• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.61-65
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• 2018

In this study, the conversion of glucosamine, which is a major monomer in chitin/chitosan of crustacean shell, using solid acid catalyst was performed to obtain chemical intermediates such as levulinic acid and 5-hydroxymethyl furfural (5-HMF). The conversion reaction was optimized with four reaction factors of selection of ionic resin catalyst, reaction temperature, catalyst amount, and reaction time. As an optimized result, the highest levulinic acid yield was achieved approximately 36.86% under the determined conditions (Amberlyst 15 as a solid-acid catalyst, $180^{\circ}C$, 5% catalyst amount and 60 min). On the other hand, 5-HMF yield was found to be 0.91% at the condition.

• YAKHAK HOEJI
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• v.29 no.1
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• pp.32-38
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• 1985

The anthelmintic substance of the roasted fruits of Prunas mume against Clonorchis sinensis was isolated and its structure was identified by chemical and physical methods. The results obtained from the experiments are as follows: 1) The methanol extract of the roasted fruits of P. mume was fractionated into four parts: petroleum ether, ethyl ether, ethyl acetate and water soluble part. Among these, etherial fraction was found to have strong wormicidal effect on liberated metacercaria of Clonorchis sinensis. 2) From the etherial fraction, the wormicidal substance was isolated by silica gel, polyamide and sephadex column chromatography and identified to be 5-hydroxymethylfurfural (5-HMF) by chemical and spectral data. 3) 5-HMF was synthesized and administered to the rabbits infected with C. sinensis. On the 2nd day after administration, the EPG (eggs per gram in feces) reached to the maximal value. Among the adult worms isolated from the bile duct of the treated animal, 84% of worms were damaged morphologically. 4) The content of 5-HMF in the fruits of P. mume which were roasted in an oven at $90-110^{\circ}C$ for 52 hours and that in the fresh fruits was evaluated by HPLC. The content of 5-HMF was 0.8% in the roasted fruits and 0.02% in the fresh ones.

• Journal of the Korean Wood Science and Technology
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• v.37 no.6
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• pp.578-584
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• 2009

We investigated acid hydrolysis characteristics of yellow poplar woodmeal with concentrated sulfuric acid for high concentration of monosaccharides production. Woodmeal to 72% sulfuric acid ratio (w/w), $2^{nd}$ hydrolysis temperature and time were main variables for finding optimum reaction condition. Optimum woodmeal to 72% sulfuric acid ratio was 1 : 2.61 (w/w) and $2^{nd}$ hydrolysis temperature and time was $105^{\circ}C$ and 40 min as 44.8 g/L of glucose and 25.2 g/L of xylose in hydrolysis solution. In this acid hydrolysis solution, furfural, 5-HMF, low molecular weight phenolic compounds were identified. Furfural and 5-HMF concentration were increased as increasing $2^{nd}$ hydrolysis time. More than 40 min of $2^{nd}$ hydrolysis at $110^{\circ}C$, xylose concentration was decreased but glucose concentration was leveled out because xylose to furfural reaction was faster than xylan to xylose, but cellulose to glucose reaction was similar rate with glucose to 5-HMF at that $2^{nd}$ hydrolysis reaction condition.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.5
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• pp.823-829
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• 2011

This study was performed to obtain the good processing in the Rehmanniae Radix Preparata. In this study, we investigated the comparative analysis for steamed and hot-air dried Rehmanniae Radix Preparata. The results were obtained as follows : Through loss on drying analysis with each additional processing of Rehmanniae Radix preparata, there was gradual increase. Through ash analysis with each additional processing of Rehmanniae Radix preparata, there was slight increase. Rehmanniae Radix preparata had several inorganic components such as K, P, Mg, Ca, Cl, Al. P and Mg were increased gradually with each additional processing of Rehmanniae Radix Preparata. But Ca was decreased with each additional processing. We identitied 24 kinds of volatile components from extracts of various processed Rehmanniae Radix Preparata through componential analysis using GC/MS. From GC/MS analysis, we found out the content of 5-HMF Rehmanniae Radix Preparata steamed over 7 times was suitable. 5-HMF's content of 9 times steamed Rehmanniae Radix Preparata gained from GC/MS analysis is 70-fold higher than gained from HPLC. The more it is repeating steamed and hot-air dried, the more toxic volatile compound of Rehmanniae Radix Preparata is removed. Taken together, these results suggested that Rehmanniae Radix Preparata had component (especially 5-HMF) changes according to different processed steaming and hot-air drying.

• Journal of Pharmacopuncture
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• v.21 no.2
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• pp.112-119
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• 2018

Contents of compounds in Rehmanniae Radix change depending on the number of steaming and drying and the drying method. In this study, as an impregnation method for dried Rehmanniae Radix, takju impregnation and cheongju impregnation were carried out and steaming and drying were repeated for 9 times. The changes of 5-HMF and catalpol contents were analyzed according to the number of repetition times to investigate which stage of steaming and drying is preferable. Also, total nitrogen, crude fat, ash, and crude fiber were measured to analyze changes in general components. 5-HMF was not detected in dried Rehmanniae Radix. As a result of repetitive steaming and drying, the content of 5-HMF increased only slightly from 1 to 4-times steaming and drying but increased significantly from 5-times. The catalpol in dried Rehmanniae Radix was not detected after 5 times of steaming and drying. Sucrose, maltose, and glucose were included in dried Rehmanniae Radix before steaming and drying. However, after the process in both Takju impregnation and Cheongju impregnation, galactose and fructose tended to decrease after production and sucrose and glucose tended to decrease after the increase. In this study condition, 6-times and more steaming and drying were appropriate process which met the content criteria (not less than 0.1%) of the Korean Pharmacopoeia (8th edition) for 5-HMF, an index component for quality control of Rehmanniae Radix Preparata.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.204.1-204.1
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• 2003

