• Bulletin of the Korean Chemical Society
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• v.24 no.12
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• pp.1757-1762
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• 2003

The interrelation between retention factors of several L-amino acids and their physico-chemical and structural properties can be determined in chromatographic research. In this paper we describe a predictor for retention factors with various properties of the L-amino acids. Eighteen L-amino acids are included in this study, and retention factors are measured experimentally by RP-HPLC. Binding energy ($E_b$), hydrophobicity (log P), molecular refractivity (MR), polarizability (${\alpha}$), total energy ($E_t$), water solubility (log S), connectivity index (${\chi}$) of different orders and Wiener index (w) are theoretically calculated. Relationships between these properties and retention factors are established, and their predictive and interpretive ability are evaluated. The equation of the relationship between retention factors and various descriptors of L-amino acids is suggested as linear and multiple linear form, and the correlation coefficients estimated are relatively higher than 0.90.

• Bulletin of the Korean Chemical Society
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• v.24 no.9
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• pp.1265-1268
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• 2003

The estimation of retention factors by correlation equations with physico-chmical properties maybe helpful in chromatographic work. The physico-chemical properties were water solubility (S), hydrophobicity (P), total energy ($E_t$), connectivity index 1 ($^1{\chi}$), hydrophilic-lipophlic balance (x) and hydrophilic surface area (h) of isoflavones. The retention factors were experimentally measured by RP-HPLC. Especially, the empirical regulations of water solubility and hydrophobicity were expressed in a linear form. The equation between retention factors and various physico-chemical properties of isoflavones was suggested as $k = a_0 + a_1\;log S + a_2log\;P^Q + a_3(E_t) + a_4(^1{\chi}) + a_5(x) + a_6(h)$, and the correlation coefficients estimated were relatively higher than 0.95. The empirical equations might be successfully used for a prediction of the various chromatographic characteristics of substances, with a similar chemical structure.

• Journal of Pharmaceutical Investigation
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• v.16 no.3
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• pp.106-109
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• 1986

The elution of di(2-ethylhexyl) phthalate (DEHP) from flexible bags into human blood or transfusion was studied. The conditions of determination of DEHP using high performance liquid chromatography (HPLC) was established as follows: Condition I-column, ${\mu}-Bondapak^{TM}\;C_{18}$; mobile phase, methanol: water=91 : 9 ; flow rate, 1.2ml/min; wavelength, 254nm; injection volume, $10{\mu}l$. Condition II-column, Lichorsorb RP-18$(10{\mu}m)$; mobile phase, methanol: water=94 : 6 ; flow rate, 1.1ml/min; wavelength, 254nm; injection volume, $10{\mu}l$. DEHP was found to be migrating from PVC blood and total parentral nutrient bags into methanol, but not into anti, coagulant drug solution.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.202.1-202.1
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• 2003

Six compounds were isolated from the 90% MeOH fraction of the vine stem of Spatholobus suberectus Dunn (Leguminosae) using silica gel, reverse phase column chromatography and RP-HPLC. Structures of compounds 1-6 were elucidated by spectroscopic parameters of IR, E1 MS, FAB MS, lD-NMR and 2D-NMR spectrum and identified as pseudobaptigenin (1), genistein (2), (2R)-7-hydroxy-6-methoxyflavanone (3), (3R,4R)-2",4"-dihydroxy-6,7-methylenedioxy-isoflavan-4-ol (4), (3R,4R)-7,2" -dihydroxy- 4"-methoxyisoflavan-4-ol (5), sativan (6), respectively. Compounds 3, 4 and 5 have been newly reported in nature.

• Natural Product Sciences
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• v.29 no.1
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• pp.17-23
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• 2023

A phytochemical investigation of the fruits extract of Melia toosendan afforded the isolation of two new nor-neolignans, meliasendanins E (1) and F (2), as well as twelve known compounds (3 - 14) using various separation technique such as Diaion HP20, silica, RP-18 gel column chromatography and semi-preparative HPLC. Their chemical structures were elucidated by extensive NMR spectroscopic data including 2D-NMR, and HR-ESI-MS as well as ECD data. Among the twelve known compounds, the absolute structures of 3 - 6 were determined first, and given the trivial names as meliasendanins G-J (3 - 6). Based on the evaluation of anti-inflammatory activity, compounds 7 - 8 exhibited inhibitory effects on LPS-induced nitric oxide production in RAW 264.7 macrophages with IC₅₀ values of 34.6 and 39.5 µM, respectively.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.199-202
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• 2008

A high performance liquid chromatographic (HPLC) method for the simultaneous determination of hesperidin and glycyrrhizin was established for the quality control of traditional herbal medicinal preparation, Pyungwi-san (PWS). Separation and quantification were successfully achieved with a Waters XTerra RP18 column ($5{\mu}m$, 4.6 mm I.D. ${\times}$ 150 mm) by gradient elution of a mixture of acetonitrile and water containing 0.03% phosphoric acid (pH 2.03) at a flow rate of 1.0 ml/min. The diode-array UV/vis detector (DAD) was used for the detection and the wavelength for quantification was set at 230 nm. The presence of hesperidin and glycyrrhizin in this extract was ascertained by retention time, spiking with each authentic standard and UV spectrum. All four compounds showed good linearity $(r^2>0.995)$ in a relatively wide concentration ranges. The R.S.D. for intra-day and inter-day precision was less than 7.0% and the limits of detection (LOD) were less than 60 ng. The mean recovery of each compound was 99.0-105.6% with R.S.D. values less than 4.0%. This method was successfully applied to the determination of contents of hesperidin and glycyrrhizin in three commercial products of PWS. These results suggest that the developed HPLC method is simple, effective and could be readily utilized as a quality control method for commercial PWS products.

