Karafsin, a unique mono-acylated flavonoid apiofurnoside from the leaves of Apium graveolens var. secalinum Alef: In vitro and in vivo anti-inflammatory assessment

Abstract Celery ethanol extract (CEE) of leaves of Apium graveolens var. secalinum Alef, showed high phenolic content with significant antioxidant activity using DPPH and ORAC assay. Two unique unknown compounds, apigenin 7-O-mono-apiofuranoside and acylated flavonoid, 7-O- (5″-E-p-coumaroyl)-apiofuranside (karafsin) were identified in CEE for the first time by a full structural analysis, along with 6 known compounds. While karafsin significantly inhibited cyclooxygenase-2 by 42.52 ± 2.88 and 70.33 ± 2.97 % at 50 and 100 mg/mL and 5-lipoxygenase by 37.33 ± 2.87 and 75.77 ± 2.57 % at 50 and 100 mg/mL in raw macrophage cells challenged with Escherichia coli lipopolysaccharide, CEE exhibited the same weigh-dose activity as a crude extract mixture. Comparable inhibition of NO was also observed by CEE versus karafsin at approximately 0.06 mg/mL. Thus, CEE as a mixture has potent anti-inflammatory activity, of which the formulated 1% topical gel was found to have a 79.51 % inhibition of edema in the carrageenan-induced rat paw model, comparable as the commercial 1% diclofenac gel. CEE has potent anti-inflammatory activity and this warrants additional investigations.