Objective: This study aimed to determine and quantify the presence of the active components in Thai propolis extracts using high performance liquid chromatography (HPLC). Moreover, the anti-caries potential of Thai propolis extract and its active ingredients were tested. Methods: Fifty milligrams of Thai propolis were extracted using either 100%, 90%, 80%, or 70% ethanol and subsequently analyzed using HPLC with a mobile phase gradient system of 10-100% acetonitrile in 0.05% aqueous ortho-phosphoric acid, flow rate of 0.8 mL/min, and detection wavelength of 280 nm. Varying concentrations of Thai propolis extracts as well as four active ingredients were subjected to agar well diffusion test against the growth of Streptococcus mutans (S. mutans) or Lactobacillus caseii (L. caseii). Results: The concentrations of the four active ingredients: vicenin-2, vitexin, apigenin, and cinnamic acid, were significantly affected by ethanolic concentrations. The chromatographic peaks of all active ingredients from 70% and 80% ethanolic extracts appeared more defined, as compared to those which used higher concentrations of ethanol for extraction. Except for the absolute ethanolic extract, all of the examined propolis extracts, as well as its active ingredients inhibited both S. mutans and L. caseii. Conclusions Thai propolis extracts contain vicenin-2, vitexin, apigenin, and cinnamic acid as part of its active ingredients. These were found to be significantly affected by the increase in ethanol during its extraction. The presence of these active ingredients might have contributed to the anti-caries potential of Thai propolis extracts.
flavonoids ; chromatography, high performance liquid

Objective To develop a reversed-phase high-performance liquid chromatography(RP-HPLC) method for the determination of residual phenylmethanesulfonyl fluoride(PMSF) content in recombinant virus-like particle(VLP) vaccine stock solution,and to verify the method for the determination of PMSF residues in recombinant VLP vaccine stock solution.Methods A RP-HPLC method for the determination of PMSF residues was developed by screening detection wavelength,flow rate,injection amount and chromatographic column.The specificity,linearity and range,limit of quantitation(LOQ),limit of detection(LOD),accuracy,precision and durability of the method were verified.The developed method was used to detect PMSF residues in three batches of recombinant hepatitis E vaccine stock solution.Results The RP-HPLC method was developed,with ChromCore 300 C18(4.6 mm × 250 mm,5 μm) as the chromatographic column at the column temperature of 25 ℃,the detection wavelength of 210 nm,the injection amount of 100 μL,0.1% trifluoroacetic acid(TFA)/water and0.1% TFA/acetonitrile as mobile phase at a flow rate of 1 mL/min,and the detection time of 18 min.The absorption peaks of PMSF control and vaccine stock solution containing PMSF appeared around 5.0 min,while the vaccine stock solution and stock solution buffer showed no absorption peak.There was a good linear relationship between the concentration of PMSF control and peak area in the range of 0-5.0 μg/mL,with R~2 of 0.999.The LOQ and LOD of this method was 0.250 μg/mL and 0.125 μg/mL,respectively.The recovery rates of PMSF control with high,medium and low concentrations were all between 90% and 110%.The relative standard deviations(RSDs) of retention time,peak height and peak area for the determination of instrument repeatability,sample repeatability and intermediate precision were all less than 5%.The RSDs of retention time,peak height and peak area were all less than 5% under the TFA concentration of 0.09%,0.1% and 0.11% at column temperature of 20,25 and 30 ℃.PMSF was not detected in the three batches of recombinant hepatitis E vaccine stock solution.Conclusion The developed RP-HPLC method has good specificity,linearity and durability,high accuracy and precision,and can be used to detect residual PMSF content in recombinant VLP vaccine stock solution.
Phenylmethanesulfonyl fluoride(PMSF) ; Reversed-phase high-performance liquid chromatography(RP-HPLC) ; Virus-like particle(VLP) vaccine

BACKGROUND: We evaluated the performance of the TOSOH glycohemoglobin analyzer HLC-723GHb V A1c 2.2TM (TOSOH Corp. Kyoto, Japan), a recently introduced automated hemoglobin A1c (HbA1c) analyzer using high performance liquid chromatography (HPLC) method without sample pretreatment. METHODS: The performance characteristics evaluated were precision, linearity, comparison with VARIANTTM (Bio-Rad, Germany) and throughput following NCCLS evaluation protocols (EP5-T2, EP6-P, and EP9-T). RESULTS: The within-run and between-day CV's were 0.910 and 1.328 for low level (6.2%), 1.214 and 1.460 for middle level (8.5%), and 0.789 and 1.449 for high level (10.7%), respectively. We found the perfect linearity of HbA1c (%) from 6.5 to 10.2 (r2=0.9995). Comparison studies between A1c 2.2 and VARIANTTM yielded the following correlation equations; A1c 2.2TM = 0.9915 (VARIANTTM) + 0.1198 %HbA1c (r=0.9936, P < 0.0001). Throughput was 28.0 tests per hour for A1c 2.2TM compared with 15.2 tests for VARIANTTM, which were determined including red blood cell lysis time before sample loading for VARIANTTM. A1c 2.2TM did not need sample pretreatment. CONCLUSIONS: With the above results, A1c 2.2TM shows acceptable performance and is suitable for routine use in the clinical laboratory.
Chromatography, High Pressure Liquid ; Chromatography, Liquid ; Erythrocytes

