Bio-assay guided isolation of air dried roots of Inula racemosa yielded two known sesquiterpene lactones, dehydrocostus lactone (1) and costunolide (2). The structure of the compounds were established based on physicochemical data and co-comparison with an authentic compounds. The crude extract, fractions and isolated compounds were examined for antimicrobial properties and pure compounds were evaluated for melanin synthesis inhibition property.
