Je Hyun Lee

A new triterpenoid from Alisma orientale and their antibacterial effect

A new triterpenoid, named alisol Q 23-acetate, as well as fourteen known terpenes, alisol B 23-acetate (2), alisol B (3), alismol (4), 10-O-methyl-alismoxide (5), alismoxide (6), 11-deoxyalisol C (7), 13β,17β-epoxyalisol B 23-acetate (8), 4β,12-dihydroxyguaian-6,10-diene (9), alisol C 23-acetate (10), alisolide (11), 16β-methoxyalisol B monoacetate (12), alisol A (13), 16β-hydroxyalisol B 23-acetate (14), alisol A 24-acetate (15) were isolated from the rhizomes of Alisma orientale. The structures of compounds (1–15) were identified based on 1D and 2D NMR, including 1H-1H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Among these isolates, antibacterial effect of compounds 2, 3, 10, and 15, major constituents of A. orientale was examined. The MIC values of compounds 2, 10, and 15 were 5–10 βg/mL against eight antibiotic resistant strains, which were lower than those from the positive controls (MICs of chloramphenicol and ampicillin were 5–80 μg/mL). Therefore, compounds 2, 10 and 15 exhibited the potent antibacterial activity.

A metabolomic approach to determine the geographical origins of Anemarrhena asphodeloides by using UPLC–QTOF MS

An ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF MS) method was developed for metabolite profiling of Anemarrhena asphodeloides Bunge from two different geographical origins. In this study, the metabolite profile data obtained using UPLC-QTOF MS was subjected to multivariate statistical analyses, such as the principal component analysis and the hierarchical clustering analysis, to compare metabolite patterns among A. asphodeloides samples. Furthermore, a metabolite selection method known as significance analysis of microarrays (SAM) was applied to further select metabolites and to identify key constituents to efficiently distinguish between geographical origins. The UPLC-QTOF MS analysis successfully classified 21 samples into two distinct groups according to their geographical origins. The validation method used to assess the analytical stability and accuracy of these data is also described. These results suggest that this proposed method is reliable, accurate, and effective for geographic classification of A. asphodeloides, thus guiding its proper use for therapeutic purposes.

Simultaneous determination of bioactive flavonoids in some selected Korean thistles by high-performance liquid chromatography.

In order to facilitate the quality control of some selected Korean thistles (Cirsii Herb), Cirsium japonicum var ussuriense, C. japonium var spinosissimum, C. setidens, C. pendulum, C. nipponicum, Carduus crispus, and Breea segetum, a simple, accurate and reliable high performance liguid chromatography method was developed for the simultaneous determination of the six flavonoids: luteolin 5-O-glucoside (1), luteolin 7-O-glucoside (2), hispidulin 7-O-neohesperidoside (3), luteolin (4), pectolinarin (5), and apigenin (6), which were selected as the chemical markers of the thistles. Separation was achieved on an Agilent Eclipse XDB-C18 column with a gradient solvent system of 0.1% trifluoroacetic acid aqueous-methanol at a flow-rate of 1.0 mL/min and detected at 254 nm. All six calibration curves showed good linearity (R2 > 0.991). The method was reproducible with intra- and inter-day variations of less than 6%. The recoveries were in the range of 90.01–100.05%. This analysis method was successfully utilized to quantify the six flavonoids in the 22 batches of the thistles. The results demonstrated that this method is simple, reliable and suitable for the quality control of this medicinal herb.

Metabolomics approach for the discrimination of raw and steamed Gastrodia elata using liquid chromatography quadrupole time-of-flight mass spectrometry

A liquid chromatography quadrupole time-of-flight mass spectrometry-based metabolomics approach was applied to metabolite profiling of Gastrodia elata in order to identify raw and steamed G. elata and explore potential biomarkers for each processing state. A statistical classification method, significant analysis of microarrays, was used to select influential metabolites from the different forms. Through metabolite selection, several potential biomarkers were determined and assigned by matching mass information with that of reference compounds or by comparing it with data in the literature. Furthermore, the developed method was cross-checked using two validation procedures. The first validation was performed simultaneously with the metabolite profiling of G. elata using all detected metabolites, and the second was performed after the metabolite profiling using representative standard compounds of G. elata. Overall, this study can be applied to quality assurance of G. elata.

Analysis of heterocyclic amines and β-carbolines by liquid chromatography–mass spectrometry in cooked meats commonly consumed in Korea

Heterocyclic amines (HAs), which form in meats during heating and cooking, are recognized as mutagenic and carcinogenic compounds. In this study, 13 HAs and 2 β-carbolines (BCs) were analyzed in cooked Korean meat products, including griddled bacon, griddled pork loin, boiled pork loin, boiled chicken meat, chicken meat stock, chicken breast for salad and chicken patty. The samples were either cooked in the laboratory or purchased from local fast-food restaurants. The HAs and BCs in the samples were separated using solid-phase extraction and were analyzed by high performance liquid chromatography–mass spectrometry (HPLC–MS). The most frequently detected HAs and BCs in the cooked meats were harman (1-methyl-9H pyrido[4,3-b]indole; 990.9 ng g−1), norharman (9H-pyrido[4,3-b]indole; 412.7 ng g−1) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine; 258.2 ng g−1). The griddled pork loin and bacon contained higher levels of norharman, harman and PhIP than the other cooked meats. PhIP, which is classified as a Group 2B carcinogen by the International Agency for Research on Cancer, had levels of 258.2 and 168.2 ng g−1 in the griddled pork loin and griddled bacon, respectively. The griddled bacon was the only sample containing TriMeIQx (2-amino-3,4,7,8-tetramethylimidazo[4,5-f]quinoxaline; 79.9 ng g−1). IQ (2-amino-3-methyl imidazo[4,5-f]quinoline), 7,8-DiMeIQx (2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline), 4,8-DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline) and AαC (2-amino-9H-pyrido[2,3-b]indole) were detected at trace levels in all samples.