소사나무(Carpinus turczaninowii, C. turczaninowii) 잎 추출물의 멜라닌 생성 억제활성을 B16F10 melanoma 세포를 이용하여 측정하였다. 그 결과, 에탄올 추출물($100{\mu}g/mL$)에서 72.2%의 생성 억제 효과를 확인하였으며, 동일 농도에서 MTT 세포독성은 거의 나타나지 않았다. 분획물(헥산, 에틸아세테이트, 부탄올 및 물)을 제조한 후 실험을 진행한 결과, 에틸아세테이트 분획에서 가장 우수한 활성이 관찰되었다. 에틸아세테이트 분획에서 활성성분을 규명하기 위하여 크로마토그라피를 진행하였으며, 4개의 화합물을 분리 동정하였다; ethyl gallate (1), quercetin rhamnose (2), kaempferol rhamnose (3), quercetin galloylrhamnose (4). 화합물의 구조규명은 핵자기공명분광기 등을 이용하여 이루어졌으며, 4개의 화합물 모두 소사나무 잎에서는 처음 분리된 물질이다. 분리된 화합물을 대상으로 멜라닌 생성 억제활성 실험을 진행한 결과, 화합물 4에서 세포독성 없이 농도의존적인 억제활성을 확인하였다. 또한, 화합물 4는 세포 내에서 티로시나제 발현양을 감소시키고 있음을 ELISA를 통하여 확인하였다. 이상의 결과를 바탕으로, 소사나무 잎 추출물이 화장품에서 미백제로 활용될 가능성이 있다고 판단된다. Melanin synthesis inhibition activities were investigated for the extracts prepared from the leaves of Carpinus turczaninowii (C. turczaninowii) by using B16F10 melanoma cells. As a result, the ethanol extract ($100{\mu}g/mL$) showed 72.2% inhibition activities without cell toxicities in MTT assays. For the solvent fractions (n-hexane, ethyl acetate, n-butanol, water), the most potent activities were observed at the ethyl acetate fraction. To isolate the active constituents, the ethyl acetate fraction was further purified to afford four compounds; ethyl gallate (1), quercetin rhamnose (2), kaempferol rhamnose (3) and quercetin galloylrhamnose (4). The identification of the isolates was made by spectroscopic data including NMR spectra, and all of the compounds 1-4 were isolated for the first time from the leaves of C. turczaninowii. Anti-melanogenesis activities were studied for the isolates 1-4, and the compound 4 was determined to decrease the melanin synthesis dose-dependently without causing cell toxicities. ELISA measurement indicated that the isolate 4 decreased the contents of cell tyrosinase, a critical enzyme in melanogenesis. Based on these results, the extracts of C. turczaninowii were found to be applicable as whitening ingredients in cosmetic formulations.
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On Jeju Island, South Korea, the leaves of Eurya emarginata have been traditionally used to treat ulcers or as a diuretic. Eutigoside C isolated from the leaves has been reported to have in vitro anti-inflammatory effects. We evaluated the radioprotective effects of eutigoside C on jejunal cell apoptosis and crypt survival in mice subjected to gamma irradiation. In addition, the ability of eutigoside C to protect against radiation-induced oxidative stress was examined by evaluating the activities of superoxide dismutase (SOD) and catalase (CAT) in radiation-induced hepatic injury. Eutigoside C was administered intraperitoneally at 48, 12, and 1 h before irradiation. The administration of eutigoside C (10, 50, or 100 mg/kg body weight) before irradiation protected the intestinal crypts from radiation-induced apoptosis (p < 0.05), and attenuated radiation-induced decrease of villous height (p < 0.05). Pretreating mice prior to irradiation with eutigoside C (100 mg/kg) significantly improved the survival of the jejunal crypt (p < 0.01). The dose reduction factor was 1.09 at 3.5 days after irradiation. Treatment of eutigoside C prior to irradiation significantly protected SOD and CAT activities in radiation-induced hepatic injury (p < 0.05). These results suggest that eutigoside C is a useful radioprotector capable of defending intestinal progenitor cells against indirect depletion, such as oxidative stress and inflammatory response caused by gamma irradiation.
Toxicity of particulate matter (PM) towards the epidermis has been well established in many epidemiological studies. It is manifested in cancer, aging, and skin damage. In this study, we aimed to show the mechanism underlying the protective effects of eckol, a phlorotannin isolated from brown seaweed, on human HaCaT keratinocytes against PM2.5-induced cell damage. First, to elucidate the underlying mechanism of toxicity of PM2.5, we checked the reactive oxygen species (ROS) level, which contributed significantly to cell damage. Experimental data indicate that excessive ROS caused damage to lipids, proteins, and DNA and induced mitochondrial dysfunction. Furthermore, eckol (30 μM) decreased ROS generation, ensuring the stability of molecules, and maintaining a steady mitochondrial state. The western blot analysis showed that PM2.5 promoted apoptosis-related protein levels and activated MAPK signaling pathway, whereas eckol protected cells from apoptosis by inhibiting MAPK signaling pathway. This was further reinforced by detailed investigations using MAPK inhibitors. Thus, our results demonstrated that inhibition of PM2.5-induced cell apoptosis by eckol was through MAPK signaling pathway. In conclusion, eckol could protect skin HaCaT cells from PM2.5-induced apoptosis via inhibiting ROS generation.
The aim of this study was to investigate the in vitro inhibitory effects of acanthoic acid (ACAN), isolated from Acanthopanax koreanum, on melanogenesis and its related enzymes such as tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 in B16 melanoma cells. We found that ACAN significantly attenuates melanin synthesis and reduces the activity of intracellular tyrosinase, the rate-limiting melanogenic enzyme. Western blot analysis showed that ACAN also decreases tyrosinase, TRP-1, and TRP-2 protein expression. In addition, ACAN significantly decreased the expression of microphthalmia-associated transcription factor (MITF), a key regulator of melanogenesis. These results indicate that ACAN effectively inhibits melanin biosynthesis through down-regulation of MITF and thus could be useful as a new skin-whitening agent.
This study was conducted to identify the antimelanogenic components from Raphanus sativus L. var. niger (black radish). Phytochemical study with the ethanol extract of black radish roots resulted in the isolation of six compounds: 3‐( E )‐(methylthio)methylene‐2‐pyrrolidinethione ( 1 ), ascorbigen ( 2 ), β‐sitosterol ( 3 ), palmitic acid ( 4 ), α‐linolenic acid ( 5 ), and 1‐linoleonyl glycerol ( 6 ). Among the isolates, the thione 1 efficiently inhibited melanin synthesis in a concentration‐dependent manner in α‐MSH stimulated B16F10 melanoma cells. Western blotting analysis for the key melanogenic enzymes showed that compound 1 decreased tyrosinase and tyrosinase‐related protein‐2 expressions. These results demonstrated that the black radish extract including pyrrolidinethione 1 could be useful as antimelanogenic agents in cosmetic or pharmaceutical applications.