{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T19:53:15Z","timestamp":1788465195976,"version":"build-2803163510"},"reference-count":37,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,6,10]],"date-time":"2021-06-10T00:00:00Z","timestamp":1623283200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Apothekerstiftung Westfalen-Lippe","award":["Doctoral fellowship, no grant number"],"award-info":[{"award-number":["Doctoral fellowship, no grant number"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Malaria and human African trypanosomiasis (HAT; sleeping sickness) are life-threatening tropical diseases caused by protozoan parasites. Due to limited therapeutic options, there is a compelling need for new antiprotozoal agents. In a previous study, O-tigloylcyclovirobuxeine-B was recovered from a B. sempervirens L. (common box; Buxaceae) leaf extract by bioactivity-guided isolation. This nor-cycloartane alkaloid was identified as possessing strong and selective in vitro activity against the causative agent of malaria tropica, Plasmodium falciparum (Pf). The purpose of this study is the isolation of additional alkaloids from B. sempervirens L. to search for further related compounds with strong antiprotozoal activity. In conclusion, 25 alkaloids were obtained from B. sempervirens L., including eight new natural products and one compound first described for this plant. The structure elucidation was accomplished by UHPLC\/+ESI-QqTOF-MS\/MS and NMR spectroscopy. The isolated alkaloids were tested against Pf and Trypanosoma brucei rhodesiense (Tbr), the causative agent of East African sleeping sickness. To assess their selectivity, cytotoxicity against mammalian cells (L6 cell line) was tested as well. Several of the compounds displayed promising in vitro activity against the pathogens in a sub-micromolar range with concurrent high selectivity indices (SI). Consequently, various alkaloids from B. sempervirens L. have the potential to serve as a novel antiprotozoal lead structure.<\/jats:p>","DOI":"10.3390\/antibiotics10060696","type":"journal-article","created":{"date-parts":[[2021,6,10]],"date-time":"2021-06-10T13:31:39Z","timestamp":1623331899000},"page":"696","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Antiprotozoal Nor-Triterpene Alkaloids from Buxus sempervirens L."],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8654-5965","authenticated-orcid":false,"given":"Lara U.","family":"Szab\u00f3","sequence":"first","affiliation":[{"name":"Institute of Pharmaceutical Biology and Phytochemistry (IPBP), University of M\u00fcnster, PharmaCampus Corrensstra\u00dfe 48, D-48149 M\u00fcnster, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marcel","family":"Kaiser","sequence":"additional","affiliation":[{"name":"Swiss Tropical and Public Health Institute (Swiss TPH), Socinstrasse 57, CH-4051 Basel, Switzerland"},{"name":"University of Basel, Petersplatz 1, CH-4003 Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3122-1941","authenticated-orcid":false,"given":"Pascal","family":"M\u00e4ser","sequence":"additional","affiliation":[{"name":"Swiss Tropical and Public Health Institute (Swiss TPH), Socinstrasse 57, CH-4051 Basel, Switzerland"},{"name":"University of Basel, Petersplatz 1, CH-4003 Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2634-9705","authenticated-orcid":false,"given":"Thomas J.","family":"Schmidt","sequence":"additional","affiliation":[{"name":"Institute of Pharmaceutical Biology and Phytochemistry (IPBP), University of M\u00fcnster, PharmaCampus Corrensstra\u00dfe 48, D-48149 M\u00fcnster, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,6,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"270","DOI":"10.1016\/j.jep.2009.04.041","article-title":"Ethnopharmacological notes about ancient uses of medicinal plants in Tr\u00e1s-os-Montes (northern of Portugal)","volume":"124","author":"Neves","year":"2009","journal-title":"J. Ethnopharmacol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/0378-8741(85)90028-5","article-title":"Phytotherapy in the Valnerina Marche (Central Italy)","volume":"14","author":"Leporatti","year":"1985","journal-title":"J. Ethnopharmacol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"619","DOI":"10.1039\/a705715f","article-title":"Diterpenoid and steroidal alkaloids","volume":"16","author":"Choudhary","year":"1999","journal-title":"Nat. Prod. Rep."