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Antioxidant Constituents from Leonurus japonicus
Guan-Zheng Qu,Chuan-Ling Si,왕명현 한국생약학회 2006 Natural Product Sciences Vol.12 No.4
phenolic acids, gallic acid (1) and syringic acid (2), and five flavonoids, apigenin (3), luteolin (4),kaempferol (5), quercetin (6), and myricetin (7), were isolated from the aerial parts of Leonurus japonicus. Theirstructures were elucidated by chemical and spectral analysis. The antioxidant activities of the crude extracts,partitioned fractions and isolated compounds were evaluated by DDPH fre radical-scavenging assay. Resultssuggested that the EtOAc partitioned fraction and compounds 1, 4, 5, 6, and 7 showed significantly highα-tocopherol and BHT, which were used as controls.KeywordsAerial parts, antioxidant, constituents, Leonurus japonicus
Chemical Composition and Active Antioxidants of Eucommia ulmoides Oliv. Bark
Guan-Zheng Qu,Chuan-Ling Si,Yu Yin,Myeong-Hyeon Wang 한국영양학회 2006 Nutritional Sciences Vol.9 No.4
??Chemical composition of the Eucommia ulmoides bark, including extractives, proximate, mineral, fatty acid and monosaccharide compositions, was studied The most abundant mineral was calcium (533.17 ㎎/100 g). α-linolenic acid (24.7%) and linoleic acid (24.3%), showed higher contents among the fatty acids. Major monosaccharides of E. ulmoides bark were arabinose (13.94 ㎎/g), xylose (18.91 ㎎/g) and glucose (119.7 ㎎/g). From the bark of E. ulmoides, four compounds were isolated and their structures were elucidated as caffeic acid (Ⅰ), kaempferol (Ⅱ), quercetin (Ⅲ) and isoquercitrin (Ⅳ) by spectroscopic analysis such as NMR and MS, including cellulose TLC and other chemical evidence such as hydrolyzation and acetylation. The antioxidant activities of four isolated compounds were evaluated by DPPH free radical scavenging, hydroxyl scavenging and reducing power assays. The results indicated that all the isolated compounds showed higher DPPH radical scavenging activity than α-tocopherol and BHT that were used as positive controls and these four compounds exhibited considerable reducing power and hydroxyl radical (OH') scavenging activity. Considering from the results above, it suggests that the E. ulmoides bark is a potential natural source of antioxidant material.
Antioxidant and Antidiabetic Activities of Eucommia ulmoides Bark
Qu, Guan-Zheng,Heo, Seong-Il,Wang, Myeong-Hyeon The Korean Society for Applied Biological Chemistr 2006 Journal of Applied Biological Chemistry (J. Appl. Vol.49 No.3
Eucommia ulmoides bark extracts by cold water, boiling water, 100% EtOH, 70% EtOH, 100% MeOH, 70% MeOH and $CHCl_3$ were assayed for their medicinal effects. The antioxidant activity of the extracts ranged from $IC_{50}$ 125.2 to $IC_{50}\;872.7{\mu}g/ml$ in the 1,1-diphenyl-2-picrylhydrazyl (DDPH) free radical-scavenging assay, and cold water extracts had the highest antioxidant activity. $CHCl_3$ extracts had the highest inhibitory effect on angiotensin I-converting enzyme (ACE) giving inhibition of up to 56.4% at a concentration of 1 mg/ml. Extracts in 100% EtOH had the greatest inhibitory effect on $\acute{a}-amylase$ activity ($IC_{50}=174.6{\mu}g/ml$), and 70% MeOH extracts had the greatest inhibitory effect on ${\alpha}-glucosidase$ activity ($IC_{50}=14.0{\mu}g/ml$). Taken together, these results provided the in vitro evidence on the ACE, amylase and glucosidase inhibitory actions of E. ulmoides bark that form the pharmacological basis for its antihypertensive and antidiabetic action.
