Jeongmi Lee

Multifunctional doxorubicin loaded superparamagnetic iron oxide nanoparticles for chemotherapy and magnetic resonance imaging in liver cancer

To develop a drug delivery system with enhanced efficacy and minimized adverse effects, we synthesized a novel polymeric nanoparticles, (YCC-DOX) composed of poly (ethylene oxide)-trimellitic anhydride chloride-folate (PEO-TMA-FA), doxorubicin (DOX) and superparamagnetic iron oxide (Fe(3)O(4)) and folate. The efficacy of the nanoparticles was evaluated in rats and rabbits with liver cancer, in comparison with free-DOX (FD) and a commercial liposome drug, DOXIL. YCC-DOX showed the anticancer efficacy and specifically targeted folate receptor (FR)-expressing tumors, thereby increasing the bioavailability and efficacy of DOX. The relative tumor volume of the YCC-DOX group was decreased two- and four-fold compared with the FD and DOXIL groups in the rat and rabbit models, respectively. Furthermore, YCC-DOX showed higher MRI sensitivity comparable to a conventional MRI contrast agent (Resovist), even in its lower iron content. In the immunohistochemical analysis, YCC-DOX group showed the lower expression of CD34 and Ki-67, markers of angiogenesis and cell proliferation, respectively, while apoptotic cells were significantly rich in the YCC-DOX group in terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. These results indicate that YCC-DOX is a promising candidate for treating liver cancer and monitoring the progress of the cancer using MRI.

Enhanced extraction of bioactive natural products using tailor-made deep eutectic solvents: application to flavonoid extraction from Flos sophorae

Green and efficient extraction of natural products from biomass is considered an important area of interest in the pharmaceutical and biochemical industries. Recently, deep eutectic solvents (DESs) have been gaining increasing interest as sustainable and safe solvents. In this study, we aimed to provide a practical example using a popular traditional Chinese medicine, Flos sophorae, showcasing the tuneability of DESs as designer solvents to selectively and efficiently extract bioactive compounds from biomass. As a result, a solvent called PG-1 that was tailor-made from a 2 : 5 mixture of L-proline and glycerol using a freeze-drying method was more effective than methanol for extraction of quercetin, kaempferol, and isorhamnetin glycosides from Flos sophorae. With PG-1-based ultrasound-assisted extraction (UAE), operational conditions including the DES content in the extractant, the extractant-to-sample solid ratio, and the ultrasound irradiation time for UAE were statistically optimized using a central composite design combined with a response surface methodology. The resulting extraction method in which 50 mg of sample powder was extracted by UAE for 45 min using 1.00 mL of an aqueous solution containing 90% w/w PG-1 was found to be a greener and more efficient process than common extraction methods such as methanol-based UAE and heat reflux extraction that are generally environmentally harmful. Based on the antioxidant activity measured by the DPPH assay, the tailor-made extractant exhibited an additive activity arising from its component, L-proline. Recovery of the extracted flavonoids from the DES, which was assessed using rutin, since it is the major flavonoid extracted, was 75% with the use of water as an anti-solvent, and could reach as high as 92% with the simple application of C18 solid phase extraction (SPE). In comparison, the recovery efficiency of the anti-solvent method was significantly reduced for the flavonoid glycosides from the real Flos sophorae extracts, while the efficiency of the SPE method was reasonably high (81–87%). The present study suggests that DESs are truly designer solvents that can be used as sustainable and safe extraction media for pharmaceutical and biochemical applications.

Simultaneous determination of 23 amino acids and 7 biogenic amines in fermented food samples by liquid chromatography/quadrupole time-of-flight mass spectrometry

A novel liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-Q-TOFMS) method was developed for the simultaneous determination of 23 amino acids and 7 biogenic amines in food samples. These analytes were pre-column derivatized with dansyl chloride and then separated in an Acquity column (1.7 μm; 2.1 mm × 100 mm). The separation of 31 compounds including an internal standard was achieved within 25 min at a flow rate of 0.2 mL/min. The method linearity for each amino acid and biogenic amine had a relatively wide range with r(2)>0.99. The intra- and inter-day precision, expressed as relative standard deviation (RSD), ranged from 1.1 to 4.6% and from 2.0 to 11.2%, respectively. The limit of detection was between 0.005 and 0.4 μg/mL. With a simple dilution, recoveries of around 80-120% were obtained for most of the compounds. No significant matrix effect was observed, and the developed method was successfully applied to the analysis of amino acids and biogenic amines in beer, cheese and sausage samples.