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Ata, A., and Andersh, B.J. (2008). Chapter 3 Buxus Steroidal Alkaloids: Chemistry and Biology, Academic Press. The Alkaloids: Chemistry and Biology.","DOI":"10.1016\/S1099-4831(08)00203-4"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"47","DOI":"10.2174\/157340711795163811","article-title":"Chemistry and Biological Activities of Buxus Alkaloids","volume":"7","author":"Yan","year":"2011","journal-title":"CBC"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"6184","DOI":"10.3390\/molecules19056184","article-title":"Antiprotozoal activity of Buxus sempervirens and activity-guided isolation of O-tigloylcyclovirobuxeine-B as the main constituent active against Plasmodium falciparum","volume":"19","author":"Althaus","year":"2014","journal-title":"Molecules"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"490","DOI":"10.1021\/acs.jnatprod.5b00874","article-title":"Identification of Compounds with Efficacy against Malaria Parasites from Common North American Plants","volume":"79","author":"Cai","year":"2016","journal-title":"J. Nat. Prod."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Flittner, D., Kaiser, M., M\u00e4ser, P., Lopes, N.P., and Schmidt, T.J. (2021). The Alkaloid-Enriched Fraction of Pachysandra terminalis (Buxaceae) Shows Prominent Activity against Trypanosoma brucei rhodesiense. Molecules, 26.","DOI":"10.3390\/molecules26030591"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Nnadi, C.O., Althaus, J.B., Nwodo, N.J., and Schmidt, T.J. (2018). A 3D-QSAR Study on the Antitrypanosomal and Cytotoxic Activities of Steroid Alkaloids by Comparative Molecular Field Analysis. Molecules, 23.","DOI":"10.20944\/preprints201804.0282.v1"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"4563","DOI":"10.1016\/S0040-4020(01)92557-8","article-title":"Buxus alkaloids\u2014XII","volume":"23","author":"Kupchan","year":"1967","journal-title":"Tetrahedron"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Szab\u00f3, L.U., and Schmidt, T.J. (2020). Target-Guided Isolation of O-tigloylcyclovirobuxeine -B from Buxus sempervirens L. by Centrifugal Partition Chromatography. Molecules, 25.","DOI":"10.3390\/molecules25204804"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"608","DOI":"10.1021\/jo01340a516","article-title":"Buxus Alkaloids. X. 1 The Isolation and Constitution of Cyclovirobuxeine-B","volume":"31","author":"Kupchan","year":"1966","journal-title":"J. Org. Chem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1035","DOI":"10.1016\/S0040-4039(00)90427-1","article-title":"Buxus alkaloids. Part, I. The structures of three new alkaloids, cyclomicrophylline-A., B., and C., from B. microphylla Sieb. et Zucc","volume":"5","author":"Nakano","year":"1964","journal-title":"Tetrahedron Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1021\/np50073a003","article-title":"Chemical Constituents of Buxus sempervirens","volume":"54","author":"Ahmed","year":"1991","journal-title":"J. Nat. Prod."},{"key":"ref_15","first-page":"4512","article-title":"Buxus alkaloids. IV. Isolation and structure elucidation of eight new alkaloids, cyclomicrophylline-A, -B, and -C, dihydrocyclomicrophylline-A and -F, cyclomicrophyllidine-A, dihydrocyclomicrophyllidine-A, and cyclomicrobuxine, from B. microphylla Sieb. et Zucc. var. suffruticosa Makino","volume":"1","author":"Nakano","year":"1965","journal-title":"J. Chem. Soc. Perkin Trans."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1007\/s00049-013-0134-1","article-title":"Composition of alkaloids in different box tree varieties and their uptake by the box tree moth Cydalima perspectalis","volume":"23","author":"Leuthardt","year":"2013","journal-title":"Chemoecology"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1039","DOI":"10.1002\/cbdv.200690102","article-title":"New cholinesterase-inhibiting triterpenoid alkaloids from Buxus hyrcana","volume":"3","author":"Choudhary","year":"2006","journal-title":"Chem. Biodivers."},{"key":"ref_18","first-page":"643","article-title":"Buxarin und Buxenon, zwei neue Alkaloide aus Buxus sempervirens L.","volume":"21","year":"1966","journal-title":"Die Pharm. Jahrg."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"173","DOI":"10.1055\/s-2006-962384","article-title":"Chemical Constituents of Buxus sempervirens","volume":"54","author":"Ahmed","year":"1988","journal-title":"Planta Med."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Nakano, T., Terao, S., and Saeki, Y. (1966). Buxus alkaloids. Part VII. The isolation and the constitutions of ten new alkaloids from the weak-base fractions of two species, B. microphylla Sieb. et Zucc. var. suffruticosa Makino and B. microphylla Sieb. et Zucc. var. suffruticosa Makino forma major Makino. J. Chem. Soc. C, 1412.","DOI":"10.1039\/j39660001412"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"783","DOI":"10.1021\/np50058a024","article-title":"Alkaloids from the Leaves of Buxus sempervirens","volume":"51","author":"Ahmed","year":"1988","journal-title":"J. Nat. Prod."