• Journal of Veterinary Science
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• v.21 no.2
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• pp.32.1-32.13
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• 2020

Levofloxacin pharmacokinetic profiles were evaluated in 6 healthy female rabbits after intravenous (I/V), intramuscular (I/M), or subcutaneous (S/C) administration routes at a single dose of 5 mg/kg in a 3 × 3 cross-over study. Plasma levofloxacin concentrations were detected using a validated Ultra Performance Liquid Chromatography method with a fluorescence detector. Levofloxacin was quantifiable up to 10 h post-drug administration. Mean AUC_0-last values of 9.03 ± 2.66, 9.07 ± 1.80, and 9.28 ± 1.56 mg/h^*L were obtained via I/V, I/M, and S/C, respectively. Plasma clearance was 0.6 mL/g*h after I/V administration. Peak plasma concentrations using the I/M and S/C routes were 3.33 ± 0.39 and 2.91 ± 0.56 ㎍/mL. Bioavailability values, after extravascular administration were complete, - 105% ± 27% (I/M) and 118% ± 40% (S/C). Average extraction ratio of levofloxacin after I/V administration was 7%. Additionally, levofloxacin administration effects on tear production and osmolarity were evaluated. Tear osmolarity decreased within 48 h post-drug administration. All 3 levofloxacin administration routes produced similar pharmacokinetic profiles. The studied dose is unlikely to be effective in rabbits; however, it was calculated that a daily dose of 29 mg/kg appears effective for I/V administration for pathogens with MIC < 0.5 ㎍/mL.

• Journal of Animal Science and Technology
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• v.64 no.6
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• pp.1245-1258
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• 2022

This study was conducted to determine the effect of natural ingredient seasoning on the reduction of heterocyclic amine (HCA) production that may occur when pork belly is cooked at a very high temperature for a long time. Pork belly seasoned with natural ingredients, such as natural spices, blackcurrant, and gochujang, was cooked using the most common cooking methods, such as boiling, pan fry, and barbecue. HCAs in pork belly were extracted through solid-phase extraction and analyzed via high-performance liquid chromatography. For short-term toxicity, a mouse model was used to analyze weight, feed intake, organ weight, and length; hematology and serology analysis were also performed. Results revealed that HCAs formed only when heating was performed at a very high temperature for a long time, not under general cooking conditions. Although the toxicity levels were not dangerous, the method showing the relatively highest toxicity among various cooking methods was barbecue, and the natural material with the highest toxicity reduction effect was blackcurrant. Furthermore, seasoning pork belly with natural materials containing a large amount of antioxidants, such as vitamin C, can reduce the production of toxic substances, such as HCAs, even if pork belly is heated to high temperatures.

• Korean Journal of Pharmacognosy
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• v.53 no.2
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• pp.111-118
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• 2022

Chestnut honey is a sweet dark-colored honey with a distinct bitter aftertaste. It contains numerous phenolic compounds and alkaloids and is noted for its antioxidant and anti-inflammatory activities. However, it has been established that there are differences in the composition and activity of chestnut honey constituents depending on the region of origin, the sources of which warrant further research. In this study, we analyzed the kynurenic acid (KA) contents in chestnut honey produced in nine different regions in Korea, using high-performance liquid chromatography in conjunction with ultraviolet detection, and validated the analytical method developed. Use of a reverse-phase column and detection at a wavelength of 240 nm were found to be optimal for the detection of KA. Similar evaluation of an optimal method for extracting KA from chestnut honey revealed that extraction using 10% EtOH at 20 times the sample volume over a 6 h period was the most suitable for obtaining a high content of KA. Among the nine regional chestnut honeys assessed, KA content was found to be highest in the "Gongju" sample (1.14 mg/g), followed by that in the "Cheongdo" and "Damyang" samples. Validation of the KA analytical method revealed a good analyte linearity, with a correlation coefficient (r²) of 0.9995, an accuracy of between 92.37% and 107.35%, and good precision (RSD ≤ 1.05%). Our findings in this study, based on a validated quantitative analytical method for KA, could make an important contribution to establishing a data profiling procedure for characterizing chestnut honeys produced in different regions, and may also provide basic data for the identification of functional honey.

