• Microbiology and Biotechnology Letters
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• v.47 no.2
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• pp.195-200
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• 2019

The purpose of this study was to investigate the melanogenesis inhibiting activity of the ethanol extract from Polygonum amphibium L. Firstly, the n-hexane (Hx), chloroform ($CHCl_3$), ethyl acetate (EA), n-butanol (BuOH), and water (Water) fractions were isolated from the P. amphibium L. ethanol extract. The efficacy of melanogenesis was found to significantly decrease via the EA and BuOH fractions when compared to the control in B16F10 cells. EA particularly showed the lowest melanin content in B16F10 cells when compared to all the other extracts. Concentration-dependent inhibition of melanin synthesis was also observed in the EA fraction at concentrations below $50{\mu}g/ml$, which did not exhibit cytotoxicity in B16F10 cells. Notably, the expression of three key proteins (tyrosinase, tyrosinase-related protein-1 (TRP-1), and TRP-2), which are involved in melanogenesis, were significantly decreased via the EA fraction. EA also inhibited body pigmentation in vivo in a zebrafish model. Overall, we demonstrated melanogenesis suppression using the EA fraction from P. amphibium L., which could be a potential candidate for an antimelanogenesis agent.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.111-111
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• 2019

Glycyrrhizae radix is one of the most frequently prescribed ingredients in Oriental medicine, and G. radix extract has been shown to exert anti-cancer effects. However, the cellular and molecular mechanisms of apoptosis by G. radix are poorly defined. In the present study, it was examined the biochemical mechanisms of apoptosis by water extract of G. radix (WEGR) in human bladder T24 cancer cells. It was found that WEGR could inhibit the cell growth of T24 cells in a dose-dependent manner, which was associated with the induction of apoptotic cell death, as evidenced by the formation of apoptotic bodies, DNA fragmentation and increased populations of annexin-V positive cells. The induction of apoptotic cell death by WEGR was connected with an up-regulation of pro-apoptotic Bax protein expression and down-regulation of anti-apoptotic Bcl-2 and Bcl-xL proteins, and inhibition of apoptosis family proteins (XIAP, cIAP-1 and cIAP-2). In addition, apoptosis-inducing concentrations of WEGR induced the activation of caspase-9, an initiator caspase of the mitochondrial-mediated intrinsic pathway, and caspase-3, accompanied by proteolytic degradation of poly (ADP-ribose)-polymerase. WEGR also induced apoptosis via a death receptor-mediated extrinsic pathway by caspase-8 activation, resulting in the down-regulation of total Bid and suggesting the existence of cross-talk between the extrinsic and intrinsic pathways. Taken together, the present results suggest that WEGR may be a potential chemotherapeutic agent for the control of human bladder cancer cells.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.112-112
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• 2019

Baicalein is one of the main flavonoids derived from roots of Scutellaria baicalensis Georgi, a traditional Oriental medicine. Although baicalein has high antitumor effect on several human carcinomas, the mechanism responsible for this property is not unclear. In this study, the data revealed that baicale-ininduced growth inhibition was associated with the induction of apoptosis connecting with cytochrome c release, down-regulation of anti-apoptotic Bcl-xl and increased the percentage of cells with a loss of mitochondria membrane permeabilization. Baicalein also induced the proteolytic activation of caspases and cleavage of PARP; however, blockage of caspases activation by z-VAD-fmk inhibited baicalein-induced apoptosis. In addition, baicalein enhanced the formation of autophagosomes and up-regulated LC3-II/LC3-I ratio. Interestingly, the pretreatment of bafilomycin A1 recovered baicalein-induced cell death suggesting that autophagy by baicalein roles as protective autophagy. Taken together, our results indicated that this flavonoid induces apoptosis and cell protective autophagy. These data means combination treatment with baicalein and autophagy inhibitor might be a promising anticancer drug.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.113-113
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• 2019

