• Applied Biological Chemistry
• /
• v.37 no.5
• /
• pp.409-413
• /
• 1994

Barbaloin in the Aloe vera depending on the various extracting conditions was analyzed by HPLC. The contents of the barbaloin extracted by the solvents increased in the order of methanol>ethanol>water extraction. In setting extraction, the contents of barbaloin extracted with methanol and ethanol were increased from four hours at $60^{\circ}C$ and then decreased. The contents of barbaloin extracted with water were different depending on the temperature and time. Increasing the extracting time and temperature, the contents of barbaloin were decreased in water extract. It was estimated that the barbaloin might be stable in organic solvent, but decomposed with hydrolysis in water.

• Journal of the Mineralogical Society of Korea
• /
• v.23 no.1
• /
• pp.63-71
• /
• 2010

The artificial rains having different pH and weathering simulation test were performed for Gyeongju Namsan granite and dacitic tuff to predict the role of acid rain in the deterioration of stone monuments located in Gyeongju area. The pH 4.0 rain reacted with the fresh granite showed near neutral pH at the early stage due to the hydrolysis of minerals in the rock surface. But the pH changed back to the initial pH in the later stage. On the other hand, the pH 5.6 rain showed the neutral pH for a longer time than the experiment with pH 4.0 rain, reflecting slower reaction of minerals due to the weaker acidity. When the pH 5.6 rain reacted with the weathered granite, the water showed neutral pH longer than the case of the fresh granite. The similar tendencies were observed in the experiment of dacitic tuff, except that the pH 4.0 rain reacted with dacitic tuff took a longer time to go back to the initial pH as compared with the case of granite. These results may due to the differences in mineral composition and texture of two rocks. Dacitic tuff contains more fine-grained or glassy groundmass than granite and is more reactive with weaker acid rain. It was predicted that the weight loss and strength decrease rate of dacitic tuff would be approximatetly twice relative to those of granite in the same experimental environment.

• Korean Chemical Engineering Research
• /
• v.60 no.3
• /
• pp.414-422
• /
• 2022

The objective of this work was to investigate the feasibility of acid-catalyzed hydrothermal fractionation for maximum solubilization of the hemicellulosic portion of two typical agricultural residues. The fractionation conditions converted into combined reaction severity (CS) in the range of 1.2-2.9 was used to establish a simple reaction criteria at glance. The hemicellulosic sugar yield of 56.6% was shown when rice straw was fractionated at the conditions at the conditions; 160 ℃ of temperature 0.75% (w/v) of H₂SO₄, 20 min of reaction time, 1:15 solid/liquid ratio. The hemicellulosic sugar yield of 83.0%, however, was achieved when barley straw was fractionated at the conditions at the conditions; 150 ℃ of temperature 0.75% (w/v) of H₂SO₄, and 15 min of reaction time, 1:10 solid/liquid ratio. For barley straw, acid-catalyzed hydrothermal fractionation could be effectively performed. After the fractionation process, the remaining fractionated solids were 48.5% and 57.5% from raw rice and barley straws, respectively. The XMG contents in the solid residues decreased from 17.3% and 17.6% to 6.0% and 2.6%, which corresponded to 16.7% and 8.5% on the basis of the raw straws, respectively. In another way, only 5.6% of cellulose and 8.5% of XMG were lost due to excessive decomposition during the acid-catalyzed hydrothermal fractionation of barley straw, compared to cellulose and XMG losses of 6.4% and 26.6% in rice straw. Hemicellulosic sugars from the rice straw were considered more over-decomposed due to the somewhat higher reaction severity at the acid-catalyzed hydrothermal fractionation.

