Alkaloids from Lindera aggregata.

Eight alkaloids, including a new compound, (+)-norboldine acetate (1), and seven known ones, (+)-norboldine (2), (+)-boldine (3), (+)-laurotetanine (4), (+)-N-methyllaurotetanine (5), (+)-reticuline (6), (-)-pronuciferine (7), and pallidine (8) were isolated from the roots of Lindera aggregata. The structures of these alkaloids were determined by spectroscopic and chemical methods, especially 2D NMR techniques, which also allowed the first full NMR assignments of alkaloids 2, 4 and 5. Among them, the 1D NMR chemical shifts of (+)-norboldine (2) showed a remarkable environmental sensitive behavior. All the alkaloids were tested in cytotoxicity assays against L1210 and K562 tumor cell lines; only (+)-norboldine (2) showed weak activity against the L1210 cell line.