– Three new quinoline alkaloids, 4-acetyl-6-methyl-7-(3-methyl-2-oxobut-3-enyl)quinolin-2(1H)-one (1), 4-acetyl-5-methyl-7-(3-methyl-2-oxobut-3-enyl)quinolin-2(1H)-one (2), and 4-acetyl-6-methyl-7-prenylquinolin-2(1H)-one (3) were isolated from the whole plants of Thalictrum glandulosissimum. Their structures were elucidated by spectroscopic methods, including extensive 1H, 13C, and 2D-NMR techniques. Compounds 1-3 were also tested for their anti-rotavirus activity. Compounds 1-3 exhibited potent anti-rotavirus activity with therapeutic index (TI) valves of 17.6, 15.0, and 23.6 respectively. © 2021 The Japan Institute of Heterocyclic Chemistry