INS and type 2 diabetes mellitus: An important study by Ahn et al. (2002[3]) shows that 1,2-NQ inhibits PTP1B (protein tyrosine phosphatase 1B), a major negative regulator of insulin signaling, which plays an important role in the development of diabetes type 2 (Ahn et al., 2002[3]; Kennedy and Ramachandran, 2000[21]).