• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.3
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• pp.233-244
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• 2008

In this study, the antioxidative effects, inhibitory effects on elastase and tyrosinase, and component analysis of Psidium guajava leaf extracts were investigated. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activities $(FSC_{50})$ of extract/fractions of Psidium guajava leaf were in the order: 50% ethanol extract $(7.05{\mu}g/mL)$ < ethyl acetate fraction $(3.36{\mu}g/mL)$ < deglycosylated flavonoid aglycone fraction $(3.24{\mu}g/mL)$. Reactive oxygen species (ROS) scavenging activities $(OSC_{50})$ of some Psidium guajava leaf extracts on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using the luminol-dependent chemiluminescence assay. The order of ROS scavenging activities were 50% ethanol extract $(OSC_{50},\;2.17{\mu}g/mL)$ < ethyl acetate fraction $(0.64{\mu}g/mL)$ < deglycosylated flavonoid aglycone fraction $(3.39{\mu}g/mL)$. Aglycone fraction showed the most prominent ROS scavenging activity. The protective effects of extract/fractions of Psidium guajava leaf on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The Psidium guajava leaf extracts suppressed photohemolysis in a concentration dependent manner $(1{\sim}10{\mu}g/mL)$, particularly deglycosylated flavonoid aglycone fraction exhibited the most prominent celluar protective effect ${\tau}_{50}\;107.5min\;at\;1{\mu}g/mL)$. Aglycone fraction obtained from the deglycosylation reaction of ethyl acetate fraction among the Psidium guajava leaf extracts, showed 1 band in TLC and 1 peak in HPLC experiments (360 nm). One component was identified as quercetin. TLC chromatogram of ethyl acetate fraction of Psidium guajava leaf extract revealed 5 bands and HPLC chromatogram showed 5 peaks, which were identified as quercetin 3-O-gentobioside (10.32%) , quercetin 3-O-${\beta}$-D-glucoside (isoquercitin, 13.30%), quercetin 3-O-${\beta}$-D-galactoside (hyperin, 11.34%), quercetin 3-O-${\alpha}$-L-arabinoside (guajavarin, 19.70%), quercetin 3-O-${\beta}$-L-rhamnoside (quercitrin, 45.33%) in the order of elution time. The inhibitory effect of Psidium guajava leaf extracts on tyrosinase were investigated to assess their whitening efficacy. Finally, their anti-elastase activities were measured to predict the anti-wrinkle efficacy in the human skin. Inhibitory effects $(IC_{50})$ on tyrosinase of some Psidium guajava leaf extracts was 50% ethanol extract $(149.67{\mu}g/mL)$ < ethylacetate fraction $(30.67{\mu}g/mL)$ < deglycosylated aglycone fraction $(17.10{\mu}g/mL)$. Inhibitory effects $(IC_{50})$ on elastase of some Psidium guajava leaf extracts was 50% ethanol extract $(6.60{\mu}g/mL)$ < deglycosylated aglycone fraction $(5.66{\mu}g/mL)$ < ethylacetate fraction $(3.44{\mu}g/mL)$. These results indicate that extract/fractions of Psidium guajava leaf can function as antioxidants in bioloigcal systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. And component analysis of Psidium guajava leaf extract and inhibitory activity on elastase of the aglycone fraction could be applicable to new functional cosmetics for smoothing wrinkles.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.455-462
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• 2000

