Chem. Pharm. Bull. 53(11) 1484—1489 (2005)

materia medica (CMM) has always been a key issue for the rapid development of Chinese medicine. Among other analytical techniques, HPLC, capillary electrophoresis (CE), TLC, NMR and IR have been widely used in the quality evaluation of medicinal herbs. The rapid development of fingerprinting methods using these ranges of analytical tools for authentication and quality assessment of CMM has recently been accepted by the World Health Organization (WHO) as a strategy for the assessment of herbal medicines. Besides, it is also required by the Drug Administration Bureau of China as a quality assessment tool for standardizing all medicinal injections manufactured from traditional Chinese medicines and their raw materials. Among these techniques, GC-MS is commonly used for characterization and is a particularly useful approach in the identification of volatile organic compounds in CMM. Fresh H. cordata is the entire herb of fresh Houttuynia cordata THUNB., which is a well known traditionally used Chinese medicinal material in China and Japan and is listed in the Chinese Pharmacopoeia. It possesses a variety of pharmacological activities including anti-platelet aggregation, antibacterial, antitumor, antimicrobial, anti-inflammatory, immunomodulatory and recently, it has demonstrated considerable efficacy in anti-SARS. It was reported that H. cordata contained groups of such chemical components as flavones, fatty acids, essential oil and alkaloids. In modern pharmacological terms, a volatile oil is regarded as the major bioactive compound possessing antibacterial, antifungal, anti-histamine and anti-viral activities. The steam distillate of fresh H. cordata can inhibit herpes simplex virus type 1 (HSV-1), influenza virus, and human immunodeficiency virus type 1 (HIV-1). However, it is worth noting that the components of volatile oil are generally unstable and liable to decompose during the drying process. Besides, some previous related research has stated that variation in medicinal parts, production areas and processing methods are also influential factors affecting the therapeutic efficacy of herbs. In this regard, the present study seeks to develop a characteristic fingerprint of fresh H. cordata for authentication, with respect to the dry counterpart, and then apply it in quality assessment. Herb samples were analyzed with GC-MS. The chemical components were identified by matching against the standard mass spectral database of National Institute of Standards and Technology (NIST147, NIST27). A combination of mathematics and statistical approaches were then applied to study the relationship of the acquired chromatographic profiles. The Computer Aided Similarity Evaluation System is computer software recently developed by the Research Center of Modernization of Traditional Chinese Medicines (Central South University, Changsha, China), and is mainly applied in the similarity study of chromatographic and spectral patterns. In this study, this software was used to synchronize the chromatographic peaks and calculate the correlation coefficients between entire chromatographic profiles, and to do quantitative comparison among different samples, as well as to compute and generate the simulative mean chromatogram as a representative standard fingerprint chromatogram for a group of chromatograms. Besides, the relative retention time (RRT) and relative peak area (RPA) of each characteristic peak related to the reference peak were calculated for the quantitative expression of chemical properties in the chromatographic pattern of herbs. The generated data provided valuable insights into the application of the fingerprint in the analysis/quality control of herbs. In this study, a total of 31 H. cordata samples were analyzed (Table 1). Sixteen common chemical compounds were identified in the GC-MS fingerprint. A reproducible GC-MS fingerprint technique was developed for the authentication of fresh and dry herbs. The methodology was found to differentiate between fresh and drug herbs, as well as different portions of the herb.