Comparison of ultraviolet detection, evaporative light scattering detection and charged aerosol detection methods for liquid-chromatographic determination of anti-diabetic drugs

Recently, charged aerosol detection (CAD), a new kind of universal detection method, has been widely employed in the HPLC system. In the present study, four kinds of anti-diabetic drug standards, glipizide, gliclazide, glibenclamide and glimepiride were determined by ultraviolet (UV) detection, evaporative light scattering detection (ELSD) and the aforementioned CAD. The results were compared with reference to linearity, accuracy, precision and limit of detection (LOD). All of the experiments were performed on a reverse phase column with water and acetonitrile as the mobile phase. Separations were achieved under the same chromatographic conditions for each detection method. As a result, CAD generated nearly uniform responses compared with UV detection and ELSD. It showed the best accuracy and LOD among 3 detectors and had similar precision with UV detection at higher concentrations while UV detection showed a better precision at lower concentrations than did CAD or ELSD. The LOD of CAD, in fact, can be up to two times higher than that of ELSD. The UV and ELSD linearity was satisfactory at R(2)>0.99, though in the case of CAD, a log-log transformation was needed. The proposed methods were also applied to the real anti-diabetic drugs and diabetes-related dietary supplements.

An in situ benzoylation-dispersive liquid-liquid microextraction method based on solidification of floating organic droplets for determination of biogenic amines by liquid chromatography-ultraviolet analysis

A novel analytical method consisting of in situ derivatization combined with liquid phase microextraction followed by liquid chromatography-ultraviolet detection (LC-UV) was developed to determine the biogenic amines (BAs) of alcoholic beverages. Nine BAs (putrescine, cadaverine, 1,3-diaminopropane, tryptamine, phenylethylamine, spermidine, spermine, histamine, and tyramine) were derivatized in situ with benzoyl chloride, extracted by dispersive liquid-liquid microextraction based on solidification of floating organic droplets (DLLME-SFO), and then chromatographed by LC-UV. Factors influencing the derivatization and extraction efficiency were optimized, including the reaction buffer pH and concentration, amount of derivatization reagent, reaction time, types and volumes of extraction and dispersive solvents, and extraction time. Under the optimized conditions, the method was linear over 0.05-8.0μgmL(-1) with an r(2)≥0.992 and exhibited intra- and inter-day precision less than 8.8% and 11.5%, respectively. The limit of detection ranged between 0.005 and 0.01μgmL(-1). The developed method using a basic LC-UV system is sensitive, rapid, convenient, green, and cost-effective. Moreover, it is versatile and practical for the analysis of BAs, as demonstrated by the successful application in four different types of popular alcoholic beverages (white wine, red wine, rice wine, and beer).

Comparison of primary and secondary metabolites for suitability to discriminate the origins of Schisandra chinensis by GC/MS and LC/MS.

Discrimination of the origins of plants as traditional medicinal herbs or functional foods is important to accurately comprehend their therapeutic effects or to appropriately utilize their qualities because different environmental backgrounds can induce diverse metabolic changes. In the present study, the origins of the herbal medicine Schisandra chinensis were differentiated using two instrumental approaches, GC/MS and LC/MS. The acquired data were processed using various programs to detect metabolites and statistically examined to measure the suitability of the methods. The R(2)X value of the PCA analysis was used to examine the identified metabolites as potential discriminative markers. The identification of markers by primary metabolites using GC/MS analysis was advantageous because of its reproducibility and the use of a constructed database. However, LC/MS analysis using secondary metabolites provided a greater number of distinguishable variables and higher qualitative R(2)X values for the markers, which suggested that determination of the origins of the plants was more favourable using secondary metabolites.

Metabolomic identification of biochemical changes induced by fluoxetine and imipramine in a chronic mild stress mouse model of depression

Metabolomics was applied to a C57BL/6N mouse model of chronic unpredictable mild stress (CMS). Such mice were treated with two antidepressants from different categories: fluoxetine and imipramine. Metabolic profiling of the hippocampus was performed using gas chromatography-mass spectrometry analysis on samples prepared under optimized conditions, followed by principal component analysis, partial least squares-discriminant analysis, and pair-wise orthogonal projections to latent structures discriminant analyses. Body weight measurement and behavior tests including an open field test and the forced swimming test were completed with the mice as a measure of the phenotypes of depression and antidepressive effects. As a result, 23 metabolites that had been differentially expressed among the control, CMS, and antidepressant-treated groups demonstrated that amino acid metabolism, energy metabolism, adenosine receptors, and neurotransmitters are commonly perturbed by drug treatment. Potential predictive markers for treatment effect were identified: myo-inositol for fluoxetine and lysine and oleic acid for imipramine. Collectively, the current study provides insights into the molecular mechanisms of the antidepressant effects of two widely used medications.

