Optimization of extraction and determination of emodin from Polygonum cuspidatum Sieb. et Zucc. products by HPLC-DAD

Abstract

A uniform experimental design procedure was used to investigate the effects of some operating parameters on the extraction of emodin from Polygonum cuspidatum Sieb. et Zucc. products. Variables tested were volume ratio of material to solvent, size of material, extraction time and temperature and composition of extraction solvent (mixtures of acetone-water). Each variable was tested at seven levels; 7 experiments were performed in random order. Analyses of the extracts were performed by high-performance liquid chromatography with diode array detection(HPLC-DAD). Analytical responses were processed by using a forward regression analysis, in order to find polynomial function describing the relationship between variables and responses. For all the analytes the experimental conditions for providing the highest extraction yield inside the experimental domain considered were found. Finally, a simple, rapid and accurate analytical method was developed for the determination of emodin by high performance liquid chromatography. The separation is achieved within 25 min on an ODS column using methanol and water as gradient mobiles. Emodin can be quantified by using external standard method detecting at 436 nm. Good linearity is obtained with correlation coefficient exceeding 0.9986 and the detection limit and the quantification limit are 1.53 and 3.23 mg/L respectively. This method shows good reproducibility for the quantification of the emodin with intra-day and inter-day relative standard deviation less than 2.3% and 5.6% respectively. Under optimized extraction conditions, the recovery of the standard is 96.5%. The validated method is successfully applied to quantify the emodin in seven Polygonum cuspidatum sieb. Et zucc. products, which provided an idea for the pre-treatment of determination of active compounds in traditional Chinese medicines.

Keywords

Polygonum cuspidatum Sieb. et Zucc. / emodin / HPLC-DAD / extraction / quantification / Uniform design

References

[1] LiaoX.-y., TangX.-d., ZengF.-bo.. Anti-tumor pharmacology study of emdin in P. cuspidatum[J]. Chin Hosp Pharm J, 1988, 8(5): 214

[2] WangY.-sheng.Pharmacology and application of traditional Chinese medicine[M], 1983, Beijing, People’s Medical Press

[3] China Pharmacopoeia Committee.Chinese Pharmacopoeia[M]. (Vol.1), 2000, Beijing, Chemical Industry Press

[4] YaoC.-y., LiuW.-zhe.. Seasonal change of anthraquinone in vegetative organs of Polygonum cuspidatum[J]. Acta Bot Boreal Occident Sin, 2005, 25(1): 179-182

[5] WangJ., XiaD.-l., AnZ.-zhao.. Research on the content measurement of polydation and emodin of huzhang tablet[J]. J Hunan Industry Polytechnic, 2003, 3(4): 13-14

[6] WanJ.-x., XuJ.-luan.. Determination of total anthraquinone in ethonal extract of Polygonum cuspidatum[J]. Chin J Modern Appl Pharm, 2004, 21(4): 284-285

[7] ZhongP.. Determination of emodin and physcion from Polygonum cuspidatum[J]. Henan Pharm Information, 2002, 10(10): 9-10

[8] YuanK., YangZ.-h., YinP.-h., et al.. The process choice of rhizome poizoma cuspidatum extracted substance and quality analysis[J]. Chin J Modern Appl Pharm, 2000, 17(6): 444-446

[9] JiangH.-r., ZhuH., HuangH.-x., et al.. Effects of processing on piceid and emodin in Polygonum cuspidatum[J]. Chin Traditional and Herb Drug, 2003, 34(5): 412-415

[10] LiuX.-xi., HuanJ.. Determination of emodin in Fufang-huzhangqudu capsule[J]. Traditional Chin Med, 2003, 19(3): 57-58

[11] YangS.-xi.. Determination of emodin in Jinhubaogan granule by TLC[J]. China Pharmacist, 2005, 8(2): 138-139

[12] LiY., LiuH., JiX., et al.. Optimized separation of pharmacologically active anthraquinones in Rhubarb by capillary electrochromatography [J]. Electrophoresis, 2000, 21(15): 3109-3115

[13] LiW., ChanC. L., LuengH. W.. Liquid chromatography-atmospheric pressure chemical ionization mass spectrometry as a tool for the characterization of anthraquinone derivatives from Chinese herbal medicine[J]. J Pharm Pharmacol, 2000, 52(6): 723-729

[14] WengW. C., SheuS. J.. Separation of anthraquinones by capillary electrophoresis and high-performance liquid chromatography[J]. J High Resol Chromatogr, 2000, 23(2): 143-148

[15] SheuS. J., ChenH. R.. Simultaneous determination of twelve constituents of I-tzu-tang, a Chinese herbal preparation, by high-performance liquid chromatography and capillary electrophoresis[J]. J Chromatogr, 1995, 704(1): 141-148

[16] OkamuraN., AsaiM., HineN., et al.. High-performance liquid chromatographic determination of phenolic compounds in Aloe species[J]. J Chromatogr A, 1996, 746(2): 225-231

[17] SheuS. J., LuC. F.. Determination of eight constitutes of Hsiao-cheng-chi-tang by high-performance liquid chromatography[J]. J Chromatogr A, 1995, 704(2): 518-523

[18] TóthZ. A., RaatikainenO., NaaranlahtiT., et al.. Isolation and determination of alizarin in cell cultures of Rubia tinctorum and emodin in Dermocybe sanguinea using solid-phase extraction and high-performance liquid chromatography[J]. J Chromatogr, 1993, 630(2): 423-428

[19] FangK. T., WangY.Number theoretic methods in statistics[M], 1994, London, Chapman & Hall

[20] FangK.-t., MaC.-xing.Orthogonal and uniform experiment design[M], 2000, Hongkong, Hongkong Baptist University

[21] WanJ.-x., XuJ.-l., ZhuX.-yan.. Determination of emodin in Polygonum cuspidatum[J]. Chin J Exper Traditional Med Formulae, 2005, 11(3): 17-18