A Bio-Guided Fractionation to Assess the Inhibitory Activity of Calendula officinalis L. on the NF-κB Driven Transcription in Human Gastric Epithelial Cells

Calendula officinalis L. has been largely known for its topical anti-inflammatory properties; however, there are no experimental evidences about its antiphlogistic effect at the gastric level. To investigate whether marigold might exert an activity against gastric inflammation, a CH2Cl2 extract obtained from C. officinalis flowers was evaluated in vitro on the NF-κB pathway. The lipophilic extract demonstrated a significant inhibitory effect on the NF-κB driven transcription. The identification of active compounds was conducted by a bio-guided fractionation of the extract that afforded 16 fractions. Fraction J exhibited a concentration-dependent inhibitory activity on the NF-κB driven transcription and significantly contributed to the antiphlogistic effect showed by CH2Cl2 extract. The main components of fraction J were loliolide and the fucoside acetates of β-eudesmol and viridiflorol. HPLC analysis of fractions D and E led to the identification and isolation of triterpene esters that showed a concentration-dependent inhibition of the NF-κB driven transcription, with faradiol-3-myristate and the corresponding aglycone being the most active compounds. The present study provides some experimental evidences that Calendula officinalis L. may exert an anti-inflammatory activity on the gastric district by the inhibition of the NF-κB system, identifying the compounds responsible, at least in part, for the observed effect.