Bioactive Compounds Extracted from Gamtae (Ecklonia cava) by Using Enzymatic Hydrolysis, a Potent α-Glucosidase and α-Amylase Inhibitor, Alleviates Postprandial Hyperglycemia in Diabetic Mice

이승홍,박미화,한지숙,정윤화,김미숙,전유진 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.4

This study was designed to investigate whether the brown alga gamtae (Ecklonia cava) may inhibit α-glucosidase and α-amylase activities, and alleviate postprandial hyperglycemia in streptozotocin-induced diabetic mice. For that purpose, we prepared an enzymatic hydrolysate from gamtae (EHG) by using the carbohydrase, Celluclast. EHG evidenced prominent inhibitory effect against α-glucosidase and α-amylase. The IC50 values of EHG against α-glucosidase and α-amylase were 0.62 and 0.59mg/mL, respectively, which evidenced the higher activities than that of acarbose. EHG did not exert any cytotoxic effect in human umbilical vein endothelial cells (HUVECs)at various concentrations (from 0.25 to 2 mg/mL). The increase of postprandial blood glucose levels were significantly suppressed in the EHG administered group than those in the streptozotocin-induced diabetic or normal mice. Moreover, the area under curve (AUC) was significantly reduced via EHG administration (6,102 vs. 10,425 mg·min/dL) in the diabetic mice as well as it delays absorption of dietary carbohydrates. These result indicated that EHG might be a potent inhibitor for α-glucosidase and α-amylase.

공동체를 파괴하는 감염공포의 전염, 재난정신건강에 대한 측면

이승홍 연구공동체 건강과대안 2015 의료와사회 Vol.- No.1

Antioxidant and Anti-inflammatory Activities of the Ethanolic Extract of Fermented Red Ginseng Marc

이승홍,오미래,박재현,장세영,정선희,이형일,문상호 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.2

Red ginseng marc (RGM) is generally discarded as waste, even though it contains bioactive components. Hence, this study aimed to evaluate the bioactive components and properties of RGM extracts prepared via the fermentation of Bacillus subtilis (BSRGM) and Saccharomyces cerevisiae (SCRGM). Polyphenols were not detected in non-fermented RGM (NRGM) extracts, whereas the polyphenol levels in RGM extracts significantly increased with fermentation. The BSRGM and SCRGM extracts showed significantly higher free radicals scavenging activity than those of NRGM extracts. Treatment with the fermented RGM extracts also increased IgA levels compared to that of NRGM extracts, whereas it decreased IgE production by the mesenteric lymph node, spleen, and Peyer’s patch lymphocytes. These results suggest that fermented RGM extracts may ameliorate inflammation. In addition, the phenolic compounds in fermented RGM extracts may have biological activity, making fermented RGM extracts a potential natural resource that could be used in the functional foods industry.

원형 실린더 주위의 공기로 국소 대류 열전달에 대한 열전도의 영향

이승홍,이억수 대한설비공학회 1998 설비공학 논문집 Vol.10 No.4

This paper considers the influence of circumferential wall heat conduction for the case of forced convection around a circular cylinder in cross flow of air. Keeping uniform heat generation from the inner surface of the cylinder in radial direction, heat is transferred by wall conduction in the circumferential direction due to the asymmetric nature of the temperature distribution of the cylinder and by convection around the perimeter of the cylinder. The wall conduction depends on conductivity of the cylinder and size of the cylinder radius and thickness and affects the local convective heat transfer rate significantly for geometrically similar surfaces and flow conditions. A nondimensional conjugation parameter K. (=k$_t$R/k$_w$b) has been used to characterize the effect of the circumferntial wall heat conduction. The small values of conjugation parameter K are found to be associated with large effect of wall conduction on the local convective heat transfer rate.

‘전공의 특별법’ 통과, 한국 의료체계를 변화시킬 지렛대가 될 것인가

이승홍 연구공동체 건강과대안 2016 의료와사회 Vol.- No.3

Potential use of ultrasound in antioxidant extraction from Ecklonia cava

이승홍,강민철,문상호,전병태,전유진 한국조류학회I 2013 ALGAE Vol.28 No.4

Water and methanolic extracts of Ecklonia cava, a marine brown alga, were prepared by ultrasonic extraction (UE) and conventional extraction (CE) methods. The radical-scavenging activity and the inhibitory effects against hydrogen peroxide (H2O2)-induced DNA damage of the extracts were investigated. All extracts prepared by CE exhibited higher total polyphenolic content than that in the extracts prepared by UE. Extraction yield and total phenolic content increased as the UE time increased. The radical-scavenging activities increased as the UE time increased. All extracts prepared by CE exhibited higher 1,1-diphenyl-2-pricrylhydrazyl (DPPH) and hydroxyl radical-scavenging activities than did those prepared by UE. Extracts prepared by UE showed stronger scavenging activities on alkyl radical and H2O2 than those prepared by CE did. Methanolic extract with UE 12 h (100MEU-12h) and methanolic extract with CE 24 h (100MEC-24h) were selected and evaluated by comet assay for their inhibitory effect against H2O2-induced DNA damage. 100MEU-12h showed slightly greater protective effect against H2O2-induced DNA damage than 100MEC-24h. Thus, UE can be effectively used as a seaweed extraction technique, and there is potential for scale-up of the extraction process.

