Short communication
Simultaneous determination of key bioactive components in Hedyotis diffusa by capillary electrophoresis

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Abstract

A capillary zone electrophoresis (CZE) method based on systematic one-variable-at-a time approach was developed for the analysis of four important bioactive components (geniposidic acid, ursolic acid, quercetin and p-coumaric acid) in the extract of Hedyotis diffusa (HD). Separations were carried out in a fused-silica capillary tube with peak detection at 214 nm. Good separation was achieved using a 20 mM borate buffer containing 5% acetonitrile as organic modifier and pH adjusted to 10.0. Operating voltage was 15 kV and temperature was maintained at 25 °C while hydrodynamic injection was 5 s. A good linearity, with correlation coefficients in the ranges of 0.997–0.999 was obtained in the calibration curves of each standard. Relative standard deviation (R.S.D.) of migration time was between 0.32 and 0.70% and deviation of corrected peak area was between 8.84 and 11.99%. These results indicate that this method could be used for rapid and simultaneous analysis of the bioactive components in HD and other herbal products.

Introduction

Traditional Chinese medicines have been used to treat human diseases in China for centuries. In the last three decades, pharmaceutical explorations of bioactive components in traditional medicines have attracted lots of scientific attention [1]. Because most traditional Chinese medicines consist of complex constituents, a proper analytical technique for their rapid and simultaneous analysis is urgently required [2].

Hedyotis diffusa (HD), also called ‘Ped-Hue-Juwa-Chji-Cao’ in Chinese, is a notable annual herb widely distributed in northeast Asia. The herb has been commonly used for the treatment of various diseases, including rheumatism, arthritis, appendicitis, sore throat, urethral infection, contusions and for eliminating the invasion and extension of malignancies [3], [4], [5]. Recent study by Gupta et al. [6] found that aqueous extract of HD effectively inhibited the proliferation of eight cancer cell lines and induced significant increase of apoptosis; yet exhibited minimum toxic effect on normal pancreatic cells. There were other reports indicating that methanol extracts of this herb exerted antimicrobial activities and antifungal activities [7].

Because this herb shows a lot of beneficial effect to human health, it has been used to augment the therapeutic effects of other herbs. Whatever the uses, effectiveness of treatment for a disease is dose dependent. Therefore, it is necessary to determine the amount of bioactive component in a pharmaceutical product. It has been demonstrated that the major active components in HD are ursolic acid, oleanolic acid, p-coumaric acid, geniposidic acid and quercetin [8], [9], [10]. These components represent different chemical nature and can be used as quality markers for HD. However, there is no suitable method currently available for simultaneous determination of these components in the herb. A simple, reliable and reproducible method for the analysis of bioactive components in HD is vital no matter whether for pharmacokinetic studies or for quality control of the herb.

Capillary electrophoresis (CE) has become one of the most popular methods for qualitative and quantitative analysis of herbal products. The method is suitable for simultaneous analysis of mixed compounds and offers advantages of excellent separation in terms of efficiency and resolution of analysis. As there is no report on the determination of the major active substances in HD by CE, this paper aims to describe a CZE method for quick and simultaneous determination of four key bioactive components of different chemical nature in the herb.

Section snippets

Apparatus

A capillary electrophoretic system (Beckman P/ACE 5000) purchased from Beckman Instruments (Fullerton, CA, USA) was used throughout the whole study. The system and the method of data analysis were the same as previously described [11]. The CE system was operated in a normal mode with the cathode at the detector end. Prior to running any standard or sample solutions through the system, the capillary was conditioned with 0.1 M NaOH for 15 min followed by Milli-Q water for 15 min as described

Method development

Earlier work from our group demonstrated that successful CE separation of a mixture of eleven bioactive components required optimization of the separation condition that involves proper use of pH, buffer concentration, right choice of organic solvent and surfactant concentration [13]. Although three out of the four components described here had already been covered, the method was not suitable for simultaneous analysis of all four bioactive components in HD. Hence, a specific condition for

Conclusions

In conclusion, an analytical method based on capillary zone electrophoresis for rapid and simultaneous determination of four important bioactive components in HD has been successfully established in this study. The method is simple, efficient, sensitive, accurate and reliable. It can be used for quantitative study and for quality control of the herb by means of analyzing the bioactive components.

Acknowledgements

The author would like to acknowledge the financial support from Pharmaceutical and Chemical Technology Center Ltd to S.H. Cheung and W.P. Lai. Financial support from HealthWorks Group Holdings Ltd. (Hong Kong SAR, China) to purchase bioactive markers is also acknowledged.

References (18)

  • T.I. Ho et al.

    Phytochemistry

    (1986)
  • H.Y. Cheung et al.

    J. Chromatogr. A

    (2001)
  • H.Y. Cheung et al.

    J. Chromatogr. A

    (2003)
  • L.N. Li

    Pure Appl. Chem.

    (1998)
  • D.J. Hood, S.N.W. Ng, S.C.K. Kong, H.Y. Cheung, Hong Kong Pharm. J. 9 (2000)...
  • S. Takagi et al.

    Shoyakugaku Zasshi

    (1982)
  • W.S. Kan

    Manual of Vegetable Drug in Taiwan

    (1978)
  • L.L.H. Liao et al.

    J. Formosan Med. Assoc.

    (1979)
  • S. Gupta et al.

    J. Herb. Pharmacother.

    (2004)
There are more references available in the full text version of this article.

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