Antimicrobially active hederagenin glycosides from Cephalaria elmaliensis

A phytochemical investigation of the aerial parts of Cephalaria elmaliensis resulted in the isolation of ten hederagenin-type triterpene saponins (1-10) including three new ones, elmalienoside A (1), elmalienoside B (2), elmalienoside C (3), and two known flavonoid glycosides (11-12). Their structures were identified by extensive spectroscopic techniques (1D and 2D NMR, HR ESIMS) and chemical evidence. The antimicrobial activity of the extracts and the pure compounds was evaluated by the MIC method. According to the results, all pure compounds including the new ones were found to be very active against both gram-positive and gram-negative bacteria.