A Japanese cultivar of Gaillardia pulchella Foug. (Tenningiku) contained, in addition to the pseudoguaianolides, pulchellin(1) and neopulchellin(2), the guaianolide, gaillardin(4) apparently accompanied by its new epimer neogaillardin(5) and a new bromine-containing base Compound I(9),C_6H_<11>O_2N_2Br, entirely different from novel sesquiterpene alkaloids, pulchellidine(6) and neopulchellidine(7) found in a Florida collection. The structure of a minor new constituent, pulchellon(8), C_<12>H_<18>O_3, isolated also from the Florida collection, has been proposed, and that of another unique principle(9) mentioned above has been completely elucidated by chemical reactions and X-ray analysis. A possible biogenetic scheme for all the sesquiterpene lactones so far isolated from Gaillardia pulchella, including the eudesmanolides, pulchellin B, C, E and F(3a,b,c,d) found in a Texas race, is proposed in Fig. 2. Fig. 1 shows that especially for pulchellon(8) originating from pulchellin(1) and/or neopulchellin(2).
