Anti-inflammatory effects of troxerutin are mediated through elastase inhibition

Abstract

Context

Obesity is a chronic low-grade inflammatory state associated with immune cell infiltration into the adipose tissue (AT). We hypothesize that the anti-obesity and anti-inflammatory effects of troxerutin (TX) are mediated through inhibition of elastase.

Objective

To determine the inhibitory effect of TX on elastase in vitro and in tumor necrosis factor alpha (TNFα) induced 3T3-L1 adipocytes and the molecular interaction of TX with human neutrophil elastase (HNE).

Materials and Methods

Differentiated 3T3-L1 adipocytes were pretreated with TX, elastatinal (ELAS) or sodium salicylate (SAL) before exposure to TNFα. Lipid accumulation, reactive oxygen species (ROS) generation and oxidant-antioxidant balance were examined. The mRNA and protein expression of TNFα, interleukin-6, monocyte chemoattractant protein-1, adiponectin, leptin, resistin, chemerin, and elastase were analyzed. Elastase inhibition by TX and ELAS in a cell free system and docking studies for HNE with TX and ELAS were performed.

Results

TX, ELAS or SAL pretreatment had lowered lipid droplets formation and TG content. TX suppressed ROS generation, oxidative stress and improved antioxidant status. The expression of inflammatory cytokines and elastase was downregulated while that of adiponectin was upregulated by TX. The concentration required to produce 50% inhibition in vitro (IC₅₀) was 11.5 μM for TX and 16.9 μM for ELAS. TX showed hydrogen bonding and hydrophobic interactions with elastase.

Discussion

TNFα induces inflammation of 3T3-L1 cells through elastase activation. TX inhibits elastase activity, downregulates expression and binds with elastase.

Conclusion

The antioxidant and anti-inflammatory activities of TX in AT could be of relevance in the management of obesity.

Keywords:

• Inflammation
• elastase
• obesity
• adipokines
• troxerutin
• 3T3-L1 cells

Acknowledgements

The authors acknowledge the Department of Science and Technology (DST), New Delhi, India for providing financial assistance to Ms. R. Vidhya under DST-PURSE phase II programme. The authors thank DST-FIST and UGC-SAP for the facilities provided in the Department of Biochemistry and Biotechnology, Annamalai University for executing this study.

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

One of the authors Ms. R. Vidhya received financial support in the form of Project Fellow from the Department of Science and Technology (DST)-PURSE, Phase II program (SR/PURSE Phase 2/25 (c) dated 16 January 2018), New Delhi, India.