The objective of this study was to examine the physicochemical characteristics of coagulation reaction between loess and red tide organisms (RTO) and its feasibility, in developing a technology for the removal of RTO bloom in coastal sea. The physicochemical characteristics of loess were examined for a particle size distribution, surface characteristics by scanning electron microscope, zeta potential, and alkalinity and pH variations in sea water. Two kinds of RTO that were used in this study, Cylindrothen closterium and Skeietonema costatum, were sampled in Masan bay and were cultured in laboratory. Coagulation experiments were conducted using various concentrations of loess, RTO, and a jar tester. The supernatant and RTO culture solution were analyzed for pH, alkalinity, RTO cell number. A negative zeta potential of loess increased with increasing pH at $10^(-3)M$ NaCl solution and had -71.3 mV at pH 9.36. Loess had a positive zeta potential of +1,8 mV at pH 1.98, which resulted in a characteristic of material having an amphoteric surface charge. In NaCl and $CaCl_2$, solutions, loess had a decreasing negative zeta potential with increasing $Na^+\;and\;Ca^(+2)$ ion concentration and then didn't result in a charge reversal due to not occurring specific adsorption for $Na^+$ ion while resulted in a charge reversal due to occurring specific adsorption for $Ca^(+2)$ ion. In sea water, loess and RTO showed the similar zeta potential values of -112,1 and -9.2 mV, respectively and sea sand powder showed the highest zeta potential value of -25.7 mV in the clays. EDLs (electrical double-layers) of loess and RTO were extremely compressed due to high concentration of salts included in sea water, As a result, there didn't almost exist EDL repulsive force between loess and RTO approaching each other and then LVDW (London-yan der Waals) attractive force was always larger than EDL repulsive force to easily form a floe. Removal rates of RTO exponentially increased with increasing a loess concentration. The removal rates steeply increased until $800 mg/l$ of loess, and reached $100{\%}$ at 6,400 mg/l of loess. Removal rates of RTO exponentially increased with increasing a G-value. This indicated that mixing (i.e., collision among particles) was very important for a coagulation reaction. Loess showed the highest RTO removal rates in the clays.

• Journal of Life Science
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• v.19 no.5
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• pp.652-658
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• 2009

The comparative activities of aqueous, ethanol, and methanol extracts from Aralia elata shoot (AES) and leaf (AEL) were tested by in vitro experimental models of linoleic acid peroxidation by thiocyanate and thiobarbituric acid (TBA) methods and scavenging activities of free radicals by DPPH (${\alpha}$,${\alpha}$'-diphenyl-${\beta}$-picrylhydrazyl). In addition, bio-active materials (phenolic compounds and minerals) were also measured. The extract yield of each solvent extracted from AES and AEL was 3.08% and 3.13% in aqueous, 0.58% and 0.66% in ethanol, and 0.81% and 1.73% in methanol, respectively. The highest extract yield was found in the aqueous extract from AEL. Major mineral contents (mg%) of AES and AEL were 575.7 and 759.3 in Ca, 353.5 and 330.0 in K, and 31.3 and 31.0 in Mg, respectively. The highest free radical scavenging activity was found in the aqueous extract by 28.69% at 0.1% additional level from AES and in the methanol extract by 92.36% at 0.1% additional level from AEL. Free radical scavenging activity was stronger in AEL than in AES. In antioxidative activities determined by thiocyanate and TBA methods against lipid peroxidation using linoleic acid, ethanol extracts from AEL showed the highest antioxidative activity at all treatment concentrations. These results may provide the basic data to understand the biological activities of bio-active materials derived from AES and AEL.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.418-429
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• 2011

Novel chromium(III), manganese(II), iron(III), cobalt(II), nickel(II), copper(II), ruthenium(III), and zirconyl(II) complexes of $N^1,N^2$-bis(3-((3-hydroxynaphthalen-2-yl)methylene-amino)propyl)phthalamide ($H_4L$, 1) have been synthesized and characterized by elemental, physical, and spectral analyses. The spectral data showed that the ligand behaves as either neutral tridentate ligand as in complexes 2-5 with the general formula $[H_4LMX_2(H_2O)]{\cdot}nH_2O$ (M=Cu(II), Ni(II), Co(II), X = Cl or $NO_3$), neutral hexadentate ligand as in complexes 10-12 with the general formula $[H_4LM_2Cl_6]{\cdot}nH_2O$ (M=Fe(III), Cr(III) or Ru(III)), or dibasic hexadentate ligand as in complexes 6-9 with the general formula $[H_2LM_2Cl_2(H_2O)_4]{\cdot}nH_2O$ (M = Cu(II), Ni(II), Co(II) or Mn(II), and 13 with general formula $[H_4L(ZrO)_2Cl_2]{\cdot}8H_2O$. Molar conductance in DMF solution indicated the non-ionic nature of the complexes. The ESR spectra of solid copper(II) complexes 2, 5, and 6 showed $g_{\parallel}$ >g> $g_e$, indicating distorted octahedral structure and the presence of the unpaired electron in the $N^1,N^2$ orbital with significant covalent bond character. For the dimeric copper(II) complex $[H_2LCu_2Cl_2(H_2O)_4]{\cdot}3H_2O$ (6), the distance between the two copper centers was calculated using field zero splitting parameter for the parallel component that was estimated from the ESR spectrum. The antibacterial and antifungal activities of the compounds showed that, some of metal complexes exhibited a greater inhibitory effect than standard drug as tetracycline (bacteria) and Amphotricene B (fungi).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.6
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• pp.253-257
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• 2008