Amitriptylin hydrochloride is used as the internal standard in place of desipramine hydrochloride to determine the amount of imipramine hydrochloride by HPLC method. Results: Amitriptylin have the same structure as imipramin and the resolution degree between amitriptylin and imipramin is 1.8 while resolution degree between iminodibenzyl and imipramin is very high (R=10.7) because molecule structure of iminodibenzyl do not have branch-circuit. The suitability of chromatographic system through coefficient got high stable results with RSD<1.0%. Amitryptilin hydrochloride can be used as the internal standard in place of desipramine hydrochloride if necessary to test splitting degree in determination of imipramine hydrochloride
Imipramine ; Chromatography ; High Pressure Liquid

System suitability tests are an integral part of liquid chromatographic technique. They are used to verify the resolution (R) and reproducibility of the analysis to be done. HPLC method for assaying the related substances test of Cefaclor in raw material as well as in pharmaceutical dosage forms introduced to some pharmacopoeia such as EP, USP need to use Delta- 3 cefaclor as the internal standard to verify the suitability of chromatographic system. In case of lacking it to use, Cephalexin can be used as the internal standard in place of Delta-3 cefaclor. cell
Chromatography, High Pressure Liquid ; Cefaclor

This project is to study chemical compositions from the stems of Herpetospermum pedunculosum. Twenty-two compounds were isolated from the 70% acetone extract of the stems of H. pedunculosum by column chromatography on Sephadex LH-20, semi-preparative HPLC and preparative TLC. Their structures were elucidated by their physicochemical properties and spectroscopic data as N-benzyltyramine(1), α-spinasterol(2),(2S)-1-O-heptatriacontanoyl glycerol(3), 5,7-dihydroxychromanone(4), methyl 2β,3β-dihydroxy-D:C-friedoolean-8-en-29-oate(5), p-hydroxy benzyl alcohol(6), p-hydroxybenzoate(7), p-hydroxy cinnamic acid(8), 1H-indol-3-carboxylic acid(9), rhodiocyanoside B(10), rhodiolgin(11), rhodiosin(12), 9,12,13-trihydroxy-10(E)-octadecenoic acid(13), cylo-(Tyr-Leu)(14), matteflavoside A(15), loliolide(16), 1H-indol-3-carboxaldehyde(17),(+)-dehydrovomifoliol(18), 3-hydroxy-5α,6α-epoxy-β-ionone(19), 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxy-1-propen-1-yl)-2-methoxyphenoxy]-1-propanone(20), 7-en-nonadecanoic acid monoglyceride(21), vanillic acid(22). Compound 1 is a new natural product, while compounds 3-15 were isolated from this plant for the first time.
Chromatography, High Pressure Liquid ; Cucurbitaceae

This work was launched to study on the chemical constituents from Euphorbia thymifolia. Thirteen compounds were isolated from the 95% ethanol extract of the aerial parts of E. thymifolia by column chromatographies on silica gel, Sephadex LH-20, MCI, and ODS, and preparative HPLC, including two thymol derivatives(1-2), four alkaloids(3-6), five isocoumarins(7-11), together with two ellagic acids(12-13). All the compounds are listed as follows:(Z)-8,9-dehydro-9,10-diisobutyryloxythymol(1), 8-hydro-xy-9,10-diisobutyryloxythymol(2), N-(N-benzoyl-L-phenylalanyl)-L-phenylalanol(3), aurantiamide acetate(4), 1-carboethoxy-β-carboline(5), isoechinulin A(6), ethyl brevifolincarboxylate(7), euphorhirtin B(8), 4,5-didehydro chebulic acid triethyl ester(9), euphorhirtin G(10), pomegranatate(11), 3,3',4'-tri-O-methylellagic acid(12), 3,3'-di-O-methylellagic acid(13). Compound 1 is a new compound. Except for compound 4, the others were isolated from this plant for the first time. All the compounds were screened for anti-neuroinflammatory activity in vitro, and compounds 1-3 and 7 showed significant activity with IC_(50) values of 0.19,12.93,7.29,25.4 μmol·L~(-1).
Chromatography, High Pressure Liquid ; Euphorbia

OBJECTIVES

The aim of this study is to establish a Reversed Phase – High Performance Liquid Chromatographic (RP-HPLC) method for the quantification of Rhein from Cassia fistula L. leaves.

