A quick and simple method can authenticate plants used in Chinese medicine, distinguishing genuine from counterfeit, wild from cultivated, and the plant’s geographical origin.
Developed by the Food Safety and Technology Research Centre at The Hong Kong Polytechnic University (PolyU) (PolyU), the approach uses direct ionization mass spectrometry to detect compounds in a plant sample.
A team, led by analytical chemist Yao Zhongping, used the approach on two of China’s most popular traditional medicines: Ganoderma lucidum, a mushroom commonly known as lingzhi; and Gastrodiae Rhizoma, a tuber from an orchid plant, commonly known as tianma.
A sample from each plant was loaded with chemical solvents. A high voltage was applied to the sample, leading to the formation of an aerosol-like spray that was analysed using mass spectrometry. The technique successfully identified the major active components in each plant, distinguishing genuine samples from counterfeit ones. A commonly used dataset analytical tool, called principal component analysis, was then used to differentiate wild from cultivated types, and identify the plants’ geographical origins.
Lingzhi and tianma are both used to treat a wide variety of diseases. There are approximately 80 lingzhi species, but only two of them, known as chizhi and zizhi, are described in China’s official compendium of drugs, “The Pharmacopoeia of the People's Republic of China”. Some lingzhi species, which are similar in appearance to each other, are easily confused with the official types. Tianma can also be easily confused with two counterfeit species.
Wild lingzhi and tianma are very rare, so medicinal varieties are often obtained through cultivation. The wild types generally have higher contents of the major active components and thus a better curative value. Samples originating from different geographical locations vary in their components due to the different cultivation conditions.
Conventionally, a technique called fingerprint chromatography is used to comprehensively identify the chemical composition of Chinese traditional medicines. However, it is labour-intensive and time-consuming, with the sample preparation and separating processes taking several hours.
PolyU’s method is simple, takes only ten minutes, and has the potential to analyse other traditional medicines. The researchers therefore expect it to have a positive impact on the Chinese traditional medicine industry.
The research findings were published in the journal Analytica Chimica Acta.
For further information, contact:
Associate Professor Yao Zhongping
Food Safety and Technology Research Centre
The Hong Kong Polytechnic University (PolyU)
E-mail: [email protected]