{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T15:07:29Z","timestamp":1785424049684,"version":"3.56.0"},"reference-count":26,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T00:00:00Z","timestamp":1778198400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Research Fund-Kenya"},{"id":[{"id":"https:\/\/ror.org\/05pwhmm02","id-type":"ROR","asserted-by":"publisher"}]},{"name":"German Academic Exchange Service"},{"name":"Apothekerstiftung Westfalen-Lippe"},{"id":[{"id":"https:\/\/ror.org\/051md9f18","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Plants"],"abstract":"<jats:p>Buxus obtusifolia (Mildbr.) Hutch is an evergreen shrub endemic to East Africa and is traditionally used to treat chest ailments. Our recent investigation on the dichloromethane leaf extract of this species yielded several aminosteroid alkaloids, some of which demonstrated promising in vitro antiprotozoal activity warranting more detailed studies on this interesting plant and its bioactive constituents. Given that abiotic factors are known to influence the biosynthesis and accumulation of plant secondary metabolites, this study aimed to investigate seasonal and organ-specific variability in the alkaloid profile of B. obtusifolia to gain insights into the dynamics of their formation and, potentially, obtain hints at the best times to harvest individual alkaloids. Consequently, leaf and twig samples were collected each month from the same population over a period of one year and analyzed using ultra-high-performance liquid chromatography coupled with positive-mode electrospray ionization double quadrupole time-of-flight tandem mass spectrometry (UHPLC\u2013ESI+\u2013QqTOF\u2013MS\/MS). The resulting data, after conversion to &lt;retention time: mass\/charge ratio&gt; (&lt;tR:m\/z&gt;) variables, were analyzed by principal component analysis (PCA) to characterize variations in the metabolite profile. Evaluation of the first three principal components revealed clear differences between leaves and twigs, as well as subtle overall seasonal changes with some distinct dry-season clustering. A volcano plot was used to further analyze the differences between the minor constituents of the two organs. In total, 15 aminosteroid alkaloids were identified as key contributors to these differences. This represents the first seasonal and organ-specific phytochemical variability investigation in B. obtusifolia. Thus, this study offered the first valuable insights into the possible association of some abiotic factors and the phytochemical profile of this plant. Studies including further populations of this species from different locations will have to show whether the present findings allow general conclusions with respect to the investigated compounds\u2019 accumulation in response to external factors. Furthermore, the present results represent a basis to delineate the optimal harvest period for targeted isolation of larger quantities of bioactive aminosteroids for further development.<\/jats:p>","DOI":"10.3390\/plants15101439","type":"journal-article","created":{"date-parts":[[2026,5,11]],"date-time":"2026-05-11T20:14:16Z","timestamp":1778530456000},"page":"1439","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Seasonal and Organ-Specific Variations of Alkaloids in Buxus obtusifolia (Mildbr.) Hutch: A Multivariate LC\/MS Study"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9638-3250","authenticated-orcid":false,"given":"Justus Wambua","family":"Mukavi","sequence":"first","affiliation":[{"name":"Pharma Campus, Institute of Pharmaceutical Biology and Phytochemistry (IPBP), University of M\u00fcnster, Corrensstra\u00dfe 48, D-48149 M\u00fcnster, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jandirk","family":"Sendker","sequence":"additional","affiliation":[{"name":"Pharma Campus, Institute of Pharmaceutical Biology and Phytochemistry (IPBP), University of M\u00fcnster, Corrensstra\u00dfe 48, D-48149 M\u00fcnster, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5171-1940","authenticated-orcid":false,"given":"Njogu M.","family":"Kimani","sequence":"additional","affiliation":[{"name":"Department of Physical Sciences, University of Embu, P.O. Box 6, Embu 60100, Kenya"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5821-8307","authenticated-orcid":false,"given":"Leonidah Kerubo","family":"Omosa","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science & Technology, University of Nairobi, P.O. Box 30197, Nairobi 00100, Kenya"}],"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":"Pharma Campus, Institute of Pharmaceutical Biology and Phytochemistry (IPBP), University of M\u00fcnster, Corrensstra\u00dfe 48, D-48149 M\u00fcnster, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,8]]},"reference":[{"key":"ref_1","unstructured":"Beentje, H., Adamson, J., and Bhanderi, D. (1994). Kenya Trees, Shrubs, and Lianas, National Museums of Kenya."