The investigation of antibacterial, antifungal, and cytotoxic activities of ethanol extracts from vegetative and generative parts of three Taxus species (T. baccata L., T. cuspidata Siebold et Zucc., and T. canadensis Marsh.) native to Russia was this study’s aim. Cytotoxicity assessment was via the MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) against A-172 (glioblastoma), HeLa (cervical adenocarcinoma), HepG2 (hepatocellular carcinoma), and normal human embryonic mesenchymal stem (FetMSC) cells after 72 h of the treatment. Antifungal activity received comparative determination against Fusarium oxysporum L. and Helminthosporium L. using disc diffusion. Vegetative extracts showed potent cytotoxicity, especially T. canadensis shoots against HeLa and A-172 (IC₅₀ 5.7 ± 0.4 and 6.21 ± 0.3 μg/mL, respectively). However, the aril extracts displayed the lowest toxicity. Antifungal and bacteriostatic results also varied by species and pathogens. These results confirmed Taxus vegetative parts can be effective as promising sources of cytotoxic, antifungal, and antibacterial metabolites. Data on biological activity correlate with the accumulation of polyphenols in the tissues of studied plants. Histochemical studies have shown an abundant content of polyphenols in conductive, reserve, and epidermal tissues.

Keywords: Taxus species, cytotoxicity, antibacterial and antifungal activity, arillus, secondary metabolites

Key findings: Taxus canadensis shoot extracts exhibited the highest cytotoxicity against human cancer cell lines, whereas aril extracts were non-toxic. The yew extracts also revealed species- and organ-specific antibacterial and antifungal activity against the phytopathogenic fungi. Moreover, the research determined the content and localization of various classes of polyphenols of the studied plants.