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AIM To characterize the primary structure of recombinant L-asparaginase II product. METHODS The molecular weight of the protein was measured by pneumatically-assisted electrospray ionization mass spectrometry with flow injection mode. Subsequently, tryptic peptide mapping was performed by high performance liquid chromatography on a C8 column with tandem UV and MS detection. An easy-to-use and simple denaturation process with trichloroacetic acid was conducted prior to tryptic digest so as to release the digest resistance from the protein structure. The amino acid sequences of the tryptic peptides were elucidated based on their in-source collision-induced dissociation spectra. RESULTS The measured molecular mass was different from the theoretical value. Three amino acid variations were unambiguously detected along the peptide backbone derived from the gene-encoding sequence. CONCLUSION This paper revealed that LC/ESI/MS had provided a promising and robust technique in primary structure analysis and quality control of DNA-derived recombinant protein pharmaceuticals.
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AIM To explore the biotransformation of compound 7-(4-chlorbenzyl)-7,8,13,13a-tetrahydroberberine in the rabbit. METHODS Analyze the rabbit bile sample with HPLC, LC/MS and LC/NMR. RESULTS A metabolite and unchanged 7-(4-chlorbenzyl)-7,8,13,13a-tetrahydroberberine were found in the rabit bile, the metabolite was characterized and its structure was elucidated. CONCLUSION Compound 7-(4-chlorbenzyl)-7,8,13,13a-tetrahydroberberine is metabolized by demethylation at 10-OCH3 position.
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AIM To study the phase I metabolites of phenoprolamine hydrochloride (DDPH) in rat bile. METHODS DDPH was administered ip to bile duct-cannulated rats. Bile samples were collected before administration and up to 12 h after administration. After being treated with β-glucuronidase, the bile samples were purified and enriched with C-18 SPE columns, and then were analyzed by LC/DAD/MSD. The samples containing synthesized reference standards of DDPH metabolite 1-(2,6-dimethylphenoxy)-2-(3-methoxy-4-hydroxyphenylethylamino)-propane (M1), 1-(2,6-dimethyl-3-hydroxyphenoxy)-2-(3,4-methoxy-phenylethylamino)-propane (M2), 1-(2,6-dimethyl-4-hydroxyphenoxy)-2-(3,4-methoxyphenylethylamino)-propane (M3), 1-(2,6-dimethyl-4-hydroxyphenoxy)-2-(3-hydroxy-4-methoxyphenylethylamino)-propane (M4), 1-(2,6-dimethyl-3-hydroxyphenoxy)-2-(3-hydroxy-4-methoxyphenylethylamino)-propane (M5) and 1-(2,6-dimethyl-4-hydroxyphenoxy)-2-(3-methoxy-4-hydroxyphenylethylamino)-propane (M6) were analyzed by LC/DAD/MSD under identical conditions. RESULTS The retention times, UV spectra, molecular weights and production spectra (obtained by collision-induced dissociation)of the apparent ions of peak A, B, C, D, E and F in the total ion chromatogram of DDPH treated rat bile sample were consistent with those of M1, M2, M3, M5, M4 and M6, respectively. CONCLUSION M1, M2, M3, M4, M5 and M6 were identified as the phase I metabolites of DDPH in the rat.
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Object To establish the standardization and digit ization methods for gas chromatographic fingerprint chromatograms of the essenti al oil of Curcuma longa L. Methods A polynomial regression analysis technique was estab lished for the calculation and prediction of the gas chromatographic retention i ndices by using a series of normal aliphatic hydrocarbons as the reference stand ards. And it was used for the characterization of the features of the gas chroma tographic fingerprint spectra of the essential oil of C. longa. Results It was approved that retention indices of the gas chrom atographic fingerprint spectra obtained at a variety of conditions were stable and reliable with excellent reproducibility, and fairly good ruggedness. It was also much better than the relative retention time indices. Conclusion The fingerprint spectra standard established on t he multiple references basis are much more reasonable and useful for the practic al quality assurance and validation of Chinese herbals.
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Object To develop a new method for the determination of curcumol in essential oil from rhizoma Curcumae L.. Methods The contents of curcumol were determined by high performance capillary gas chromatography with sequential increase of temperature on a HEWLETT PACKARD 5890A gas chromatograph. Results The method can be used to determine curcumol with accuracy at a recovery of 101.4% and RSD of 0.40%. Conclusion The present study provided a satisfactory method for the determination of curcumol, and it was found that its contents in four different species (C. wenyujin, C. longa, C. aeruginose, and C. kwangsiensis) were markedly different.
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Objective To set up the reference standard of cyclovirobuxine D.Methods Thermal analysis,HPLC/MS,HPLC with terminal wavelength,HPLC with fluorescence derivation and with ultraviolet derivation,TLC and nonaqueous titration methods were applied to determine the content of cyclovirobuxine D control.Results Thermal analysis can not be used to analyse the purity of cyclovirobuxine D ,and HPLC/MS,HPLC with terminal wavelength,HPLC with fluorescence derivation and HPLC with ultraviolet derivation can obtain the same purity.Conclusion The methods used for the assay of cyclovirobuxine D control were practical.
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Objective:Chemical constituents of Sophora flavescems Ait. were studied by different extraction. Methods: Online HPLC/ESI/MS was used to study the different extraction. Results: numbers of alkaloids and flavone from Sophora flavescens Ait. were 9,8 and 12, respectively by means of chloroform strong aqua , water , and water methanol extraction. Conclusions: For the first time, we studied extraction of Sophora flavescems Ait by HPLC MS. This provided basic for study on fingerprints of Sophora flavescems Ait..