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"976","DOI":"10.1021\/np970207e","article-title":"New steroidal alkaloids from Buxus longifolia","volume":"60","author":"Choudhary","year":"1997","journal-title":"J. Nat. Prod."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3579","DOI":"10.1016\/S0040-4039(01)99542-5","article-title":"Alkaloids from Buxus sempervirens L. V. Configuration of buxtauine and buxpiine","volume":"6","author":"Tomko","year":"1965","journal-title":"Tetrahedron Lett."},{"key":"ref_24","first-page":"174","article-title":"Buxus alkaloids. XIII. Alkaloids from Buxus sempervirens var. argentea Hort. ex. Steud","volume":"30","author":"Kuchkova","year":"1976","journal-title":"Chem. Zvesti"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2933","DOI":"10.1016\/0031-9422(92)83673-M","article-title":"Alkaloids from Buxus species","volume":"31","author":"Naz","year":"1992","journal-title":"Phytochemistry"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"951","DOI":"10.1016\/S0031-9422(00)00036-4","article-title":"Four steroidal alkaloids from the leaves of Buxus sempervirens","volume":"54","author":"Loru","year":"2000","journal-title":"Phytochemistry"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1002\/zfch.19730130411","article-title":"N-Benzoylbuxodienin-E und N-Benzoyl-O-acetylbuxodienin-E\u2014Zwei neue Alkaloide aus Buxus sempervirens L.","volume":"13","year":"1973","journal-title":"Z. Chem."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"612","DOI":"10.1039\/b704958g","article-title":"Terpenoid alkaloids of the Buxaceae family with potential biological importance","volume":"25","author":"Devkota","year":"2008","journal-title":"Nat. Prod. Rep."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Bienz, S., Bigler, L., Fox, T., and Meier, H. (2016). Spektroskopische Methoden in der Organischen Chemie, Georg Thieme Verlag.","DOI":"10.1055\/b-004-129729"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1515\/znb-2006-0215","article-title":"New Triterpenoidal Alkaloids from Buxus hyrcana","volume":"61","author":"Meshkatalsadat","year":"2006","journal-title":"Z. Naturforsch. B"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"\u010cern\u00fd, V., and \u0160orm, F. (1967). Chapter 8 Steroid Alkaloids: Alkaloids of Apocynaceae and Buxaceae; The Alkaloids: Chemistry and Physiology, Elsevier.","DOI":"10.1016\/S1876-0813(08)60204-3"},{"key":"ref_32","unstructured":"Blaschek, W., and Hager, H. (2007). Hagers Enzyklop\u00e4die der Arzneistoffe und Drogen. Mit 600 Tabellen, Wiss. Verl.-Ges. 6., neu bearb. und erg. Aufl."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"104753","DOI":"10.1016\/j.bioorg.2021.104753","article-title":"Structurally diverse alkaloids from Buxus sempervirens with cardioprotective activity","volume":"109","author":"Xiang","year":"2021","journal-title":"Bioorg. Chem."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"8230","DOI":"10.1016\/j.tetlet.2007.09.074","article-title":"A simple method for the alkaline hydrolysis of esters","volume":"48","author":"Theodorou","year":"2007","journal-title":"Tetrahedron Lett."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Nnadi, C.O., Nwodo, N.J., Kaiser, M., Brun, R., and Schmidt, T.J. (2017). Steroid Alkaloids from Holarrhena africana with Strong Activity against Trypanosoma brucei rhodesiense. Molecules, 22.","DOI":"10.3390\/molecules22071129"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"68","DOI":"10.1002\/cmdc.201900544","article-title":"Structure-Activity Relationships of Cinnamate Ester Analogues as Potent Antiprotozoal Agents","volume":"15","author":"Bernal","year":"2020","journal-title":"Chem. Med. Chem."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"865","DOI":"10.3389\/fphar.2020.00865","article-title":"Mining Sudanese Medicinal Plants for Antiprotozoal Agents","volume":"11","author":"Mahmoud","year":"2020","journal-title":"Front. Pharmacol."}],"container-title":["Antibiotics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-6382\/10\/6\/696\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:12:52Z","timestamp":1760163172000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-6382\/10\/6\/696"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,6,10]]},"references-count":37,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2021,6]]}},"alternative-id":["antibiotics10060696"],"URL":"https:\/\/doi.org\/10.3390\/antibiotics10060696","relation":{},"ISSN":["2079-6382"],"issn-type":[{"value":"2079-6382","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,6,10]]}}}