A Shimadzu system equipped with a C18 Column (150 x 4.6 mm, 5 μm) with an isocratic elution of Acetonitrile (solvent A) and 0.1% trifluoroacetic acid aqueous solution (solvent B) (Merck, 1.08178.0050) with a 55:45 ratio, respectively and a flow rate of 1.0 mL/min and sample injection of 10 μL detection was done at 230 nm. Standard solution of Rhein (Chengdu Biopurify) was prepared for method development. This study was validated using the guidelines set under “ICH Topic Q2 R2 or the Validation of Analytical Procedures”. Procedures for linearity, precision, accuracy, limit of detection, and limit of quantitation were performed.

The retention time of Rhein standard was determined at 5.10 minutes. LOD and LOQ were determined to be 1.278 mcg/mL and 3.872 mcg/mL, respectively with good linearity (R2 ≥0.996) with a linear range of 2.5-20 ug/mL of the Rhein standard. The accuracy of the method was determined based on % recovery method and ranged from 94.75%-100.32% (intraday, n=3) with %RSD of 0.71. The intraday precision %RSD was 2.92 (n=6) while interday precision %RSD was 3.75 (n=3). The method was able to check the Rhein quantity among 10 samples of Cassia fistula L. leaves from different locations in the Philippines.

The method was found to be sensitive and accurate for the quantification of Rhein. The method was found to be useful for the quantification of the amount of Rhein and can be used as a Quality Control tool for the assessment of Cassia fistula.

Objectives: The aim of this study is to establish a Reversed Phase – High Performance Liquid Chromatographic (RP-HPLC) method for the quantification of Rhein from Cassia fistula L. leaves. Methods: A Shimadzu system equipped with a C18 Column (150 x 4.6 mm, 5 μm) with an isocratic elution of Acetonitrile (solvent A) and 0.1% trifluoroacetic acid aqueous solution (solvent B) (Merck, 1.08178.0050) with a 55:45 ratio, respectively and a flow rate of 1.0 mL/min and sample injection of 10 μL detection was done at 230 nm. Standard solution of Rhein (Chengdu Biopurify) was prepared for method development. This study was validated using the guidelines set under “ICH Topic Q2 R2 or the Validation of Analytical Procedures”. Procedures for linearity, precision, accuracy, limit of detection, and limit of quantitation were performed. Results: The retention time of Rhein standard was determined at 5.10 minutes. LOD and LOQ were determined to be 1.278 mcg/mL and 3.872 mcg/mL, respectively with good linearity (R2 ≥0.996) with a linear range of 2.5-20 ug/mL of the Rhein standard. The accuracy of the method was determined based on % recovery method and ranged from 94.75%-100.32% (intraday, n=3) with %RSD of 0.71. The intraday precision %RSD was 2.92 (n=6) while interday precision %RSD was 3.75 (n=3). The method was able to check the Rhein quantity among 10 samples of Cassia fistula L. leaves from different locations in the Philippines. Conclusion The method was found to be sensitive and accurate for the quantification of Rhein. The method was found to be useful for the quantification of the amount of Rhein and can be used as a Quality Control tool for the assessment of Cassia fistula.
Cassia ; Chromatography, High Pressure Liquid

BACKGROUND: Hemoglobin A1c (HbA1c) is widely used for the monitoring of glycemic control. A wide variety of different analytical methods is currently used by clinical laboratories. We performed this study to evaluate the newest ion-exchange high-performance liquid chromatography system, the HLC-723 G7 (Tosoh Corporation, Tokyo, Japan) automated glycohemoglobin analyzer. METHODS: HLC-723 G7 was evaluated for linearity, precision, comparison of method, and speed. HLC-723 G7 was compared with three analyzers including HLC-723 GHb V A1c 2.2, Variant II, and Cobas Integra 800. RESULTS: HLC-723 G7 showed within-run and total imprecision (CVs) of less than 2.5% and excellent linearity to at least 13.0%. HbA1c values obtained from HLC-723 G7 were strongly correlated with those from HLC-723 GHb V A1c 2.2. Comparison with two other methods showed a good correlation but revealed calibration differences throughout the analytical range. HLC-723 G7 required no sample preparation and showed a fast analytical time of 1.6 min. CONCLUSIONS: HLC-723 G7 provides high throughput and excellent precision. However, HbA1c values can differ considerably with different methods or instruments. Therefore, we should be aware of the potential problem in switching the HbA1c testing method
Calibration ; Chromatography, High Pressure Liquid ; Chromatography, Liquid ; Diabetes Mellitus