Dr Han Quanbin, Assistant Professor, Dr Chen Hubiao, Associate professor and Dr Xu Jun, Senior Research Assistant of the Teaching and Research Division of the School of Chinese Medicine, have invented a convenient and low-cost method to efficiently authenticate the valuable body strengthening Chinese herbal medicine Tiepi Shihu (Dendrobium officinale Kimura et Migo). The novel authentication method has been granted a patent by the United States Patent and Trademark Office and is being used by a Chinese medicines company in Hong Kong.
Tiepi Shihu is the dried stems of Dendrobium officinale Kimura et Migo, the rarest and most expensive species of Shihu. Tiepi Shihu nourishes the stomach, supplements body fluids, helps tonify yin, clears heat and strengthens the immune system. Due to its scarcity, the Tiepi Shihu found in the market may be mixed with other species of Shihu or may even be counterfeit.
Shihu goes through a process of drying and twisting before being sold. The dried rolls make it impossible to distinguish Tiepi Shihu from other Shihu species solely by appearance. To differentiate Tiepi Shihu from other species, the industry relies on experts, DNA bar-coding or microscopic identification. Nonetheless, DNA bar-coding is costly while microscopic identification has to be conducted by professionals and both methods cannot determine the content of active substances. Moreover, the established chemical methods cannot differentiate Dendrobium officinale from adulterants.
The research team conducted a study on the polysaccharide of Tiepi Shihu and other Shihu species. An identical and unique polysaccharide was discovered in all samples of Tiepi Shihu while it was not obviously found in the samples of other Shihu species. The result of the study reveals that this unique polysaccharide can serve as a marker to distinguish Tiepi Shihu from other species of Shihu quickly and effectively. The result of the study was published in international academic journal Analytical and Bioanalytical Chemistry in October 2014 (http://link.springer.com/article/10.1007%2Fs00216-014-8060-9).
This authentication method enables qualitative and quantitative analysis suitable for commercial use, particularly for Chinese medicines proprietors. The invention has been granted a patent by the United States Patent and Trademark Office and a patent application has been submitted to the State Intellectual Property Office of Mainland China.
Dr Han Quanbin (centre), Dr Chen Hubiao (left) and Dr Xu Jun obtain a US patent for their new method for authenticating Chinese herbal medicine Tiepi Shihu
Tiepi Shihu (left) is hardly distinguishable from other Shihu species