Bauer ketones 23 and 24 from Echinacea paradoxa var. paradoxa inhibit lipopolysaccharide-induced nitric oxide, prostaglandin E2 and cytokines in RAW264.7 mouse macrophages

► Echinacea species were screened for anti-inflammatory activity in RAW264.7 cells. ► Echinacea paradoxa var. paradoxa showed the most potent anti-inflammatory activity. ► Bioactivity-guided fractionation led to identification of Bauer ketones 23 and 24. ► They inhibited LPS-induced NO and PGE2 without reducing iNOS and COX2 protein level. ► Bauer ketone 24 contributed to inhibition of LPS-induced IL-1β and IL-6 secretion.