Antifeedants for the larvae of the yellow butterfly, Eurema hecabe mandarina, in Lycoris radiata.

In addition to the eight known compounds two new constituents were isolated as antifeedants for the larvae of the yellow butterfly, Eurema hecabe mandarina de 1' Orza, from the methanol extract of Lycoris radiata Herb. Their structures were established to be (-)-3'-hydroxy-4'-methoxy-7-hydroxy-8-methylflavan (I) and O-methyl-lycorenine (III) on the basis of spectral evidence. Final evidence for the structure of I came from the synthesis of the racemate. Two of the known compounds, galanthamine and lycoramine, were isolated as carbonate. In addition to I and demethylhomolycorine (IV), lycoricidinol (VII) and lycoricidine (VIII), reported as plant growth inhibitors, were main antifeedants in L. radiata.