INS and fatty liver disease: In the context of type 2 diabetes and metabolic syndrome, catechins regulate blood glucose by improving insulin sensitivity and suppressing the expression of key gluconeogenic enzymes in the liver, as shown in Figure 3B,C; their antioxidant and anti-inflammatory actions alleviate adipose tissue inflammation, reduce hepatic steatosis and inflammation, improve insulin resistance, and promote fatty acid oxidation and energy metabolism via AMPK pathway activation.