Diallyl trisulfide (DATS) is an organic polysulfide compound found in garlic. Although certain studies have demonstrated that DATS possesses strong anti-inflammatory activity, the underlying molecular mechanisms remain largely unresolved. In this study, we examined whether DATS exerts anti-inflammatory activity and investigated the possible mechanisms. Our results indicated that DATS significantly suppressed the lipopolysaccharide (LPS)-induced release of nitric oxide (NO) and prostaglandin E2 by inhibiting inducible NO synthase and cyclooxygenase-2 expression at the transcriptional and post-transcriptional levels in RAW 264.7 macrophages. DATS also down-regulated Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 expression, and inhibited nuclear translocation of nuclear transcription factor-kappa B (NF-${\kappa}B$) in LPS-stimulated 264.7 macrophages. Furthermore, we found that these inhibitory effects of DATS were associated with the inhibition of chemokine receptor (CXCR4) and ligand (CXCL12) expression, and reactive oxygen species generation. Overall, the present data indicated that DATS had anti-inflammatory effects on LPS-activated macrophages, possibly via inhibiting the TLR4/NF-kB and/or chemokine signaling pathways, and DATS could be a potential drug therapy for inflammation and its associated diseases.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.76-76
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• 2020

Stachys sieboldii Miq. (chinese artichoke), which has been extensively used in oriental traditional medicine to treat of ischemic stroke; however, the role of Stachys sieboldii Miq. (SSM) in cerebral ischemia/reperfusion (I/R) injury is not yet fully understood. In the current study, the neuroblastoma cell line (SH-SY5Y) were subjected to oxygen-glucose deprivation/reperfusion (OGD/R) to simulate I/R injury in vitro model. The results showed that SSM improved OGD/R-induced inhibitory effect on cell viability of SH-SY5Y Cells. SSM displayed anti-oxidative activity as proved by the decreased levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and increased activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in OGD/R-induced SH-SY5Y Cells. In addition, cell apoptosis was markedly decreased after SSM treatment in OGD/R-induced SH-SY5Y Cells. The up-regulation of Bcl-2 and down-regulation of Bax, thus reducing the Bax/Bcl-2 ratio that in turn protected the activation of caspase-9 and -3, and inhibition of poly (ADP-ribose) polymerase cleavage, which was associated with the blocking of cytochrome c release to the cytoplasm. Collectively, SSM protected human neuroblastoma SH-SY5Y cells from OGD/R-induced injury via preventing mitochondrial-dependent pathway through scavenging excessive ROS, suggesting that SSM might be a potential agent for the ischemic stroke therapy.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.77-77
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• 2020

Purple loosestrife-Lythrum anceps (Koehne) Makino is a herbaceous perennial plant belonging to the Lythraceae family. It has been used for centuries in Korea and other Asian traditional medicine. It has been showed pharmacological effects, including anti-oxidant and anti-microbial effects. However, the mechanisms underlying its anti-cancer mechanisms are not yet understood. In this study, we investigated the mechanism of apoptosis signaling pathways by ethanol extract of Lythrum anceps (Koehne) Makino (ELM) in human leukemia U937 cells. Treatment with ELM significantly inhibited cell growth in a dose-dependent manner by inducing apoptosis, as evidenced by the formation of apoptotic bodies (ApoBDs), DNA fragmentation and increased populations of sub-G1 ratio. Induction of apoptosis by ELM was connected with up-regulation of death receptor (DR) 4 and DR5, pro-apoptotic Bax protein expression and down-regulation of anti-apoptotic Bcl-2 protein, and inhibitor of apoptosis protein (IAP) family proteins (XIAP, cIAP-1, survivin), depending on dosage. This induction was associated with Bid truncation, mitochondrial dysfunction, proteolytic activation of caspases (-3, -8 and -9) and cleavage of poly(ADP-ribose) polymerase protein. Therefore, our data indicate that ELM suppresses U937 cell growth by activating the intrinsic and extrinsic apoptosis pathways, and thus may have applications as a potential source for an anti-leukemic chemotherapeutic agent.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.58-58
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• 2021

