Table I.

Mechanisms of four typical flavonoids to improve insulin resistance

Flavonoid name	Mechanism to improve insulin resistance
Baicalin	Hypoglycemic (GLUT4), lowers lipids, lowers insulin, anti-inflammatory (IL-1β, TNF-α, IL-6), anti-oxidative (GSH, SOD), improves skeletal muscle IR (AMPK/Akt/GSK-3β), liver IR (CaMKKβ/AMPK/ACC, PPAR-γ), induces autophagy
Baicalein	Lowers blood sugar, lowers lipids (cleaves caspase-3), protects pancreatic β-cells and promotes secretion, anti-inflammatory (TNF-α, IL-1β, IL-6), inhibits SOCS3 and GSK3β, increases IRS1 and AKT1, regulates MAPK/PI3K/AKT signaling pathway
Quercetin	Reduces blood sugar and lipids, anti-inflammatory (TLR4/NF-κB, TNF-α, IL-1β, IL-6), improves liver IR (PI3K/AKT/NF-κB, ADPN, AdipoR2)
Rutin	Anti-oxidative (SOD, GSH-Px, MDA, CAT), anti-inflammatory (TNF-α), affects insulin signaling pathway (PFK, PDH, Akt, GLUT4), improves endoplasmic reticulum stress (PDI, IRE1α), improves liver IR (PEPCK, PGC-1α), improves fat IR (P-Aktser473, P-AMPK), improves liver cells (PPAR-α, DGAT)