japonica, we recently isolated sesquiterpene lactones including 1-oxo-4aH-eudesma-5 (6), 11 ( 13 ) -dien-12,8尾- olide ( OE ), and 6伪-isovaleryloxy-l-hydroxy-4伪H-1,10-secoeudesma-5 ( 10 ), 11 ( 13 )-dien-12,8尾-olide ( IHS ) from the extract of I. japonica, and ...