• Korean Chemical Engineering Research
• /
• v.61 no.2
• /
• pp.265-272
• /
• 2023

Lignocellulosic biomass is essential to pretreatment because of having rigid structures and a lot of lignin. Among methods of pretreatment, using THF solvents has the advantage of being easy to reuse. THF (Tetrahydrofuran) used as a co-solvent with water or ionic solvent that is inexpensive and can remove lignin over a wide range of reaction conditions. NaOH (Sodium hydroxide) has been demonstrated to preferentially solvate lignin from cellulose. Thus, NaOH was used as a pretreatment co-solvent for the fractionation of lignin by destroying the ether bond to amend for hydrolysis and expand the surface area of cellulose and hemicellulose. In this experiment, lignin was removed by the NaOH/THF co-solvent pretreatment process to characteristics for the pretreatment and obtain the optimal levulinic acid conversion yield through the acid catalyst conversion process. the NaOH/THF co-solvent system was conducted in various ratios of co-solvent under a total of 16 conditions. And the temperature was 180 ℃ during to 60 mins. The optimum condition of co-solvent is NaOH 5 wt%/THF 90:10(v/v%), 76.8% glucan content was obtained through this co-solvent pretreatment, and 90.1% lignin was removed. In the acid catalyst conversion process, which is a subsequent pretreatment process, the experiment was conducted under the conditions of 30 to 90 min of reaction time and 160 ℃ to 200 ℃ reaction temperature. The optimum condition of acid catalyst conversion process is 60min reaction time under of 180 ℃, and it obtained 84.7% of levulinic aicd conversion yield.

• Journal of Applied Biological Chemistry
• /
• v.61 no.1
• /
• pp.101-108
• /
• 2018

This study was conducted to establish optimized ${\beta}-glucan$ extraction method through enzymatic hydrolysis from Phellinus baumii and investigate ${\beta}-glucan$ contents and physicochemical properties. The optimal condition was obtained with the enzyme concentration of 0.66% (v/v), reaction time of 6.08 h ($R^2=0.9245$) and the ${\beta}-glucan$ contents from the Phellinus baumii extracts under the optimized condition was 1.9594 g/100 g. ${\beta}-Glucan$ yield (0.76-16.40%) of enzyme beta-glucan extract (EBE) was three fold higher than that of non-enzyme beta-glucan extract (NEBE). ${\beta}-Glucan$ purity (11.15-59.05%) of non-enzyme beta-glucan (NEB) and that of enzyme beta-glucan (EB) were higher than that of NEBE and that of EBE. ${\beta}-Glucan$ purity of EB (59.05%) and ${\beta}-glucan$ contents of EB (3.38 g/100 g) showed higher than those of others. Total sugar contents (0.61-1.17 mg/mL) showed that NEB and EB were higher than that of NEBE and EBE, EB had the highest total sugar content as 1.17 mg/mL, respectively. Protein contents (0.44-11.73 mg/mL) of NEBE and that of EBE were higher than that of NEB, that of EB. In FT-IR spectrum, the band at $890cm^{-1}$ of microcapsule was attributed to a ${\beta}-1,3-glucan$. The toxicities of ${\beta}-glucan$ from Phellinus baumii in both melanoma cell lines was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoli um bromide assay and ${\beta}-glucan$ from Phellinus baumii has no toxicity until $30{\mu}g/mL$. The effects of ${\beta}-glucan$ from Phellinus baumii on inhibition of cancer cell proliferation were detected by using a wound healing assay. The effect of NEB and EB were higher than NEBE and EBE, especially $30{\mu}g/mL$ of EB had the highest in both melanoma cell lines.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.26 no.2
• /
• pp.120-132
• /
• 1993

A continuous hollow fiber membrane reactor(CHFMR) was developed and optimized for the production of yellowfin sole(Limanda aspera) skin gelatin hydrolysates using trypsin. The results were summerized as follows: The $K_m$ value of the CHFMR was 2.4 times higher than that of the batch reactor, indicating reduced enzyme affinity for the substrate. The $K_2$ value of the CHFMR was 8.5 times lower than that of the batch process, showing a significant reduction in trypsin activity in the CHFMR. The optimum operating conditions for the CHFMR process were $55^{\circ}C$, pH 9.0, flux 7.79 ml/min, residence time 77min, and trypsin to substrate ratio, 0.01(w/w) After operating for 60min under the above conditions, $79\%$ of the total amount of initial gelatin was hydrolysed. Enzyme leakage was observed through the 10,000 MWCO membrane after the 20min of reactor operation, while none occurred after 5hr. Total enzyme leakage was about $12.95\%$ at $55^{\circ}C$ for 5hrs. However, there was no apparent correlation between enzyme leakage and substrate hydrolysis. The membrane has a significant effect on trypsin activity loss for 60min of the CHFMR operation. The CHFMR operating with the membrane lost $34\%$ of the initial activity versus a $23\%$ loss of activity after 3hr in the continuous reactor lacking the hollow fiber membrane. The measurement of fouling property showed that relative flux reduction was $91\%$ and flux recover rate was $92\%$ at $10\%$ substrate solution. The productivity(378.85mg product/mg enzyme) of the CHFMR was more than 4 times higher than that of the batch reactor at $55^{\circ}C$.

