SESQUITERPENE LACTONES AND LIGNANES FROM RUDBECKIA SPECIES

Rudbeckia grandiflora, R. subtomentosa, R. nitida var. texana, R. scabrifolia and R. maxima were investigated for their secondary constituents. Rudbeckia subtomentosa leaves afforded the known sesquiterpene lactones 4-O-desacetylligulatine C, and ligulatine C; the flowers provided costunolide, santamarine, reynosin, the flavonol eupatolin plus a mixture of β-sitosterol and stigmasterol; the roots gave costunolide, 11,13-dihydrocostunolide, gazaniolide, isogazaniolide, tamaulipin A angelate, caryophyllene, caryophyllene oxide and β-selinene. Rudbeckia nitida var. texana, R. scabrifolia and R. maxima gave the lignanes (+)-pinoresinol dimethyl ether and yangambin. The germacrolide tamaulipin A angelate, was the major constituent of root extracts of R. grandiflora. Structure and stereochemistry of the new lactones were elucidated by spectroscopic methods. The molecular structures of gazaniolide. © 1990.