Rehmanniae Radix Preparata attributes good blood circulation and it has been used for the treatment of dizziness, men's sterility, excessive loss of blood and weakness. On the quality control of the commercial Rehmanniae Radix Preparata, quantitative determination of 5-hydroxymethyl-2-furaldehyde (5-HMF) using HPLC method has been conducted. Quantitative analysis of 5-HMF in Rehmanniae Radix Preparata showered average 0.121${\pm}$0.063% in 14 samples collected throughout the regions of Korea. Contents of loss on drying, residue on ignition and residue on acid insoluble ignition showered average 14.084${\pm}$2.804%, 3.415${\pm}$0.790% and 0.807${\pm}$0.474% respectively.

• Korean Journal of Pharmacognosy
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• v.36 no.3 s.142
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• pp.235-239
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• 2005

Changes in chemical composition of the ethanolic extract of roasted Asparagi Tuber were investigated by HPLC. One dramatically increased peak $(t_R\;14.85 min)$ was isolated by silica gel column chromatograph and identified as 5-hydroxymethyl furfural (HMF) by comparing its $1^H-NMR$ data with that of a commercial standard. HMF content reached its maximum level at $190^{\circ}C$ for 60 minutes. Under these conditions, HMF contents in the roasted Asparagi Tuber was increased about thirteen times (9.26mg/g) over the not-roasted control (0.71 mg/g). No significant differences were found in macrophage-activating, prolyl endopeptidase-inhibiting, antioxidative (DPPH), anti-coagulating (activated partial thromboplastin times), and ACE-inhibiting activities between roasted and not-roasted Asparagi Tuber.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.20 no.1
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• pp.1-13
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• 1994

An antioxidative compound was isolated from pine needles. This compound was identified as 4-hydroxy-5-methyl-3[2H]-furanone on the basis of spectroscopic evidences. It scavenged 1,1-diphenyl-2-picrylhydrazyl free radicals more efficiently than maltol and tocopherol did. It exhibited an inhibitory effect on the lipid peroxidation of rat liver microsome induced by Fe(ll)/ascorbate, and the protective effect against UV cytotoxicity in cultured human fibroblasts. In addition, HMF appeared to prevent the cellular melanogenesis in the cultured murine melanoma cells, more effectively than kojic acid, a well known inhibitor of melanogenesis, while the former was not so effective as the latter for the inhibilion of the tyrosinase. Considering that cellular melanogenesis is a metabolic process triggered by oxidative stress, it was tentatively deduced that the antioxidative property of HMF may afford the effect against cellular pigmentation by alleviating the causative stress. This study provided a novel inhibitor of melanogenesis, that might be useful for the cosmetic applications.

• KSBB Journal
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• v.24 no.3
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• pp.267-272
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• 2009

During a dilute acid hydrolysis, degradation products are formed or liberated by pre-treatment of lignocelluloses depend on both the biomass and the pretreatment conditions such as temperature, time, pressure, pH, redox conditions, and addition of catalysts. In lignocellulosic biomass, sugars can be degraded to furfural which is formed from pentoses and 5-hydroxymethulfurfural (HMF) from hexoses. 5-HMF can be further degraded, forming levulinic acid and formic acid. Acetate is liberated from hemicellulose during hydrolysis. Some decomposed compounds hinder the subsequent bioconversion of the solubilized sugars into desired products, reducing conversion yields and rates during fermentation. In the present work, samples of rapeseed strawwere hydrolyzed to study the optimal pretreatment condition by assessing yields of sugars and decomposed products obtained under different reaction conditions ($H_2SO_4$ 0.5-1.25% (w/w), reaction time 0-20 min and temperature range 150-220 C). A careful analytical investigation of acid hydrolyzate of rapeseed straw has not yet been undertaken, and a well-closed mass balance for the hydrolyzate in general is necessary to verify the productivity and economic predictions for this process.

• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.289-294
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• 2007

This study was performed to investigate the effects of pre-soaking methods on the preparation of Rehmannia radix Preparata (R.P). The R. radix L (R.L) was soaked in distilled water and traditional Korean wine for 24 hr, then the soaked R.L was treated with a traditional nine-time steaming process. Next, catalpol, 5-hydroxymethyl-2-furaldehyde (5-HMF), polyphenols, flavonoids, antioxidant activities, and ACE inhibition activity were analyzed for the R.P produced by the different methods. The catalpol content of the R.L was 631.4 ppm, but the content decreased as steaming increased to 8-9 times. The 5-HMF, polyphenol, and flavonoid contents of the R.L were 0.12 mg/g, 5.09 mg/g, and 0.83 mg/g, respectively, and these increased gradually with increasing steaming times. As the steaming times of the distilled soaking water increased, the antioxidant activities of 1 mg/mL increased from 19.44% to 75.60% at 14 times of steaming. The ACE inhibition activities of 1 mg/mL of the distilled soaking water increased from 28.70% to 94.78% at 10 times of steaming, but decreased afterward.