• Journal of the Korean Wood Science and Technology
• /
• v.38 no.4
• /
• pp.323-332
• /
• 2010

Petroleum-based adhesive resins have extensively been used for the production of wood panels. However, it is necessary to develop environmentally friendly adhesive resins due to the increase of manufacturing cost and the environmental issue, such as the emission of volatile organic compounds, of the pertroleum-based adhesive resins. This study was conducted to formulate environmentally friendly adhesive resins using by rapeseed flour (RSF), which is the by-product of bio-diesel produced from rapeseed, for replacing petroleum-based adhesives with them. To formulate RSF-based adhesive resins, RSF was hydrolyzed in de-ionized water, 1% and 3% sodium hydroxide solutions. As a crosslinking agent, PF prepolymers were prepared with 1.8, 2.1 and 2.4 mol formaldehyde and 1 mol phenol (1.8-, 2.1- and 2.4-PF), and then mixed with RSF hydrolyzates to complete the formulation of RSF-based adhesive resins. The RSF-based adhesive resins were applied to fabricate 3-ply plywood panels. The solid content of RSF-based adhesive resins were ranged from 26.08% to 36.12% depending on the hydrolysis condition of RSF and PF prepolymer type with a high viscosity. The tensile shear strength and wood failure of plywood fabricated with RSF-based adhesive resins exceeded a minimum requirement of KS standard for ordinary plywood regardless of the hydrolysis condition of RSF and PF prepolymer type. Formaldehyde emissions of the plywood panels fabricated with 1.8-PF and RSF hydrolyzates were lower than that of E0 specified in the KS standard. Based on the results, RSF might be used as a raw material of environmentally friendly adhesives for the production of plywood panels, but further researches - the increase of solid content of RSF-based adhesives for reducing press time and the microscopic observation of plywood specimen for identifying the relationship between tensile shear strength and the penetration of adhesives into wood structure - are required to commercialize the RSF-based adhesives.

• Applied Biological Chemistry
• /
• v.37 no.2
• /
• pp.130-141
• /
• 1994

A continuous two-stage membrane (1st-SCMR, MWCO 10,000; 2nd-SCMR, MWCO 5,000) reactor was developed and optimized for the production of fish skin gelatin hydrolysate with different molecular size distribution profiles using trypsin and pronase E. The optimum operating conditions in the 1st-step membrane reactor using trypsin were: temperature, $55^{\circ}C$ ; pH 9.0; enzyme concentration, 0.1 mg/ml; flux, 6.14 ml/min; reaction volume, 600 ml; and the ratio of substrate to trypsin, 100 (w/w). After operating for 1 hr under the above conditions, 79% of total amount of initial gelatin was hydrolysed. In the 2nd-step using pronase E under optimum operating conditions[temperature, $50^{\circ}C$ ; pH 8.0; enzyme concentration, 0.3 mg/ml; flux, 6.14 ml/min; reaction volume, 600 ml; and the ratio of substrate to pronase E, 33 (w/w)], the 1st-step hydrolysate was hydrolysed above 80%. Total enzyme leakages in the 1st-step and 2nd-step membrane reactors were about 11.5% at $55^{\circ}C$ for 5hrs and 9.0% at $50^{\circ}C$ for 4 hrs, respectively. However, there was no apparent correlation between enzyme leakage and substrate hydrolysis. The membrane has a significant effect on activity lose of trypsin and pronase E activity for 1 hr of the membrane reactors operation. The loss of initial activity of enzymes were 34% and 18% in the 1st-step and 2nd-step membrane reactor, whereas were 23% and 10% after operating time 3 hr in the 1st-step and 2nd-step membrane reactor lacking the membrane, respectively. The productivities of 1st-step and 2nd-step membrane reactor for 8 times of volume replacement were 334 mg and 250 mg per mg enzyme, respectively.

