{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,10]],"date-time":"2026-09-10T10:11:01Z","timestamp":1789035061712,"version":"build-2803163510"},"reference-count":24,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,9,10]],"date-time":"2026-09-10T00:00:00Z","timestamp":1788998400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan","award":["AP23489874"],"award-info":[{"award-number":["AP23489874"]}]},{"award":["AP23489874"],"award-info":[{"award-number":["AP23489874"]}],"id":[{"id":"https:\/\/ror.org\/05tyne317","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antioxidants"],"abstract":"<jats:p>A systematic phytochemical investigation of the leaves of Crataegus almaatensis Pojark., an endemic hawthorn species native to the mountainous regions of Kazakhstan, was carried out. Multi-step chromatographic fractionation, comprising ultrasound-assisted methanol extraction, sequential liquid\u2013liquid partitioning, silica gel column chromatography, and preparative HPLC, afforded five phenolic compounds as individual, spectroscopically homogeneous constituents from the ethyl acetate fraction. The structures of all isolated compounds were elucidated by comprehensive analysis of high-resolution mass spectrometry (HR-ESI-QTOF-MS) data and one- and two-dimensional NMR spectroscopy (1H, 13C, HSQC, HMBC) in DMSO-d6. The following compounds were identified: (\u2212)-epicatechin, cinchonain Ia, a methoxy- and hydroxy-substituted diaryl ether \u03b2-D-glucopyranoside, kakispyrol, and a dimethoxy-substituted diaryl ether \u03b2-D-glucopyranoside. The isolated compounds belong to three chemical classes: flavanols, flavolignans, and diaryl ether-type phenolic glycosides. Evaluation of ABTS and DPPH radical-scavenging activity revealed compound-specific antioxidant profiles, with compound 5 (cinchonain Ia) showing activity comparable to the ascorbic acid standard. This study provides, for the first time, a detailed structural characterization of individual phenolic metabolites from C. almaatensis leaves and makes a significant contribution to understanding the chemical diversity of this endemic species.<\/jats:p>","DOI":"10.3390\/antiox15091149","type":"journal-article","created":{"date-parts":[[2026,9,10]],"date-time":"2026-09-10T09:13:03Z","timestamp":1789031583000},"page":"1149","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Phytochemical Investigation of Crataegus almaatensis Leaves: Isolation, Structural Characterization, and Antioxidant Activity of Flavonoids, Flavolignans, and Phenolic Glycosides"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7258-746X","authenticated-orcid":false,"given":"Zhanar","family":"Nabiyeva","sequence":"first","affiliation":[{"name":"Research Institute of Food Safety, Almaty Technological University, Almaty 050012, Kazakhstan"},{"name":"Department of Applied Biotechnology, Almaty Technological University, Almaty 050012, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3878-8185","authenticated-orcid":false,"given":"Akerke","family":"Kulaipbekova","sequence":"additional","affiliation":[{"name":"Department of Applied Biotechnology, Almaty Technological University, Almaty 050012, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Asylbek","family":"Kozybayev","sequence":"additional","affiliation":[{"name":"Faculty of Biotechnology and Chemical Technologies, Almaty Technological University, Almaty 050012, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Handi","family":"Yang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Geriatric Nutrition and Health, Ministry of Education of China, School of Light Industry Science and Engineering, Beijing Technology and Business University, Beijing 100048, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9162-3355","authenticated-orcid":false,"given":"Fuhang","family":"Song","sequence":"additional","affiliation":[{"name":"Key Laboratory of Geriatric Nutrition and Health, Ministry of Education of China, School of Light Industry Science and Engineering, Beijing Technology and Business University, Beijing 100048, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5286-5175","authenticated-orcid":false,"given":"Abdyssemat","family":"Samadun","sequence":"additional","affiliation":[{"name":"Research Institute of Food Safety, Almaty Technological University, Almaty 050012, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elmira","family":"Assembayeva","sequence":"additional","affiliation":[{"name":"Department of Applied Biotechnology, Almaty Technological University, Almaty 050012, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3550-1668","authenticated-orcid":false,"given":"Nasi","family":"Ai","sequence":"additional","affiliation":[{"name":"Key Laboratory of Geriatric Nutrition and Health, Ministry of Education, Beijing Technology and Business University, Beijing 100048, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1021\/acs.jafc.5c11498","article-title":"Research progress on the chemical composition and pharmacological effects of hawthorn (Crataegus spp.): A review","volume":"74","author":"Wang","year":"2026","journal-title":"J. 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