Study on Anti-Inflammatory Activity of Niloticin by Targeting MD-2 Based on Computer-Aided Drug Design and Biolayer Interferometry

Abstract

Niloticin is an active compound from Cortex phellodendri, but its antiinflammatory activity has not yet been explored. The aim of the present study was to assess the drug potential of niloticin and to study the MD-2-targeting mechanism of its anti-inflammatory activity. Niloticin’s drug potential was analyzed using the Traditional Chinese Medicine Systems Pharmacology Database. Molecular docking and biolayer interferometry technology were used to explore the anti-inflammatory mechanism of niloticin by targeting myeloid differentiation protein 2 (MD-2), which mediates a series of Toll-Like Receptor (TLR) 4-dependent inflammatory responses. The cytokines involved in the LPSTLR4/ MD-2-NF-κB pathway were evaluated by ELISA, RT-PCR, and western blot. The results showed that niloticin has drug potential and could bind to MD- 2. Niloticin had no impact on cell viability. Niloticin could significantly decrease the levels of NO, IL-6, TNF-a, and IL-1β (P<0.01) induced by LPS. IL-1β, IL-6, iNOS, TNF-a, and COX-2 mRNA expression levels were decreased by niloticin (all P<0.01). Compared with the control group, TLR4, p65, MyD88, p-p65, and iNOS expression levels induced by LPS were suppressed by niloticin (all P<0.01). In conclusion, niloticin is a potential MD-2 antagonist. It might interact with MD-2 to play an anti-inflammatory role by suppressing the activation of the LPS-TLR4/MD-2-NF-κB signaling pathway.