Flavonoids: Nutraceuticals for Rheumatic Diseases via Targeting of Inflammasome Activation

Abstract

Inflammation, an innate immune response that prevents cellular damage caused by pathogens, consists of two successive mechanisms, namely priming and triggering. While priming is an inflammation-preparation step, triggering is an inflammation-activation step, and the central feature of triggering is the activation of inflammasomes and intracellular inflammatory protein complexes. Flavonoids are natural phenolic compounds predominantly present in plants, fruits, and vegetables and are known to possess strong anti-inflammatory activities. The anti-inflammatory activity of flavonoids has long been demonstrated, with the main focus on the priming mechanisms, while increasing numbers of recent studies have redirected the research focus on the triggering step, and studies have reported that flavonoids inhibit inflammatory responses and diseases by targeting inflammasome activation. Rheumatic diseases are systemic inflammatory and autoimmune diseases that primarily affect joints and connective tissues, and they are associated with numerous deleterious effects. Here, we discuss the emerging literature on the ameliorative role of flavonoids targeting inflammasome activation in inflammatory rheumatic diseases.

Keywords: anti-inflammatory; flavonoids; inflammasomes; nutraceuticals; rheumatic diseases.

Figure 1

Ameliorative role of flavonoids in rheumatic diseases by inhibiting inflammasome activation. Icariin, procyanidin B2, trans-Chalcone, HMC, procyanidins, morin, EGCG, ferulic acid, and catechin play an anti-inflammatory role and alleviate GA in GA animal models and macrophages. Baicalein, icariin, procyanidin B2, and EGCG play an anti-inflammatory role and alleviate LN in lupus animal models and MDSCs. Quercetin and naringenin play anti-inflammatory roles and alleviate RA in RA animal and cell models. HMC, hesperidin methylchalcone; EGCG, epigallocatechin-3-gallate; GA, gouty arthritis; LN, lupus nephritis; RA, rheumatoid arthritis.