An experimental study on identification of sulfur-fumigated Chinese medicinal materials (Codonopsis Radix and Ginseng Radix) by fluorescence microscopy
Year of Award
Master of Pharmaceutical Sciences in Chinese Medicine (MPharm)
School of Chinese Medicine.
China, Identification, Fluorescence microscopy, Materia medica, Vegetable, Medicinal plants
Background: SF processing has been firstly applied on the processing and storage of the rhizome of Dioscareapersimilis Prain et Burkill. in Wenxian country since 1900. Due to the simple, quick and low-cost characteristics of SF, it soon became a common postharvesting method for CMMs. However, recent studies showed that SF can either cause chemical changes to CMMs or affect human health. The awareness of identification of sulfur-fumigated CMMs is arisen. Comparing with chemical methods, FM is more simple and user-friendly to be established in authentication. Also, recent studies showed that different chemical profiles of CMMs can emit fluorescence differently. This research aimed to validate if FM was suitable for identification of sulfur-fumigated CMMs through using Codonopsis Radix and Ginseng Radix as examples. Method: 16 herbal samples were collected in different commercial market in different time, in which 6 of them was Codonopsis Radix and 8 of them was Ginseng Radix. Firstly, their chemical profiles of the samples were analyzed by UHPLC-QTOF-MS to make a chemical authentication. Then, their fluorescence characteristic were localized and captured on their transverse sections. Result: All the samples of Codonopsis Radix and 2 samples of Ginseng Radix were confirmed to be sulfur-fumigated as compounds sulfates or sulfites were detected. Investigated by fluorescence, herbal samples emitted blue and yellow fluorescence in different intensity under blue and green light filter. The fluorescence of groups of laticiferous tubes and resin canals were remarkable in Codonopsis Radix and Ginseng Radix respectively. Sulfur-fumigated samples showed similar characteristic to those raw samples. It was significant that samples of Codonopsis Radix emitted fluorescence differently even all of them were sulfur-fumigated. Conclusion: In the present study, samples with different growing condition, storage time and SF processing had some variation in their fluorescence characteristics. The result showed that fluorescence microscopy was not probable for identification of the sulfur-fumigated CMMs. The application of FM on the identification of sulfur-fumigated CMMs should be further investigated comprehensively. Key works: sulfur-fumigation; Codonopsis Radix; Ginseng Radix; authentication; fluorescence microscopy; UHPLC-QTOF-MS 背景：硫磺薰蒸中藥技術是在1900年由溫縣人民發明並最早記載於河南溫縣縣誌的。由於硫磺薰蒸技術擁有最高效，低成本，便於操控的優點，因此一直被藥農及中藥開發藥廠用於中藥防蟲及乾燥加工。但近年不少論文開始報道有關硫磺對中藥材的危害性，其中以硫磺薰蒸會影響中藥材內部的化學成分和藥理活性的報告最令人擔憂。礙於高效液相色譜法(HPLC)等化學檢測手段的複雜性，使用化學手段鑒別硫磺熏蒸藥材存在困難及難以普及。而近年實驗證明，中藥材裏不同的化學成分在熒光顯微鏡下會發放出不同熒光顔色。本研究以人參和黨參為例子，為應用熒光顯微鏡鑒別硫磺熏蒸中藥材，提供科學證據支持。 實驗方法：本研究採集了6個黨參及8個人參樣品進行分析。實驗首先以高效液相色譜-四極杆飛行時間串聯質譜(UHPLC-QTOF/MS)技術分析各樣品的化學成分用於鑒別樣品有否被硫磺熏蒸。然後各樣品先進行冷凍切割，並在熒光顯微鏡下進行橫切面觀察，從外到内觀察各特徵結構的熒光顔色，比較不同樣品的熒光差別。 結果：實驗結果顯示所有黨參樣品及2個白皮參樣品存在硫磺熏蒸后產生的硫酸鹽或亞硫酸鹽化合物，提示該樣品被硫磺熏蒸。所有樣品在熒光顯微鏡下都顯示不同程度的藍色及綠色熒光。儘管所有黨參樣品均被硫熏，但其顯示的熒光仍存在明顯差異，其中以樣品5和6最爲明顯。而被硫熏的人參樣品，其熒光則非常類似於非硫熏樣品。非硫熏的人參其熒光仍存在個體差異，其中2個樣品的熒光強度較其他為強及明顯。黨參内的乳管群及人參内的樹脂道，其熒光強度及顔色最爲突出。 結論：研究結果表明不同來源的樣品，其熒光特徵存在區別。熒光顯微鑑定技術不能有效鑒別市場上的黨參和人參是否經過硫磺熏蒸。熒光顯微鑑定硫磺熏蒸中藥方面的應用有待深入及系統探討。 關鍵詞：硫磺熏蒸；黨參；人參；熒光顯微鏡；中藥鑒別；高效液相色譜-四極杆飛行時間串聯質譜(UHPLC-QTOF/MS)
Chan, Martin Chun Wai, "An experimental study on identification of sulfur-fumigated Chinese medicinal materials (Codonopsis Radix and Ginseng Radix) by fluorescence microscopy" (2013). Open Access Theses and Dissertations. 2.
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