title: Identification of powdered Chinese herbal medicines by fluorescence microscopy, Part 1: Fluorescent characteristics of mechanical tissues, conducting tissues, and ergastic substances.
abstract: The light microscope has been successfully used in identification of Chinese herbal medicines (CHMs) for more than a century. However, positive identification is not always possible. Given the popularity of fluorescence microscopy in bioanalysis, researchers dedicated to finding new ways to identify CHMs more effectively are now turning to fluorescence microscopy for authentication purposes. Some studies on distinguishing confused species from the same genus and on exploring distributions of chemicals in tissues of CHMs by fluorescence microscopy have been reported; however, no systematic investigations on fluorescent characteristics of powdered CHMs have been reported. Here, 46 samples of 16 CHMs were investigated. Specifically, the mechanical tissues including stone cells and fibers, the conducting tissues including three types of vessels, and ergastic substances including crystals of calcium oxalate and secretions, in various powdered CHMs were investigated by both light microscope and fluorescence microscope. The results showed many microscopic features emit fluorescence that makes them easily observed, even against complex backgrounds. Under the fluorescence microscope, different microscopic features from the same powdered CHM or some same features from different powdered CHMs emitted the different fluorescence, making this information very helpful for the authentication of CHMs in powder form. Moreover, secretions with unique chemical profiles from different powdered CHMs showed different fluorescent characteristics. Hence, fluorescence microscopy could be a useful additional method for the authentication of powdered CHMs if the fluorescent characteristics of specific CHMs are known.
authors.affiliation: School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong; Key Laboratory of Modern Chinese Medicines, Department of Pharmacognosy, China Pharmaceutical University, Nanjing, People's Republic of China.
authors.forename: Ya-Qiong
authors.initials: YQ
authors.lastname: Wang
authors.forename: Zhi-Tao
authors.initials: ZT
authors.lastname: Liang
authors.forename: Qin
authors.initials: Q
authors.lastname: Li
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
authors.forename: Hu-Biao
authors.initials: HB
authors.lastname: Chen
authors.forename: Zhong-Zhen
authors.initials: ZZ
authors.lastname: Zhao
authors.forename: Ping
authors.initials: P
authors.lastname: Li
mesh_terms: D001114:Areca / Q000009:adverse effects; D027761:Asparagus Plant / Q000009:adverse effects; D002129:Calcium Oxalate / Q000737:chemistry / Q000302:isolation & purification; D004365:Drugs, Chinese Herbal / Q000009:adverse effects / Q000032:analysis / Q000737:chemistry*; D004721:Endoplasmic Reticulum / Q000187:drug effects; D004727:Endothelium / Q000187:drug effects*; D006801:Humans; D031660:Jasminum / Q000009:adverse effects; D008856:Microscopy, Fluorescence / Q000379:methods*; D031441:Ophiopogon / Q000009:adverse effects; D027861:Prunus / Q000009:adverse effects; D032266:Scrophularia / Q000009:adverse effects
chemical_list: D004365:Drugs, Chinese Herbal; D002129:Calcium Oxalate