Benzimidazole derivatives protect pancreatic β-cells against cytokine-induced apoptosis

This study describes the synthesis of a series of benzimidazoles 1-30 by treating 1,2-phenylenediamines with aromatic aldehydes. To further investigate the potential of benzimidazole derivatives in safeguarding the INS-1E β-cell line against apoptosis induced by cytokines, the cellular ATP levels were measured after 48 h of incubation with a cytokine cocktail of IL-1b, INF-c, and TNF-a. Eight out of thirty derivatives demonstrated protection against cytokine effects compound 7 exhibiting significant restoration of β-cell ATP levels. Structure-activity relationship (SAR) analysis revealed that hydroxyl and methoxy groups on the phenyl ring influenced activity, with a parallel arrangement of both groups showing the highest activity. Additionally, the position of these groups played a crucial role, with the ortho position being favorable. Compounds 7, 13, and 25 exhibited excellent to moderate activity, containing hydroxyl and methoxy groups in the ortho position and a fluoro group at position 6 of the fused benzimidazole moiety. Further analysis showed that compounds reducing nitrite production in the presence of cytokines also restored glucose-stimulated insulin secretion (GSIS). Compounds 7, 13, and 25 emerged as the most potent derivatives, displaying dose-dependent increases in cellular ATP levels, inhibition of caspase-3 activity, decreased nitrite production, and restored glucose-stimulated insulin secretion (GSIS). These findings suggest the potential of benzimidazoles in protecting pancreatic β-cells against cytokine-induced apoptosis, warranting further investigation into their specific mechanisms and potential use as antidiabetic agents.