In vitro anti-inflammatory activity of Malus × domestica var. Mela Rosa Marchigiana pulp callus extract contrasting high glucose conditions

The anti-inflammatory activity of the “Mela Rosa Marchigiana” (MRM) pulp callus ethanol Extract (MRME) was tested in different cellular models including (i) LPS-treated RAW 264.7; (ii) HUVEC exposed to short-term high Glucose (HG, 45 mM) or normal glucose (NG, 5 mM) concentrations; and (iii) HG (30 mN) and LPS-treated U937. To evaluate the anti-inflammatory effect of the extract, Nitric Oxide (NO) production was measured in RAW 264.6 cells, while IL-8, IL-1ß and MCP-1 expressions, along with modulation of some inflammation- or senescence-associated miRNAs (miR-21, miR-126, miR-17 and miR-217) were assessed in HUVECs and/or U937. MRME treatment reduced pro-inflammatory markers amount, suggesting a decreased generalised inflammatory response. Present findings indicate that MRME can contrast senescence- or HG-induced inflammation. Moreover, in HG- and LPS-induced inflammation, MRME reduced U937 monocyte activation by inhibiting mitochondrial respiration and inflammatory markers. Finally, the inhibitory potential of MRME on the digestive enzymes α-glucosidase, α-amylase and lipase activity was investigated. Our results support the idea that MRME has a positive effect on inhibition of endothelial/macrophage dysfunction under HG/senescence inflammatory conditions. Furthermore, the obtained results showed a modest inhibitory power of the extract (IC50 values: 2.98 ± 0.24, 1.77 ± 0.15, and 2.06 ± 0.31 mg/ml, respectively), which, however, could be of some help in decreasing the absorption of glucose and triglycerides.