Two pseudoguianolide sesquiterpenes were isolated as antiallergic constituents of Centipeda minima, which has been used as a folk medicine in southeast Asia. One of the sesquiterpenes, 6-O-senesioylplenolin (2), is a new pseudoguaianolide sesquiterpene lactone, which was isolated along with known pseudoguaianolide, arnicolide C (1). The two sesquiterpenes exhibited significant antiallergy activity in passive cutaneous anaphylaxis (PCA) tests. An amide isolated along with the sesquiterpenes was identified as aurantiamide acetate (3). Three flavonoids obtained from this plant also showed significant antiallergy activity.