To enhance the luminescence properties, the red phosphor composed of $(Y,\;Zn)_2O_3$:$Eu^{3+}$ as doping concentration of Zn ion is synthesized at $1200^{\circ}C$ for 6 hrs in air atmosphere by conventional solid reaction method. As a result of the red phosphor $(Y,\;Zn)_2O_3$:$Eu^{3+}$ is measured X-ray diffraction (XRD), The main peak is nearly corresponded to the same as JCPDS card (No. 41-1105). When the doping concentration of Zn ion is more than 5 mol%, However, the ZnO peak is showed by XRD analysis. Therefore, when the doping concentration of Zn ion is less than 5 mol%, the Zn ion is well mixed in $Y_2O_3$ structure without the impurity phases. The photoluminescence (PL) properties is shown as this phosphor is excited in 254 nm region and the highest emission spectra of $(Y,\;Zn)_2O_3$:$Eu^{3+}$ has shown in 612 nm region because of a typical energy transition ($^5D_0{\rightarrow}^7F_2$) of $Eu^{3+}$ ion. As the doping concentration of Zn ion is more than 10 mol%, the emission peak is suddenly decreased. when the highest emission peak as doping concentration of Zn ion is shown, the composition of this phosphor is $(Y_{0.95},\;Zn_{0.05})_2O_3$:$Eu^{3+}_{0.075}$ and the particle size analyzed by FE-SEM is confirmed from 0.4 to $3{\mu}m$.

• Applied Microscopy
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• v.30 no.4
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• pp.347-355
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• 2000

Zinc is one of the most abundant oligoelements in the living cell. It appears tightly bound to some metalloproteins and nucleic acids, loosely bound to some metallothioneins or even as free ion. Small amounts of zinc ions (in the nanomolar range) regulate a plentitude of enzymatic proteins, receptors and transcription factors, thus rolls need accurate homeostasis of zinc ions. Zinc is an essential catalytic or structural element of many proteins, and a signaling messenger that is released by neural activity at many central excitatory synapses. Growing evidences suggest that zinc may also be a key mediator and modulator of the neuronal death associated with transient global ischemia and sustained seizures, as well as perhaps other neurological disease stoles. Some neurons have developed mechanisms to accumulate zinc in specific membrane compartment ('vesicular zinc') which can be evidenced using histochemical techniques. Substances giving a bright colour or emitting fluorescence when in contact with divalent metal ions are currently used to detect them inside cells; their use leads to the so called 'direct' methods. The fixation and precipitation of metal ions as insoluble salt precipitates, their maintenance along the histological process and, finally, their demonstration after autometallographic development are essential steps for other methods, the so called 'indirect methods'. This study is a short report on the autometallograhical approaches for zinc detection in the central nervous system (CNS) by means of a modified selenium method.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.69-80
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• 1998

This research was designed to investigate how the exercise program affects paraplegic standing and walking employing functional electrical stimulation(FES). Emphasis was also given to fatigue of major lower extremity muscles induced by different types of electrical stimulation. We applied continuous and intermittent rectangular pulse trains to quadriceps of 10 normal subjects and 4 complete paraplegic patients. The frequencies were 20Hz and 80Hz, and the knee angle was fixed at 90$^{\circ}$and 150$^{\circ}$to investigate how muscle fatigue is related to muscle length. The knee extensor torque was measured and monitored. We have been training quadriceps and gastrocnemius of a male paraplegic patient by means of electrical stimulation for the past two year. FES standing was initiated when the knee extensors became strong enough to support the body weight, and then the patient started FES walking utilizing parallel bars and a walker. We used an 8-channel constant-voltage stimulator and surface electrodes. The experimental results indicated that paralyzed muscles fatigued rapidly around the optimal length contrary to normal muscles and confirmed that low frequency and intermittent stimulation delayed fatigue. Our exercise program increased muscle force by approximately 10 folds and decreased the fatigue index to half of the initial value. In addition, the exercise enabled the patient to voluntarily lift each leg up to 10cm, which was of great help to the swing phase of FES walking. Both muscle force and resistance to fatigue were significantly enhanced right after the exercise was applied every day instead of 6 days a week. Up to date, the patient can walk for more than two and half minutes at 10m/min while controlling the on/off time of the stimulator by pushing the toggle switch attached to the walker handle.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.121-135
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• 2012