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Mukavi, J.W., Cal, M., Kaiser, M., M\u00e4ser, P., Kimani, N.M., Omosa, L.K., and Schmidt, T.J. (2025). Antiprotozoal Aminosteroid Alkaloids from Buxus obtusifolia (Mildbr.) Hutch. Molecules, 30.","DOI":"10.3390\/molecules30234558"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"889","DOI":"10.1007\/s11101-018-9567-z","article-title":"The Effects of Season and Water Availability on Chemical Composition, Secondary Metabolites and Biological Activity in Plants","volume":"17","author":"Prinsloo","year":"2018","journal-title":"Phytochem. Rev."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"558","DOI":"10.1016\/j.indcrop.2012.06.020","article-title":"Influencing the Product Quality by Deliberately Applying Drought Stress during the Cultivation of Medicinal Plants","volume":"42","author":"Selmar","year":"2013","journal-title":"Ind. Crops Prod."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Sengnon, N., Vonghirundecha, P., Chaichan, W., Juengwatanatrakul, T., Onthong, J., Kitprasong, P., Sriwiriyajan, S., Chittrakarn, S., Limsuwanchote, S., and Wungsintaweekul, J. (2023). Seasonal and Geographic Variation in Alkaloid Content of Kratom (Mitragyna speciosa (Korth.) Havil.) from Thailand. Plants, 12.","DOI":"10.3390\/plants12040949"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"147","DOI":"10.47583\/ijpsrr.2023.v80i01.022","article-title":"Effect of Seasonal Variations on the Phytochemical Composition and Antioxidant Activity of the Root Extract of Thalictrum foliolosum","volume":"80","author":"Kaushal","year":"2023","journal-title":"Int. J. Pharm. Sci. Rev. Res."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"AlZunaydi, D.A., Alharbi, A.B., and Alfarhan, A.H. (2025). Impact of Season on Chemical Composition of Some Medicinal Plants in Saudi Arabia. Life, 15.","DOI":"10.3390\/life15030336"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.funeco.2017.06.003","article-title":"Plant Age and Seasonal Timing Determine Endophyte Growth and Alkaloid Biosynthesis","volume":"29","author":"Fuchs","year":"2017","journal-title":"Fungal Ecol."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Lin, W., Kuang, Y., Wang, J., Duan, D., Xu, W., Tian, P., Nzabanita, C., Wang, M., Li, M., and Ma, B. (2019). Effects of Seasonal Variation on the Alkaloids of Different Ecotypes of Epichlo\u00eb Endophyte-Festuca Sinensis Associations. Front. Microbiol., 10.","DOI":"10.3389\/fmicb.2019.01695"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Szab\u00f3, L.U., and Schmidt, T.J. (2021). Investigation of the Variability of Alkaloids in Buxus sempervirens L. Using Multivariate Data Analysis of LC\/MS Profiles. Molecules, 27.","DOI":"10.3390\/molecules27010082"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Sch\u00e4fer, L., Sendker, J., and Schmidt, T.J. (2025). Seasonal, Organ-, and Location-Dependent Variations in the Alkaloid Content of Pachysandra terminalis Investigated by Multivariate Data Analysis of LC-MS Profiles. Plants, 14.","DOI":"10.3390\/plants14193060"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"154545","DOI":"10.1016\/j.jplph.2025.154545","article-title":"Optimizing Plant Alkaloid Biosynthesis under Drought Stress: Regulatory Mechanisms and Biotechnological Strategies","volume":"311","author":"Guo","year":"2025","journal-title":"J. Plant Physiol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"100241","DOI":"10.1016\/j.stress.2023.100241","article-title":"Drought Stress-Mediated Alterations in Secondary Metabolites and Biosynthetic Gene Expression in Cumin Plants: Insights from Gene-Specific and Metabolite-Level Analyses","volume":"10","author":"Ghasemi","year":"2023","journal-title":"Plant Stress"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"352","DOI":"10.1111\/pbi.14501","article-title":"Wheat TaPYL9-Involved Signalling Pathway Impacts Plant Drought Response through Regulating Distinct Osmotic Stress-Associated Physiological Indices","volume":"23","author":"Zhang","year":"2025","journal-title":"Plant Biotechnol. J."