• Natural Product Sciences
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• v.28 no.4
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• pp.168-180
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• 2022

Ephedra is a genus of the Ephedraceae family and is found in temperate regions, such as Central Asia and Europe. Among the various ephedra species, Ma Huang (Ephedra herb) is derived from the aerial parts of Ephedra sinica S tapf, Ephedra equisetina Bunge, and Ephedra intermedia Schrenk & C.A. Mey. Ma Huang contains various ephedra alkaloids, including (-)-ephedrine, (+)-pseudoephedrine, (-)-norephedrine, (+)-norpseudoephedrine, (-)-methylephedrine, and (+)-methylpseudoephedrine, which are found naturally as single enantiomers, although they can be prepared as racemates. Although the use of Ma Huang in foods is prohibited in Korea, products containing Ma Huang can be imported, and so it is necessary to develop a suitable analytical technique for the detection of Ma Huang in foods. Herein, we report the development of analytical methods for the detection of ephedra alkaloids in products containing Ma Huang. Following sample purification by solid phase extraction, quantitative analysis was performed using ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS). Additionally, the enantiomers were successfully separated using HPLC-DAD. We successfully analyzed various food samples, where the ephedra alkaloids were qualitatively and quantitatively determined, and the enantiomers were separated. It is expected that these methods may contribute toward preventing the distribution of illegal products containing Ma Huang.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.428-437
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• 2023

A simultaneous analytical method was developed and validated for the analysis of prohibited fluoroquinolone (FQ) antibiotics including norfloxacin, ofloxacin, and pefloxacin, released by aquaculture in seawater and effluents. The samples were filtered, and extracts were obtained using a solid phase extraction cartridge with methanol (MeOH). The extracts were concentrated, and analyzed using ultra-performance liquid chromatography-tandem mass spectrometry. Two different columns and four different mobile phases were compared to achieve optimal separation and sensitivity for target compounds. Typical validation parameters including linearity, recovery of surrogate standard, instrument detection limit (IDL), limit of quantification (LOQ), and method detection limit (MDL) were evaluated. The linearity of calibration curves was over 0.999. Recoveries of surrogate ranged from 87.6% to 113%. The LOQ of target compounds was approximately 3-8 times lower than those reported in previous studies. The IDL and MDL were 0.06-0.57 and 0.06-0.37 ng/L, respectively. Seven effluent samples collected from an aquaculture located in Jeju were analyzed; however, not all target compounds were detected in the samples, suggesting that the banned antibiotics were not used. Overall, this established method was able to simultaneously analyze the three FQ antibiotics, and may be useful for monitoring prohibited antibiotics in the fishery industry.

• Journal of Korean Medicine for Obesity Research
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• v.23 no.1
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• pp.10-17
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• 2023

Objectives: The aim of this study was to compare the total phenolic content of Korean Acanthopanax senticosus stems harvested in different seasons and provide basic data for developing functional reinforcement products based on the optimal harvesting time. Methods: Each sample harvested in different seasons was extracted and concentrated twice for 2 hours using 70% ethyl alcohol. Phenolic compounds were analyzed using high-performance liquid chromatography for simultaneous multi-component analysis of 14 compounds, including syringaresinol and so on. Results: The results showed that the stem of Korean Acanthopanax senticosus harvested in winter (November 29th) (EAS-5) had the highest phenolic content of 1.038%. The stem of Korean Acanthopanax senticosus harvested in autumn (October 1st) (EAS-4) showed the second-highest phenolic content of 0.764%, followed by the stem of Korean Acanthopanax senticosus harvested in spring (February 2nd) (EAS-1) with a content of 0.390%. On the other hand, the stem of Korean Acanthopanax senticosus harvested in the summer (June 2nd) (EAS-3) showed the lowest content at 0.342%. In conclusion, the stem of Korean Acanthopanax senticosus harvested in winter (EAS-5) showed the highest phenolic compound content. Conclusions: Considering the extraction yield and the total phenolic content, as well as the concentrations of key functional components such as eleutheroside B, chlorogenic acid, and syringaresinol in the 70% ethyl alcohol extract of Korean Acanthopanax senticosus, it is suggested that the stems of Korean Acanthopanax senticosus harvested during the winter season are suitable for the development of novel materials with enhanced anti-obesity functionality.