• Journal of Life Science
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• v.23 no.8
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• pp.1025-1031
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• 2013

From a 95% ethanolic extract of H. diffusa, four marker compounds (HD1~HD4) were isolated, which were relatively unique and exist in comparably high contents. The structures of marker compounds were identified as digitolutein (1), 2-hydroxy-3-methylanthraquinone (2), (E/Z)-6-O-p-coumaroyl scandoside methyl ester (4:1 mixture) (3), and (E/Z)-6-O-p-methoxycinnamoyl scandoside methyl ester (4:1 mixture) (4), respectively, on the basis of $^{13}C$ and $^1H$-NMR analyses. The calibration curves of marker compounds showed high linearity, as their correlation coefficient ($R^2$) were in the range of 0.9991~0.9999. In addition, the limit of detection (LOD) and the limit of quantification (LOQ) were $0.03{\sim}0.07{\mu}g/ml$ and $0.099{\sim}0.231{\mu}g/ml$, respectively. The intra-day/inter-day precision and accuracy were 0.23~2.00%/0.25~1.16% and 94.60~108.44%/94.73-110.23%, respectively. The optimal HPLC conditions for the simultaneous quantification of HD1~HD4 were as follows: stationary phase; Merck Chromolith RP-18e ($100{\times}4.6mm$, $5{\mu}m$), column temp.; room temperature, UV detection at 280 nm, flow rate; 2.0 ml/min, injection volume; $10{\mu}l$, mobile phase; start with the mixture of 80% solvent A ($H_2O$ containing 0.5% acetic acid) and 20% solvent B (methanol containing 0.5% acetic acid) and gradually decrease solvent A to 40% in 9 min., then retain this condition to 18 min. Under the HPLC condition, the four marker compounds 1~4 were successfully separated without any interference of other constituents. The results obtained in this study are expected to be helpful for the development of nutraceutics and natural medicines and for the quality control of this plant.

• KSBB Journal
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• v.16 no.1
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• pp.71-75
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• 2001

Acanthoside-D, contained in Acanthopanax chilsanensis is known as a ginseng-like substance. This work was focused to set up analytical and preparative conditions for Acanthoside-D purification. The ethanol extract from the powder of the trunk of Acanthopanax chilsanensis was partitioned with hexane. A $\mu$-Bondapak $C_{18}$ (3.9$\times$300 mm, $10\mu\textrm{m}$) column was used to separate Acanthoside-D from the trunk of Acanthopanax chilsanensis. From the experimental results, the mobile phase used for isolating Acanthoside-D from the extract was water/acetonitrile/methanol=80/14/6 %(v/v). The flow rate of mobile phase was 1.0 mL/min, and UV wavelength was fixed at 210 nm. Finally on a semi-preparative column (3.9$\times$ 300 mm, $15\mu\textrm{m}$, Lichrospher 100RP-18) with the same mobile phase composition, the allowable maximum injection volume increased to 250 $\mu\ell$

• KSBB Journal
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• v.14 no.5
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• pp.517-522
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• 1999

A green tea used in this experiment was cultivated at Bosung (Chonnam) and purchased from a domestic market. The extract at 5$0^{\circ}C$ water from the powder of green tea partitioned with chloroform and ethyl acetate. The resulting solution was further purified with a chromatographic column (4.6$\times$250 mm, 15${\mu}{\textrm}{m}$, Lichrospher 100RP-18). Finally separation was achieved on a $\mu$-Bondapak $C_18$(3.9$\times$300mm, 10${\mu}{\textrm}{m}$) column. The elution order of the catechin compounds contained in the green tea was EGC(Epigallocatechin, C(catechin), EC(Epicatechin), EGCG(Epigallocatechin Gallate) and ECG(Epicatechin Gallate). From the experimental results the mobile phase for isolating EGCG from the extract consisted of 0.1% acetic acid in water/acetonitrile, 87/13%(v/v). The flow rate of mobile phase was 1.0 $m\ell$/min, and UV wavelength was fixed at 280 nm. 121.3 mg of EGCG, higher than 98% of purity, was obtained from 5 g of dry green tea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.459-464
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• 2002

This experiment was conducted to know the changes of bioactive component content in four-year-old peony (Paeonia lactiflora Pall.) root with various drying methods such as room temperature drying, $50^{\circ}C$ heat-air drying, room temperature drying after $80^{\circ}C$ boiling water treatment and freeze drying, and to establish the optimum drying method for high quality production of Paeoniae Radix. For this purpose, the contents of paeoniflorin, albiflorin and five phenolic compounds (gallic acid, benzoic acid, (+)-catechin, (-)-epicatechin and (+)-taxifolin 3-O-$\beta$-D-glucopyranoside) in peony root with different drying methods were analyzed by RP-HPLC. The contents of paeoniflorin, albiflorin and (+)-taxifolin 3-O-$\beta$-D-glucopyranoside at room temperature drying were higher than in the other drying methods and that of gallic acid at 8$0^{\circ}C$ boiling water treatment was the highest among that of all drying methods. In the case of freeze drying, the contents of (+)-catechin, benzoic acid and (-)-epicatechin were the highest among those of all drying methods. As increase of drying and treatment temperature, the contents of paeoniflorin, albiflorin, (+)-taxifolin 3-O-$\beta$-D-glucopyrano-side, (+)-catechin and benzoic acid were decreased.