytes were treated with JWE and 3% ethanol. JWE (100 μg/mL) markedly increased cell viability by approximately 100% in a dose‐dependent manner. Moreover, JWE attenuated the production of malondialdehyde, reactive oxygen species, aspartate, and alanine aminotransferase and the depletion of glutathione. Moreover, JWE enhanced the expression of antioxidant defense enzymes including heme oxygenase‐1, NADPH quinone oxidoreductase 1, and γ‐glutamate‐cysteine ligase catalytic against alcohol‐induced oxidative damage in hepatocytes via the activation of Nrf2. Taken together, JWE possesses the protective effect against alcohol‐induced oxidative injury in hepatocytes through the upregulation of the Nrf2 signaling pathway. Therefore, jujube fruit might have the potential to improve alcohol‐related liver problems.

8 March 2021 in Antioxidants
Verified
Journal Article
Open access
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HHhuijin heo
huijin heo
HLHana Lee
Hana Lee
JYJinwoo Yang
Jinwoo Yang
JSJeehye Sung
Jeehye Sung
Younghwa KimYounghwa Kim
Younghwa Kim
Jun-Soo LeeJun-Soo Lee
Jun-Soo Lee
Ginseng seeds are rich in phytosterols, ginsenosides, and fatty acids, and can therefore be used in skincare to delay the aging process. Ginseng seed embryo (GSE) and ginseng seed coat (GSC) were separated from ginseng seeds (Panax ginseng Meyer). This study evaluated the protective activity and underlying mechanism of GSE and GSC on UVB irradiation-induced skin photoaging using Hs68 cells. Their bioactive compounds, including phytosterols, ginsenosides, tocopherols, tocotrienols, and fatty acids were determined by HPLC and GC. The levels of reactive oxygen species, matrix metalloproteinases (MMPs), and collagen levels were measured in human dermal fibroblast cell line, Hs68 cells. The antioxidant capacity and contents of total polyphenols and flavonoids were higher in GSC than those in GSE. Linoleic acid was the major fatty acid in both GSE and GSC. GSE and GSC treatment alleviated UVB-induced increase of reactive oxygen species (ROS), matrix metalloproteinase (MMP)-1, and MMP-3, resulting in reduced collagen degradation. Increased UVB-mediated phosphorylation of mitogen activated protein kinase (MAPK) and activator protein-1 (AP-1) was inhibited by GSE and GSC treatment. Moreover, GSE and GSC effectively upregulated transforming growth factor-β (TGF-β) 1 levels. It was found that ginseng seeds regulate the expression of TGF-β/Smad and MAPK/AP-1 pathways. Ginseng seeds contain various bioactive compounds and have protective activity against UVB-induced skin photoaging. Therefore, ginseng seeds have the potential for use in cosmeceutical preparations.