• The Korean Journal of Pharmacology
• /
• v.26 no.2
• /
• pp.219-226
• /
• 1990

Enalapril maleate tablets of two different producers were tested for bioequivalence. Enalapril is rapidly metabolized to an active metabolite, enalaprilat which inhibits angiotensin-converting enzyme (ACE). The pharmacokinetics of enalapril maleate and the time course of inhibition of plasma ACE activity after administration of the drugs were studied. Two single doses of 10mg each of enalapril maleate were administered orally to twelve male volunteers in a balanced, randomized, two-way crossover investigation. Plasma enalaprilat concentrations were determined over a 23-hour after the dose by enzyme inhibition assay and enalapril by the same method following in vitro hydrolysis. Urinary recoveries of enalapril and enalaprilat were determined for the calculation of renal clearance. Plasma ACE activity was determined by an enzyme assay. Peak plasma levels of enalapril were observed about 1 hour after the doses, and practically all enalapril had disappeared from plasma within 6 hour. Peak enalapril concentrations of both formulations were almost identical ($Vasotec^{\circledR}$, 61.38 ng/ml; $Beartec^{\circledR}$, 64.27 ng/ml). The values of the pharmacokinetic parameters of enalaprilat computed for $Vasotec^{\circledR}$ and $Beartec^{\circledR}$ tablets are presented in that order; area under the curve=330.63:320.96 $ng{\cdot}hr/ml$; peak concentration=38.63:39.43 ng/ml; time to peak=3.83:4.08 hour; elimination half-life=3.95:3.92 hours. No statistically significant difference was detected when area under the curve and all other parameters were compared. Using criteria of 95% confidence interval for the comparison of these parameters, only the upper limits of area under the curve and time to peak of enalapril were over 120%. All the parameters of enalaprilat were acceptable. Percent inhibition of plasma ACE to plasma enalaprilat concentration showed the sigmoid concentration-inhibition relationship. Time courses of plasma ACE inhibition after the administration of both formulations were quite similar. The formulations were found to be equivalent when compared on the premise that no significant difference was detected when pharmacokientic parameters and inhibition of ACE activity were compared, based on the confidence limits analysis.

• Food Science and Preservation
• /
• v.17 no.3
• /
• pp.311-319
• /
• 2010

Four saponins (1~4) were isolated from Akebia quinata pericarp through bioassay-guided fractionation. Pericarps of A. quinata were extracted with ethanol and sequentially fractionated with dichloromethane, ethyl acetate, butanol and water. Compounds 1~4 from the butanol fraction were identified as 3-O-${\alpha}$-L-arabinopyranosyl hederagenin (${\delta}$-hederin), 3-O-${\alpha}$-L-rhamnopyranosyl (1${\rightarrow}$2) ${\alpha}$-L-arabinopyranoly oleanolic acid (${\beta}$-hederin), 3-O-${\beta}$-D-xylopyranosyl (1${\rightarrow}$3) ${\alpha}$-L-arabinopyranosyl hederagenin (saponin C), and 3-O ${\alpha}$-L-rhamnopyranosyl (1${\rightarrow}$2) ${\alpha}$-L-arabinopyranosyl hederagenin (${\alpha}$-hederin) based on the spectroscopic evidences, respectively. Oleanolic acid and hederagenin were identified as the corresponding sapogenins by acid-hydrolysis. These compounds exhibited strong cytotoxic activity in MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxy-methoxyphenyl)-2-(4-sulfophenyl)-2H- tetrazolium, inner salt] assay on HepG2 cells. ${\beta}$-Hederin obviously attenuated the expression of bcl-2, an anti-apoptotic protein. All of the compounds also induced the activity of caspase-3, an apoptotic enzyme, while ${\alpha}$-hederin was the most potent activator of the enzyme. Our data demonstrate for the first time the apoptosis-inducing activity of A. quinata. These results suggest that A. quinata could be used as a potential source of natural cancer chemopreventive agents.