In vitro anti-inflammatory activity of the hydroethanolic extract of Morus nigra leaves
Morus nigra; medicinal plants; inflammation; PPAR
Inhibition of systemic inflammation has been a beneficial strategy in treating several noncommunicable diseases, which represent one of the major causes of mortality in the world. The Peroxisome Proliferator-Activated Receptors (PPAR) are interesting pharmacological targets, since they can act both through the metabolic and anti-inflammatory pathways. Morus nigra L. has flavonoids in its chemical composition with recognized antioxidant activity and often associated with anti-inflammatory activity. Therefore, this study aimed to evaluate the hydroethanolic extract of M. nigra leaves' ability to activate PPARs and promote anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated murine macrophage cells. The leaf extract was prepared by cold maceration, and the chemical profile was obtained by HPLC-DAD. The cytotoxicity of the extract was tested by the MTT method on RAW 264.7 and HeLa cells. Activation of the PPAR and γ, and the Tr was tested using the luciferase genereporter assay in HeLa cells. The anti-inflammatory capacity of the extract was evaluated after the treatment of LPS-stimulated RAW 264.7 cells. HPLC analysis revealed the presence of rutin (3.74 µg/mg) and isoquercitrin (5.92 µg/mg). Low extract cytotoxicity was observed for the tested strains. The extract showed agonist activity for both types of PPAR ( and γ), but its major compounds (rutin and isoquercitrin) did not significantly activate the receptor. The extract was able to reduce the production of nitric oxide, reactive oxygen species and the pro-inflammatory cytokine TNF-α. Treatment with the specific PPAR-α antagonist, GW 6471, was able to partially block the anti-inflammatory effect caused by the extract. Thus, possibly the anti-inflammatory effect of the extract can be attributed, at least in part, to the activation of the PPAR-α receptor, being the first study to evaluate the activation of this receptor by the extract of the leaves of M. nigra L.”