Soil dispersion and heavy metal leaching with two heavy metal-contaminated soils were studied to derive the optimal dispersion condition in the course of developing the remedial technology using magnetic separation. The dispersion solutions of pyrophosphate, hexametaphosphate, orthophosphate and sodium dodecylsulfate (SDS) at 1 - 200 mM and the pH of solutions was adjusted to be 9 - 12 with NaOH. The clay content of suspension as an indicator of dispersion rate and the heavy metal concentration of the solution were tested at the different pHs and concentrations of the dispersion solution during the experiment. The dispersion rate increased with increasing the pH and dispersion agent concentration of the solution. The dispersion efficiency of the agents showed as follows: pyrophosphate > hexametaphosphate > SDS > orthophosphate. Arsenic leaching was sharply increased at 50 mM of phosphates and 100 mM of SDS. The adsorption of $OH^-$, phosphates and dodecysulfate on the surface of Fe- and Mn-oxides and soil organic matter and the broken edge of clay mineral might decrease the surface charge and might increase the repulsion force among soil particles. The competition between arsenic and $OH^-$, phosphates and dodecylsulfate for the adsorption site of soil particles might induce the arsenic leaching. The dispersion and heavy metal leaching data indicate that pH 11 and 10 mM pyrophosphate is the optimum dispersion solution for maximizing dispersion and minimizing heavy metal leaching.

• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.479-484
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• 2017

In this study, antioxidative activities and cellular protective effects of 70% ethanol extracts and fractions from lavender were evaluated. The scavenging activity ($FSC_{50}$) of free radical (1,1-phenyl-2-picrylhydrazyl, DPPH) was 46.6, 45.5 and $477.5{\mu}g/mL$ in the 70% ethanol extract, ethyl acetate fraction and aglycone fraction, respectively. The reactive oxygen species scavenging activities (${OSC_{50}$) of 70% ethanol extract, ethyl acetate fraction and aglycone fraction were 8.1, 3.3 and $17.6{\mu}g/mL$, respectively, and they showed lower antioxidative activity than that of using L-ascorbic acid ($1.5{\mu}g/mL$). However, the aglycone fraction showed higher photohemolysis protective effect than that of using the 70% ethanol extract and ethyl acetate fraction. At $50{\mu}M$ concentration, the cellular protective effect (${\tau}_{50}$) of 70% ethanol extract, ethyl acetate fraction and aglycone fraction from lavender was 70.6, 87.2 and 165.2 min, respectively. In particular, the lavender aglycone fraction showed 3.8 times higher cellular protective effect than that of (+)-${\alpha}$-tocopherol. The lavender fractional components including luteolin 7-O-glucuronide, vitextin, rosmarinic acid, luteolin, and apigenin were identified using TLC and LC-MS. However, the lavender aglycone fraction did not show any significant increase in flavonoids (luteolin and apigenin) compared to that of the ethyl acetate fraction. In conclusion, it is suggested that lavender may be applied as an antioxidant material in cosmetic industries.

• Journal of Life Science
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• v.18 no.10
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• pp.1377-1383
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• 2008

A bacterium producing non- or partially digestible dextran was isolated from kimchi broth by enrichment culture technique. The bacterium was identified tentatively as Leuconostoc sp. strain SKY. We established the response surface methodology (Box-Behnken design) to optimize the principle parameters such as culture pH, temperature, and yeast extract concentration for maximizing production of dextran. The ranges of parameters were determined based on prior screening works done at our laboratory and accordingly chosen as 5.5, 6.5, and 7.5 for pH, 25, 30, and $35^{\circ}C$ for temperature, and 1, 5, and 9 g/l yeast extract. Initial concentration of sucrose was 100 g/l. The mineral medium consisted of 3.0 g $KH_2PO_4$, 0.01 g $FeSO_4{\cdot}H_2O$, 0.01 g $MnSO_4{\cdot}4H_2O$, 0.2 g $MgSO_4{\cdot}7H_2O$, 0.01 g NaCl, and 0.05 g $CaCO_3$ per 1 liter deionized water. The optimum values of pH and temperature, and yeast extract concentration were obtained at pH (around 7.0), temperature (27 to $28^{\circ}C$), and yeast extract (6 to 7 g/l). The best dextran yield was 60% (dextran/g sucrose). The best dextran productivity was 0.8 g/h-l.