Effects of storage period and heat treatment on phenolic compound composition in dried Citrus peels (Chenpi) and discrimination of Chenpi with different storage periods through targeted metabolomic study using HPLC-DAD analysis

Dried Citrus peels, known as Chenpi in Chinese medicine, are a traditional medicine for the treatment of indigestion and inflammatory syndromes. In this study, we evaluated the effect of storage periods (1-year vs. 3-year) and heat treatment (90min vs. 3h at 120°C) on the total phenolic content (TPC) and bioactivity (anti-oxidant activity) of Chenpi. It was found that the long-term stored Chenpi had a higher TPC and superior 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity levels compared to the regular stored Chenpi, and that heat treatment increased both TPC and bioactivity. Subsequently, we developed and validated a high performance liquid chromatography with diode-array detection (HPLC-DAD) method to determine individual phenolic acids. Eleven phenolic compounds were determined in different Chenpi samples. Concentrations of total phenolic compounds were higher in long-term stored Chenpi and heat treatment raised the levels of those in regular stored Chenpi. In further study, a targeted metabolomic approach was applied to discriminate Chenpi with different storage periods. Two different phenolic acid fractions (free and ester) from the regular and long-term stored Chenpi were analyzed using the developed HPLC-DAD and the data were used in principal component analysis (PCA) on the HPLC-DAD peak areas of the 11 phenolic acids. Two principal components (PC1 and PC2) accounted for 87.1% of the variation between the regular and long-term stored Chenpi. In a two-dimensional plot of PC1 and PC2, the samples divided into four groups: two storage periods and two fractions.

A new analytical method to determine non-steroidal anti-inflammatory drugs in surface water using in situ derivatization combined with ultrasound-assisted emulsification microextraction followed by gas chromatography–mass spectrometry

Because of the high stability and potential toxic effects of non-steroidal anti-inflammatory drugs (NSAIDs), it is important to closely monitor their concentrations in the environment using a sensitive analytical method. In this study, a simple, rapid, efficient, and sensitive analytical method based on gas chromatography-mass spectrometry (GC-MS) was developed to determine the levels of seven common NSAIDs in various types of surface water. To simplify sample preparation, in situ derivatization using methyl chloroformate was combined with ultrasound-assisted emulsification microextraction. For selection and optimization of significant variables, experiments were statistically designed using Plackett-Burman design and central composite design. The resulting optimal conditions for derivatization and extraction were 100 μL of chloroform (extraction solvent), 10.0 mL of sample, and 240 μL of pyridine (catalyst as a base in derivatization). The optimized sample preparation coupled with optimized GC-MS analysis in selected ion monitoring mode provided good linearity from 0.010 to 5.0 ng mL(-1), and a limit of detection between 0.0050 and 0.010 ng mL(-1), good intra-day and inter-day precision (0.30-6.3% and 5.1-9.5%, respectively), and good accuracy (relative recovery; 91-117% at 0.20 ng mL(-1) and 77-105% at 2.5 ng mL(-1)). Compared with previously reported methods, the current method requires a small volume of sample and simple sample preparation steps for sensitive determination of NSAID levels using a conventional GC-MS system. The method was successfully applied to determine the levels of seven common NSAIDs in various types of surface water.

Determination of bioactive compounds in fermented soybean products using GC/MS and further investigation of correlation of their bioactivities

The active ingredients and bioactivities (anti-oxidant, anti-tyrosinase, anti-proliferative and estrogenic activities) of soybean and soybean products (Cheonggukjang, Meju, Makjang, Doenjang and soy sauce) produced by different fermentation processes were compared. There were high correlations between active ingredients and bioactivities. Free phenolic acids extracted from soybean products were identified and quantified by gas chromatography/mass spectrometry (GC/MS). Overall, the components and activities in fermented soybean products were different than those in soybeans. Total phenolic content (TPC), protein content (PC) and anti-oxidant activity increased as fermentation time increased. TPC and PC showed strong negative correlations with anti-oxidant activity. Doenjang and soy sauce, two long-term fermented products, showed lower total flavonoid content (TFC) and estrogenic activities than short-term fermented soybean products. This might be explained by the decomposition and hydrolysis of flavonoids due to the long fermentation time and high temperature. Strong anti-proliferative activity against cancer cell lines, which was highly correlated with TFC, was found in Meju and Cheonggukjang. Soybean and all fermented products except Meju exhibited effective tyrosinase inhibitory activities. Fermented products showed stronger estrogenic activity than soybeans, which was highly correlated with syringic acid.