{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T10:02:35Z","timestamp":1790762555562,"version":"4.1.0"},"reference-count":41,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T00:00:00Z","timestamp":1790726400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Int. J. Mol. Sci.","IJMS"],"abstract":"<jats:p>Giardiasis is a parasitic disease for which there is a growing need to develop new therapeutic alternatives due to the adverse effects associated with first-line treatments such as metronidazole and the increasing emergence of resistant strains. In this study, the in vitro antigiardial activity of three quassinoids, chaparrin (1), amarolide (2), and chaparrinone (3), isolated from the stems of Castela tortuosa Liebm., was evaluated. The compounds were obtained from the methanolic extract through fractionation and chromatographic purification, and their antigiardial activity was determined against Giardia lamblia trophozoites. In addition, in silico studies were conducted to evaluate their physicochemical, pharmacokinetic, and toxicological properties, as well as molecular docking studies against actin, aldose reductase (ARL), and pyruvate: ferredoxin oxidoreductase (PFOR). Chaparrinone (3) exhibited the highest antigiardial activity, with an IC50 18.98 \u03bcg mL\u22121, whereas chaparrin (1) and amarolide (3) showed lower activity. Amarolide (2) exhibited the highest binding affinities toward the molecular targets, while chaparrin (1) showed the most favorable overall toxicological\/ADME profile. Taken together, these findings highlight chaparrinone (3) as a quassinoid of interest for the development of new antigiardial agents and support the need for further enzymatic, pharmacokinetic, and in vivo studies to more precisely determine its therapeutic potential.<\/jats:p>","DOI":"10.3390\/ijms27198733","type":"journal-article","created":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T09:25:42Z","timestamp":1790760342000},"page":"8733","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["In Vitro Antigiardial Activity and In Silico Target Exploration of Quassinoids Isolated from Castela tortuosa Liebm."],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1041-4090","authenticated-orcid":false,"given":"Ulises","family":"Murrieta-Dionicio","sequence":"first","affiliation":[{"name":"Laboratorio de Productos Naturales, \u00c1rea de Qu\u00edmica, Departamento de Preparatoria Agr\u00edcola, Universidad Aut\u00f3noma Chapingo, Chapingo 56230, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1851-5988","authenticated-orcid":false,"given":"Fernando","family":"Calzada","sequence":"additional","affiliation":[{"name":"Unidad de Investigaci\u00f3n M\u00e9dica en Farmacolog\u00eda, UMAE Hospital de Especialidades, 2\u00b0 Piso CORSE Centro M\u00e9dico Nacional Siglo XXI, IMSS, Ciudad de Mexico 06720, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7111-7922","authenticated-orcid":false,"given":"Elizabeth","family":"Barbosa","sequence":"additional","affiliation":[{"name":"Escuela Superior de Medicina, Instituto Polit\u00e9cnico Nacional, Ciudad de Mexico 07738, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7401-303X","authenticated-orcid":false,"given":"Miguel","family":"Valdes","sequence":"additional","affiliation":[{"name":"Unidad de Investigaci\u00f3n M\u00e9dica en Farmacolog\u00eda, UMAE Hospital de Especialidades, 2\u00b0 Piso CORSE Centro M\u00e9dico Nacional Siglo XXI, IMSS, Ciudad de Mexico 06720, Mexico"},{"name":"Escuela Superior de Medicina, Instituto Polit\u00e9cnico Nacional, Ciudad de Mexico 07738, Mexico"},{"name":"Laboratorio de Inmunolog\u00eda, Departamento de Sistemas Biol\u00f3gicos, Universidad Aut\u00f3noma Metropolitana Unidad Xochimilco, Calz. del Hueso 1100, Coapa, Villa Quietud, Coyoac\u00e1n, Ciudad de Mexico 04960, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2673-4366","authenticated-orcid":false,"given":"Jesica","family":"Ramirez-Santos","sequence":"additional","affiliation":[{"name":"Unidad de Investigaci\u00f3n M\u00e9dica en Farmacolog\u00eda, UMAE Hospital de Especialidades, 2\u00b0 Piso CORSE Centro M\u00e9dico Nacional Siglo XXI, IMSS, Ciudad de Mexico 06720, Mexico"},{"name":"Escuela Superior de Medicina, Instituto Polit\u00e9cnico Nacional, Ciudad de Mexico 07738, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9330-2646","authenticated-orcid":false,"given":"Benito","family":"Reyes-Trejo","sequence":"additional","affiliation":[{"name":"Laboratorio de Productos Naturales, \u00c1rea de Qu\u00edmica, Departamento de Preparatoria Agr\u00edcola, Universidad Aut\u00f3noma Chapingo, Chapingo 56230, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6372-2885","authenticated-orcid":false,"given":"Holber","family":"Zuleta-Prada","sequence":"additional","affiliation":[{"name":"Laboratorio de Productos Naturales, \u00c1rea de Qu\u00edmica, Departamento de Preparatoria Agr\u00edcola, Universidad Aut\u00f3noma Chapingo, Chapingo 56230, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lino","family":"Reyes","sequence":"additional","affiliation":[{"name":"Departamento de Qu\u00edmica Org\u00e1nica, Facultad de Qu\u00edmica, Universidad Nacional Aut\u00f3noma de M\u00e9xico, Ciudad Universitaria, Delegaci\u00f3n Coyoac\u00e1n 04510, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1007\/s11686-026-01311-3","article-title":"Anti-Giardia Activity of Pistacia atlantica Hydroalcoholic Extract Against Giardia lamblia Cysts","volume":"71","author":"Tam","year":"2026","journal-title":"Acta Parasitol."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Flores-L\u00f3pez, L.A., L\u00f3pez-Herrera, G., Mart\u00ednez-P\u00e9rez, Y., Matadamas-Ortiz, E.J., G\u00f3mez-Manzo, S., Hern\u00e1ndez-Alc\u00e1ntara, G., Gonz\u00e1lez-Maciel, A., Reynoso-Robles, R., Hern\u00e1ndez-Ochoa, B., and Chino-R\u00edos, L. 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