Although hypoxic/ischemic injury is thought to contribute to the incidence of Alzheimer disease (AD), the molecular mechanism that determines the relationship between hypoxia-induced β-amyloid (Aβ) generation and development of AD is not yet known. In this study, we investigated the protective effects of Acorus gramineus Soland. (AGS) on oxygen-glucose deprivation/reoxygenation (OGD/R)-induced A β production in SH-SY5Y human neuroblastoma cells. Pretreatment of these cells with AGS significantly attenuated OGD/R-induced production of reactive oxygen species (ROS) and elevation of levels of malondialdehyde, nitrite (NO), prostaglandin E2 (PGE2), cytokines (TNF-α, IL-1β and IL-6) and glutathione, as well as superoxide dismutase activity. AGS also reduced OGD/R-induced expression of the apoptotic protein caspase-3, the apoptosis regulator Bcl-2, and the autophagy protein becn-1. Finally, AGS reduced OGD/R-induced Aβ production and cleavage of amyloid precursor protein, by inhibiting secretase activity and suppressing the autophagic pathway. Although supporting data from in vivo studies are required, our results indicate that AGS may prevent neuronal cell damage from OGD/R-induced toxicity.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.57-57
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• 2021

Oxygen glucose deprivation/re-oxygenation (OGD/R) induces neuronal injury via mechanisms that are believed to mimic the pathways associated with brain ischemia. Stachys sieboldii Miq. (Chinese artichoke), which has been extensively used in oriental traditional medicine to treat of ischemic stroke; however, the role of S. sieboldii Miq. (SSM) in OGD/R induced neuronal injury is not yet fully understood. The present research is aimed to investigate the protective effect and possible mechanisms of SSM extract treatment in an in vitro model of OGD/R to simulate ischemia/reperfusion Injury. Pretreatment of these cells with SSM significantly attenuated OGD/R-induced production of reactive oxygen species (ROS) by increasing GPx, SOD, and decreasing MDA. SSM decreased mitochondrial damage caused by OGD/R injury and inhibited the release of cyt-c from mitochondrion to cytoplasm in SH-SY5Y cells. Furthermore, neuronal cell apoptosis caused by OGD/R injury was inhibited by SSM, and SSM could decrease apoptosis by increasing ratio of Bcl-2/Bax and inhibiting caspase signaling pathway in SH-SY5Y cells. SSM demonstrated a neuroprotective effect on the simulated cerebral ischemia in vitro model, and this effect was the inhibition of mitochondria-mediated apoptosis pathway by scavenging of ROS generation. Therefore, SSM may be a promising neuroprotective strategy against ischemic stroke.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.6
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• pp.1310-1320
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• 1989

본 논문에서는 비교적 많은 계산이 수행되어온 수평원관 주위의 상변화 열전달 문제를 예로 들어, 상변화 물질이 유한한 열전도율을 갖는 일정 두께의 원관 주위에 존재할 때의 상변화 문제에 대하여 초기 액상의 영역을 임의로 가정하는 불합리점을 제거하고 문제를 풀 수 있는 수치해석 방법을 제시하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.6
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• pp.966-975
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• 1986

유한한 열전도율과 두께를 갖는 수평동심원관 내의 층류자연대류 문제를 유한차분법을 사용하여 수치적으로 연구하였다. 동심원관 내에는 전도-대류가 복합되어, 전체-유체 경계면에서의 온도분포는 미리 알려져 있지 않다. Prandtl수를 0.7, L/D$_{i}$ = 0.8로 고정하고 각각의 Rayleigh수와 열전도계수의 비, 기하학적변수에 대하여 계산을 수행하였으며, 그 결과를 등온 수평동심원관의 경우와 비교하였다. Rayleigh수와 t/D$_{i}$가 클수록, 열전도계수의 비 K가 작을수록 열저도 효과는 강하게 나타났으며, 국소등가전도계수와 온도분포에 비하여 속도분포는 영향을 덜 받는다는 것이 밝혀졌다.