In vitro activity: Tofogliflozin is the potent and most selective inhibitor of SGLT2; the selectivity of tofogliflozin toward SGLT2 is 2900 times that toward SGLT1. Tofogliflozin dose-dependently inhibited glucose entry into tubular cells, tofogliflozin suppressed high glucose-induced ROS generation, MCP-1 gene induction and apoptosis in tubular cells and an antioxidant NAC mimicked the effects of tofogliflozin on high glucoseexposed tubular cells

Kinase Assay: Tofogliflozin (also known as CSG-452) hydrate is a novel, very potent and highly selective inhibitor of sodium/glucose cotransporter 2 (SGLT2) with Ki values of 2.9, 14.9, and 6.4 nM for human, rat, and mouse respectively. Tofogliflozin competitively inhibited SGLT2 in cells that overexpress SGLT2. The selectivity of tofogliflozin towards human SGLT2 versus human SGLT1, SGLT6, and sodium/myo-inositol transporter 1 is the highest among the tested SGLT2 inhibitors under clinical trials. Long-term inhibition of renal SGLT2 by tofogliflozin not only preserved pancreatic beta-cell function, but also prevented kidney dysfunction in a mouse model of type 2 diabetes. These findings suggest that long-term use of tofogliflozin in patients with type 2 diabetes may prevent progression of diabetic nephropathy.

Cell Assay: Tubular cells are treated with or without 3 nM or 30 nM tofogliflozin under serum-free BM containing 10 μg/ml transferrin and GA-1 000 for 24 h at 37 °C. Then, the cells are washed with PBS and incubated with Hanks’ balanced salt solution (HBSS) containing 100 μM of 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-d-glucose (2-NBDG), a fluorescent derivative of glucose, in the absence of tofogliflozin for 15 min. Culture medium is removed and replaced with HBSS, and fluorescence intensity in the cells is analyzed in an ARVO fluorescent plate reader.