수평 원관의 비등 열전달에서 강제대류의 영향

이승홍,이억수,정은행 대한설비공학회 1998 설비공학 논문집 Vol.10 No.5

This paper presents the results of experiments involving external forced convection on boiling heat transfer from electrically heated horizontal tube to water in cross flow. In these experiments, all of the following primary variables were varied: heat flux, cross flow velocity, pressure and degree of subcooling. Local surface temperatures were measured at nine peripheral positions. Surface temperature distributions are classified into four groups as a function of heat flux. The characteristics of the boiling curve at different velocity, degree of subcooling and pressure are examined.

Potential of Benthic Diatoms Achnanthes longipes, Amphora coffeaeformis and Navicula sp. (Bacillariophyceae) as Antioxidant Sources

이승홍,Rohan Karawita,Abu Affan,Joon-Baek Lee,Ki-Wan Lee,이배진,Dong-Woo Kim,전유진 한국조류학회I 2009 ALGAE Vol.24 No.1

Recently, interest in plant-derived food additives has developed natural antioxidants, in order to alternate synthetic antioxidants with several disadvantages. In the present study, different organic fractions from solvent partitions of 80% methanol extract from Jeju benthic diatoms, Achnanthes longipes, Navicula sp. and Amphora coffeaeformis was assessed for their potential antioxidant effects. Among the solvent fractions tested, n-hexane (80.4%) and 80% methanol extract (76.6%) from A. longipes, chloroform (63.2%) from Navicula sp. and n-hexane (67.4%) from A. coffeaeformis were effective in DPPH free radical scavenging. Fractions of chloroform (53.4%) and n-hexane (53.1%) from A. longipes exhibited higher activities on H2O2 scavenging. Fraction of n-Hexane from A. longipes exhibited the highest hydroxyl radical scavenging activity and NO· scavenging activity (56.5% and 75.6%, respectively). Aqueous residue from A. coffeaeformis (75.6%) showed the highest metal chelating effect. Chloroform and ethyl acetate fraction of all the diatoms exhibited significant antioxidant activities in lipid peroxidation inhibitory activity. In particular, both chloroform and the ethyl acetate fraction from A. longipes and A. coffeaeformis exhibited lipid peroxidation inhibitory activity significantly higher than that of α- tocopherol. These data suggest that the Jeju benthic diatoms tested are rich in hydrophilic and hydrophobic antioxidative compounds with different antioxidative properties that can be applied in food industry.

물-공기 혼합분무에 의한 고온 강판 냉각에 대한 연구 (I)

이승홍,이필종,진성태 대한기계학회 2004 大韓機械學會論文集B Vol.28 No.3

거리노숙인의 만성노숙과 연관된 인구사회학적, 임상적 변인

이승홍,배치운,고효정,정운진,고상현 대한신경정신의학회 2016 신경정신의학 Vol.55 No.4

ObjectivesZZThis exploratory study was designed to estimate the socio-demographic characteristics, course of homelessness, adverse childhood experiences, and prevalence of mental disorders among the street homeless people in Seoul, Korea. In addition, we examined the associations between chronic homelessness and study variables. MethodsZZThe study subjects were 75 homeless people dwelling in the street around Seoul Station. Questionnaires related to socio-demographic data and the course of homelessness were provided to each subject. The subjects’ Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) mental disorder diagnoses were made by using Mini International Neuropsychiatric Interview-Plus interviews. ResultsZZMost subjects exhibited chronic homelessness and the prevalence of DSM-IV mental disorders among the homeless subjects was higher than that among the Korean general population. There was a statistically significant association between chronic homelessness and adverse childhood experiences. Compared to those with no history of childhood adversity, homeless people with a history of childhood adversity had a younger age of first homeless episode and a higher prevalence of DSM-IV major mental disorders. The association between DSM-IV diagnosis and chronic homelessness was not significant, but the group with mental disorders had more prevalent re-housing and homeless recurrent histories. ConclusionZZStreet homeless people were often involved in chronic homelessness. Results of this study suggest that homeless people who were never married and had adverse childhood experiences were more vulnerable to chronic homelessness. In addition, we detected a possible relationship between the recurrence of homelessness and the presence of mental disorders.