Phenolic Profiles and Cytotoxic Activities of Methanolic Extracts From Eight Geranium L. Species

This study comparatively characterized the phenolic profiles and in vitro cytotoxic activity of methanolic extracts from aerial and underground parts of eight Geranium species native to Serbia (Geranium macrorrhizum, Geranium robertianum, Geranium phaeum, Geranium sanguineum, Geranium palustre, Geranium pyrenaicum, Geranium columbinum, and Geranium lucidum). Phenolic constituents were analysed by LC-PDA/MS, and cytotoxicity against human cancer cell lines (HeLa, PC-3, HT-29, Hs-294T) and normal lung fibroblasts (MRC-5) was evaluated using the MTT assay. Ellagitannins predominated, followed by phenolic acids and flavonols, with pronounced species- and organ-specific variability. Some phenolics were identified for the first time in specific taxa and organs. Several extracts showed selective cytotoxicity, mainly against HeLa cells, with the strongest activity observed for underground parts of G. sanguineum (IC₅₀ = 2.52 µg/mL). Geraniin demonstrated selective cytotoxic effects. These findings highlight the chemical diversity and biological potential of the investigated Geranium species and support further mechanistic and in vivo studies.