• Restorative Dentistry and Endodontics
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• v.46 no.2
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• pp.26.1-26.15
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• 2021

Objectives: The aim of the present systematic review was to investigate the cryopreservation process of dental pulp mesenchymal stromal cells and whether cryopreservation is effective in promoting cell viability and recovery. Materials and Methods: This systematic review was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and the research question was determined using the population, exposure, comparison, and outcomes strategy. Electronic searches were conducted in the PubMed, Cochrane Library, Science Direct, LILACS, and SciELO databases and in the gray literature (dissertations and thesis databases and Google Scholar) for relevant articles published up to March 2019. Clinical trial studies performed with dental pulp of human permanent or primary teeth, containing concrete information regarding the cryopreservation stages, and with cryopreservation performed for a period of at least 1 week were included in this study. Results: The search strategy resulted in the retrieval of 185 publications. After the application of the eligibility criteria, 21 articles were selected for a qualitative analysis. Conclusions: The cryopreservation process must be carried out in 6 stages: tooth disinfection, pulp extraction, cell isolation, cell proliferation, cryopreservation, and thawing. In addition, it can be inferred that the use of dimethyl sulfoxide, programmable freezing, and storage in liquid nitrogen are associated with a high rate of cell viability after thawing and a high rate of cell proliferation in both primary and permanent teeth.

• Analytical Science and Technology
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• v.21 no.5
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• pp.424-431
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• 2008

Streptomycin, which is one of aminoglycoside antibiotics, has been widely used in the rearing of food-producing animals to prevent and treat diseases in cattle, pigs and poultry. Although not licensed in South Korea, streptomycin has also been used for the treatment of bacterial honeybee disease, such as European foulbrood in Third World countries. A reliable and effective method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of streptomycin in honey. A established method was optimized the clean-up and extraction procedure for the trace determination, good precision and accuracy. And the chromatographic and tandem mass spectrometric parameters were also optimized. The precision (RSD) and accuracy (bias) in the concentration range of 5.0~50.0 ug/kg were 5.5~14% and -10.0~8.0%, respectively. Limit of detection was 0.75 ug/kg and recovery of streptomycin spiked at level of 10 ug/kg in honey was 74%. The established and validated method was applied to determine streptomycin in honey which was on the market.

• Analytical Science and Technology
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• v.20 no.2
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• pp.164-169
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• 2007

A selective analytical method of LC/MS/MS has been applied to determine the levels of acrylamide in food products. Food samples were 17 including 6 potato chips, and 11 french fries. The analysis of food samples includes extraction with DDDW, clean-up using C18 and mixed ion exchange SPE cartridges and detection by liquid chromatography tandem mass spectrometry. The mobile phase was a mixture of 0.1 % acetic acid and 0.5 % methanol in water. The target ions were identified and determined by ESI mass spectrometer. The overall recoveries were ranged from 91 % to 101 % and the limit of quantitation was $10{\mu}g/kg$. Depending on food kinds, the levels of acrylamide were variable and the average was 0.71 mg/kg for potato chips, and 0.34 mg/kg for french fries.

• Analytical Science and Technology
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• v.21 no.5
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• pp.403-411
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• 2008

Dimethyldibutyltetradecylmalonamide (DMDBTDMA) extractant was used in a solvent extraction process for a radioactive liquid waste treatment. For the study of radiolysis phenomena, DMDBTDMA was synthesized and the degradation compounds (n-methylbutylamine, tetradecane, 1-tetradecanol) in the DMDBTDMA extractant, irradiated with $^{60}Co$ gamma ray, were identified and determined as radiolysis products by a Fourier transform infrared (FT-IR), gas chromatograph/mass spectrometer (GC/MS) analysis and GC/MS with selected ion monitoring (SIM) mode. Retention behavior of n-methylbutylamine, n-dodecane, tetradecane and 1-tetradecanol in the total ion chromatogram with the standard materials and n-dodecane as the internal standard (ISTD) were 2.35 min., 8.83 min., 10.68 min. and 12.75 min., respectively. In the case of tetradecane, there was a linear relationship between the concentration of the tetradecane and the absorbed dose of the ${\gamma}$-ray irradiated DMDBTDMA.