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"108259","DOI":"10.1016\/j.plaphy.2023.108259","article-title":"The Molecular Paradigm of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) with Different Phytohormone Signaling Pathways during Drought Stress in Plants","volume":"206","author":"Samanta","year":"2024","journal-title":"Plant Physiol. Biochem."},{"key":"ref_16","first-page":"100100","article-title":"Environmental Stress Induced Biosynthesis of Plant Secondary Metabolites- Transcriptional Regulation as a Key","volume":"4","author":"Gaude","year":"2025","journal-title":"Crop Des."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1038\/s43586-022-00184-w","article-title":"Principal Component Analysis","volume":"2","author":"Greenacre","year":"2022","journal-title":"Nat. Rev. Methods Prim."},{"key":"ref_18","first-page":"20150202","article-title":"Principal Component Analysis: A Review and Recent Developments","volume":"374","author":"Jollife","year":"2016","journal-title":"Philos. Trans. A Math. Phys. Eng. Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"138","DOI":"10.1016\/j.steroids.2011.11.001","article-title":"Rapid Characterization and Identification of Steroidal Alkaloids in Sarcococca coriacea Using Liquid Chromatography Coupled with Electrospray Ionization Quadropole Time-of-Flight Mass Spectrometry","volume":"77","author":"Musharraf","year":"2012","journal-title":"Steroids"},{"key":"ref_20","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_21","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1002\/rcm.6441","article-title":"Structure-Fragmentation Relationship and Rapid Dereplication of Buxus Steroidal Alkaloids by Electrospray Ionization-Quadrupole Time-of-Flight Mass Spectrometry","volume":"27","author":"Musharraf","year":"2013","journal-title":"Rapid Commun. Mass Spectrom."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"4563","DOI":"10.1016\/S0040-4020(01)92557-8","article-title":"Buxus Alkaloids\u2014XII: Benzamide Alkaloids from Buxus sempervirens L.","volume":"23","author":"Kupchan","year":"1967","journal-title":"Tetrahedron"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1780","DOI":"10.1016\/j.phytochem.2010.06.017","article-title":"Triterpenoidal Alkaloids from Buxus hyrcana and Their Enzyme Inhibitory, Anti-Fungal and Anti-Leishmanial Activities","volume":"71","author":"Ata","year":"2010","journal-title":"Phytochemistry"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Szab\u00f3, L., Kaiser, M., M\u00e4ser, P., and Schmidt, T.J. (2021). Antiprotozoal Nor-Triterpene Alkaloids from Buxus sempervirens L.. Antibiotics, 10.","DOI":"10.3390\/antibiotics10060696"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"155815","DOI":"10.1016\/j.tetlet.2025.155815","article-title":"Triterpenoid Alkaloids from Buxus bodinieri and Their Bioactivities","volume":"171\u2013172","author":"Zha","year":"2025","journal-title":"Tetrahedron Lett."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"3111","DOI":"10.1021\/acs.jnatprod.9b00652","article-title":"Buxaustroines A-N, a Series of 17(13\u219218) abeo-Cycloartenol Triterpenoidal Alkaloids from Buxus austro-yunnanensis and Their Cardioprotective Activities","volume":"82","author":"Xiang","year":"2019","journal-title":"J. Nat. Prod."}],"container-title":["Plants"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2223-7747\/15\/10\/1439\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T04:46:46Z","timestamp":1778561206000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2223-7747\/15\/10\/1439"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,8]]},"references-count":26,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2026,5]]}},"alternative-id":["plants15101439"],"URL":"https:\/\/doi.org\/10.3390\/plants15101439","relation":{},"ISSN":["2223-7747"],"issn-type":[{"value":"2223-7747","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,8]]}}}