Masaiti Yanagita

Sesquiterpene lactones of Gaillardia pulchella

Abstract A Japanese cultivar of Gaillardia pulchella Foug. contained, in addition to the pseudoguaianolides, pulchellin(I) and neopulchellin(II), the guaianolide, gaillardin(III) apparently accompanied by its epimer neogaillardin(IV) and an unidentified basic principle different from pulchellidine(V) and neopulchellidine(VI). A possible biogenetic scheme for the sesquiterpene lactones including eudesmanolides, pulchellin-B, -C, -E and -F(VII) is proposed.

Ambrosic Acid, a New Irritant Principle from the Pollen of the Ragweed Ambrosia arthemisiifolia

In connection with our studies on the physiologically active substance in the genus of Gaillardia, Arthemisia and their relatives in Compositae, we have recently investigated a poisonous principle in the common ragweed, Ambrosia arthemisiifolia (Butakusa.) Since this plant was introduced into Japan from North America almost one century ago, it has made a wide distribution over the Japanese islands and been notorious for a cause of pollen allergy (hay fever) and also as a poisonous weed in cattle feed.