Naringin lauroyl ester inhibits lipopolysaccharide-induced activation of nuclear factor κB signaling in macrophages

Abstract

Naringin (Nar) has antioxidant and anti-inflammatory properties. It was recently reported that enzymatic modification of Nar enhanced its functions. Here, we acylated Nar with fatty acids of different sizes (C2–C18) using immobilized lipase from Rhizomucor miehei and investigated the anti-inflammatory effects of these molecules. Treatment of murine macrophage RAW264.7 cells with Nar alkyl esters inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) production, with Nar lauroyl ester (Nar-C12) showing the strongest effect. Furthermore, Nar-C12 suppressed the LPS-induced expression of inducible NO synthase by blocking the phosphorylation of inhibitor of nuclear factor (NF)-κB-α as well as the nuclear translocation of NF-κB subunit p65 in macrophage cells. Analysis of Nar-C12 uptake in macrophage cells revealed that Nar-C12 ester bond was partially degraded in the cell membrane and free Nar was translocated to the cytosol. These results indicate that Nar released from Nar-C12 exerts anti-inflammatory effects by suppressing NF-κB signaling pathway.

Graphical abstract

Naringin lauroyl ester inhibits LPS-induced activation of NF-κB signaling in macrophages.

Key words:

• Naringin
• acylation
• anti-inflammatory activity
• nuclear factor κB

Acknowledgments

We would like to thank Editage (www.editage.jp) for English language editing.

Disclosure statement

The authors have no conflict of interest.

Notes

Abbreviations: DMEM, Dulbecco’s modified Eagle’s medium; FBS, fetal bovine serum; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; HPLC, high-performance liquid chromatography; HRP, horseradish peroxidase; IL-1β, interleukin-1β; iNOS, inducible NO synthase; IκB, inhibitor of NF-κB; LPS, lipopolysaccharide; MAPK, mitogen-activated protein kinase; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide; Nar, naringin; NF-κB, nuclear factor (NF)-κB; Nge, naringenin; NO, nitric oxide; PBS, phosphate-buffered saline; RT-PCR, reverse-transcriptional PCR; SDS, sodium dodecyl sulfate; TPI, triose-phosphate isomerase.