{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,8]],"date-time":"2026-03-08T12:08:31Z","timestamp":1772971711230,"version":"3.50.1"},"reference-count":47,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2023,7,10]],"date-time":"2023-07-10T00:00:00Z","timestamp":1688947200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Kaiser Pharmaceutical Co. Ltd."}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>A previous 1H-NMR method allowed the quantification of ephedrine alkaloids; however, there were some disadvantages. The cyclized derivatives resulted from the impurities of diethyl ether were identified and benzene was selected as the better extraction solvent. The locations of ephedrine alkaloids were confirmed with 2D NMR. Therefore, a specific 1H-NMR method has been modified for the quantification of ephedrine alkaloids. Accordingly, twenty Ephedrae Herba samples could be classified into three classes: (I) E. sinica-like species; (II) E. intermedia-like species; (III) others (lower alkaloid contents). The results indicated that ephedrine and pseudoephedrine are the major alkaloids in Ephedra plants, but the concentrations vary greatly determined by the plant species and the collection locations.<\/jats:p>","DOI":"10.3390\/ijms241411272","type":"journal-article","created":{"date-parts":[[2023,7,11]],"date-time":"2023-07-11T01:40:02Z","timestamp":1689039602000},"page":"11272","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["A Modified 1H-NMR Quantification Method of Ephedrine Alkaloids in Ephedrae Herba Samples"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1706-1139","authenticated-orcid":false,"given":"Yue-Chiun","family":"Li","sequence":"first","affiliation":[{"name":"School of Pharmacy, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chia-Hung","family":"Wu","sequence":"additional","affiliation":[{"name":"School of Post-Baccalaureate Chinese Medicine, China Medical University, Taichung 404, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thi Ha","family":"Le","sequence":"additional","affiliation":[{"name":"School of Pharmacy, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qingjun","family":"Yuan","sequence":"additional","affiliation":[{"name":"State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100010, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Luqi","family":"Huang","sequence":"additional","affiliation":[{"name":"State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100010, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Guo-Fen","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mei-Lin","family":"Yang","sequence":"additional","affiliation":[{"name":"School of Pharmacy, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sio-Hong","family":"Lam","sequence":"additional","affiliation":[{"name":"School of Pharmacy, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7666-2420","authenticated-orcid":false,"given":"Hsin-Yi","family":"Hung","sequence":"additional","affiliation":[{"name":"School of Pharmacy, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Handong","family":"Sun","sequence":"additional","affiliation":[{"name":"Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yi-Hung","family":"Wu","sequence":"additional","affiliation":[{"name":"Hsinhua Forest Station, The Experimental Forest Management Office, National Chung-Hsing University, Taichung 402, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3019-1138","authenticated-orcid":false,"given":"Ping-Chung","family":"Kuo","sequence":"additional","affiliation":[{"name":"School of Pharmacy, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tian-Shung","family":"Wu","sequence":"additional","affiliation":[{"name":"School of Pharmacy, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Gonz\u00e1lez-Ju\u00e1rez, D.E., Escobedo-Moratilla, A., Flores, J., Hidalgo-Figueroa, S., Mart\u00ednez-Tag\u00fce\u00f1a, N., Morales-Jim\u00e9nez, J., Mu\u00f1iz-Ram\u00edrez, A., Pastor-Palacios, G., P\u00e9rez-Miranda, S., and Ram\u00edrez-Hern\u00e1ndez, A. 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