Two new lupine alkaloids, (-)-13α-tigloyloxymultiflorine [2] and (+)-(trans-4'-acetoxycinnamoyl)epilupinine [10], were isolated from 7- to 10-day-old seedlings of Lupinus hirsutus (blue lupine) together with ten known alkaloids. The structures of the new alkaloids were confirmed by spectroscopic methods and by chemical transformations. We also clarified variations of the alkaloidal content at various stages of seedling growth. Plants of the genus Lupinus (Leguminosae) are known to contain a variety of structural types of lupine alkaloids (1). They have been used as ornamental plants and as economic plants for fodder and for soil nitrogenation. We have already reported that certain members of the genus Lupinus are rich in esters of bicyclic quinolitidine alkaloids with the derivatives of cinnamic acid (2-8). We recently have reported the isolation and structural determination of two new glycosidic lupine alkaloids from the aerial parts of Lupinus hirsutus and the distribution of alkaloids in several organs of the mature plant (2). In the present paper, we describe the isolation of two new lupine alkaloids, (-)-13α-tigloyloxymultiflorine [2] and (+)-(trans-4'-acetoxycinnamoyl)epilupinine [10], from the seedlings of L. hirsutus together with ten known alkaloids: (-)-multiflorine [1], (-)-Δ⁵-dehydromultiflorine [3], (+)-epilupinine [4], (+)-epilupinine N-oxide [5], (+)-epilupinine acetate N-oxide [6], (+)-(trans-4'-hydroxy-3'-methoxycinnamoyl)epilupinine [7], (+)-(trans-4'-hydroxycinnamoyl)epilupinine [8], (+)-(cis-4'-hydroxycinnamoyl)epilupinine [9], (-)-(trans-4'-α-L-rhamnosyloxycinnamoyl)epilupinine [11], and (-)-(cis-4'-α-L-rhamnosyloxycinnamoyl)epilupinine [12]. We have also revealed variations of the alkaloidal contents in the growth time-course of L. hirsutus seedlings.