Antioxidant, Antidiabetic and Cytotoxic Effects of Eucommia ulmoides Oliv. Bark in vitro
Qu, Guan-Zheng,Lee, Sung-Hyun,Wang, Myeong-Hyeon The Korean Society for Applied Biological Chemistr 2006 Journal of Applied Biological Chemistry (J. Appl. Vol.49 No.4
The aim of this study is to investigate in vitro biological properties of Eucommia ulmoides Oliv. bark. Ethyl acetate(EtOAc) fraction from aqueous extract of Eucommia bark showed strong antioxidant activity of $IC_{50}$ 19.2 ${\mu}g/ml$ by 1,1-diphenyl-2-picrylhydrazyl(DPPH) free radical-scavenging assay. The Eucommia bark extract showed $\alpha$-glucosidase inhibitory activity and inhibited growth of human liver cancer cell, suggesting its potential biological value of anticancer.
High Precision FE Modeling for Predicting Inner Polygon Defect of Hot Rolled Seamless Steel Tubes
Yong-Zheng Jiang,Yong-Zheng Jiang,Xiao-Ping Zhang,Kuan-Fang He,Guan-Fu Bin 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.11
A high precision FE model is the key basis for cause analysis and overcoming of inner polygon defect of hot rolled seamless steel tubes. In this paper, the viscoelastic-plastic FEM is adopted in order to develop a high precision FE model for predicting the defect of inner polygon. Mechanical properties of tube material under rolling environment is obtained through five sets of high temperature compression tests, thus the viscoelastic-plastic constitutive equation of tube material is regressed and agrees with the tests results. Heat transfer boundary conditions, roll constant speed and contact friction boundary conditions are applied simultaneously on the FE model and thermo-mechanical coupled explicit algorithm is adopted for solution. The precision of the FE model is verified through industry experiments. Results shows the simulated inner wall shape is in good accordance with the experiment results, and the friction force, stress, strain and temperature distribution in the deformation zone are also discussed. It can be concluded that the viscoelastic-plastic FE model is of high precision and can be applied for better analysis of the hot rolling results.
Zheng Lin Zhao,Guang Wen Zhao,Li Li,Meng Quan Li,Li Xin Guan,Xu Dong Yang,Hou Zhong Li,Feng Lin,Jong Rok Lee,Rong Jie Zhao 한국독성학회 2009 Toxicological Research Vol.25 No.1
The effects of aqueous extract of Schizandra Chinensis Fruit (AESC) on cadmium-induced changes of monoamine neurotransmitters in the different brain regions of adult rats were investigated. Male rats were received intraperitoneal (i.p.) administration of CdCl₂ (0.6 ㎎/㎏/d) for 21 days and sacrificed 7 days after the last administration. Concentrations of norepinephrine (NE), dopamine (DA) in striatum and serotonin (5-HT), 5-hydroxyindole acetic acid (5-HIAA) in cortex were measured by HPLC. There were significant decreases of NE, DA, 5-HT and 5-HIAA in Cd intoxicated rats (P < 0.05), while pretreatment with AESC (20 ㎎/㎏/d or 60 mg/kg/d, p.o., 30 min before CdCl₂) greatly inhibited the decrease of monoamine transmitters, respectively (P < 0.05). Also, AESC significantly increased the reduction of glutathione contents and superoxide dismutase activities in cortex induced by CdCl₂. These results suggest that AESC ameliorates Cd-induced depletion of monoamine neurotransmitters in brain through its antioxidant activity.
Zheng, Pan-deng,Guo, Zi-xiong,Hou, Wei,Lin, Guan Techno-Press 2021 Advances in concrete construction Vol.11 No.3
Extensive research has been conducted on the basic mechanical property and structural applications of engineered cementitious composites (ECC). Despite the high tensile ductility and high toughness of ECC, transverse steel reinforcement is still necessary to confine ECC for high performance. However, limited research has examined performance of ECC confined with practical amount of transverse reinforcement. This paper presents the results of axial compression tests on 14 square ECC columns and 4 conventional concrete columns (used as control specimens) with transverse reinforcement. The test variables were spacing, configuration (square ties or square and diamond shape ties), and yield strength of stirrups. The test showed that ECC columns confined with steel stirrup had good compressive ductility, and the stirrup spacing had the greatest effect on the compressive performance. The self-confinement effect of ECC results in a more uniform but slower expansion of the whole column compared with CC ones. The test results are then compared against the predictions from a number of existing models for conventional confined concrete. It is indicated that these models fail to predict the axial strains at peak axial stress and the trend of the stress-strain curve of steel stirrups-confined ECC with sufficient accuracy. Several new equations are then proposed for the compressive properties of steel-confined ECC based on test results and potential approaches for future studies are proposed.