Osmanthus fragrans var. aurantiacus has been used for the treatment of menopausal pain, foul breath, and intestinal bleeding. Four phenylpropyl triterpenoids, 3-O-trans-p-coumaroyltormentic acid (1), 3β-trans-p-coumaroyloxy-2α-hydroxyl-urs-12-en-28-oic acid (2), 3β-cis-p-coumaroyloxy-2α-hydroxyl-urs-12-en-28-oic acid (3), 3-O-cis-coumaroylmaslinic acid (4), were isolated from the leaves of O. fragrans var. aurantiacus and the inhibitory effect on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced macrophages were evaluated. Among them, compounds 2-4 concentration dependently showed NO production inhibitory effects. To determine the signaling factors involved in the inhibition of NO production by compounds 2-4, we assessed anti-inflammatory activity. Western blot analysis revealed compounds 2-4 significantly decreased the expression of LPS-stimulated protein, inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, nuclear factor-kappa B (NF-κB) and phosphorylated extracellular regulated kinase (pERK)1/2. Also, compounds 2-4 downregulated tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and IL-8 levels in LPS-induced macrophages and colonic epithelial cells. This study demonstrated that phenylpropyl triterpenoids 2-4 isolated from O. fragrans var. aurantiacus leaves can be used as potential candidates for the prevention and treatment of inflammatory bowel disease.
Keywords: HT-29; Inflammatory bowel disease; Osmanthus fragrans var. aurantiacus; Phenylpropyl triterpenoids; RAW 264.7.
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