IN VITRO INHIBITION OF PROTEIN TYROSINE PHOSPHATE 1B BY APIGENIN

Protein Tyrosine Phosphatase 1B (PTP1B) is a key regulatory enzyme involved in insulin and leptin signaling and has been strongly associated with the development of metabolic disorders such as type 2 diabetes and obesity. These conditions continue to rise globally, posing serious public health challenges. This study aimed to evaluate the in vitro inhibitory potential of apigenin, a natural flavonoid, on PTP1B, with the goal of exploring its therapeutic relevance in metabolic disease management. The study employed purified PTP1B enzyme, para-nitrophenyl phosphate (pNPP) as the substrate, and varying concentrations of apigenin. The inhibitory effect of apigenin on PTP1B was assessed by measuring enzyme activity spectrophotometrically at 405 nm. The results revealed a concentration-dependent inhibition, with significant reduction in enzyme activity at higher apigenin concentrations. Kinetic analysis using Michaelis-Menten and Lineweaver-Burk plots showed a marked decrease in Vmax while Km values remained relatively unchanged. This pattern indicates that apigenin functions as a competitive inhibitor, interacting directly with the enzyme’s active site to limit substrate access. These findings confirm that apigenin is a potent inhibitor of PTP1B and support its potential as a natural therapeutic agent for the treatment of metabolic disorders. The study provides strong evidence for the enzyme-targeting capabilities of apigenin and lays the groundwork for future in vivo studies aimed at validating its clinical applicability.