Novel natural and synthetic inhibitors of solute carriers SGLT1 and SGLT2

Abstract

Selective analogs of the natural glycoside phloridzin are marketed drugs that reduce hyperglycemia in diabetes by inhibiting the active sodium glucose cotransporter SGLT2 in the kidneys. In addition, intestinal SGLT1 is now recognized as a target for glycemic control. To expand available type 2 diabetes remedies, we aimed to find novel SGLT1 inhibitors beyond the chemical space of glycosides. We screened a bioactive compound library for SGLT1 inhibitors and tested primary hits and additional structurally similar molecules on SGLT1 and SGLT2 (SGLT1/2). Novel SGLT1/2 inhibitors were discovered in separate chemical clusters of natural and synthetic compounds. These have IC₅₀-values in the 10-100 μmol/L range. The most potent identified novel inhibitors from different chemical clusters are (SGLT1-IC₅₀ Mean ± SD, SGLT2-IC₅₀ Mean ± SD): (+)-pteryxin (12 ± 2 μmol/L, 9 ± 4 μmol/L), (+)-ε-viniferin (58 ± 18 μmol/L, 110 μmol/L), quinidine (62 μmol/L, 56 μmol/L), cloperastine (9 ± 3 μmol/L, 9 ± 7 μmol/L), bepridil (10 ± 5 μmol/L, 14 ± 12 μmol/L), trihexyphenidyl (12 ± 1 μmol/L, 20 ± 13 μmol/L) and bupivacaine (23 ± 14 μmol/L, 43 ± 29 μmol/L). The discovered natural inhibitors may be further investigated as new potential (prophylactic) agents for controlling dietary glucose uptake. The new diverse structure activity data can provide a starting point for the optimization of novel SGLT1/2 inhibitors and support the development of virtual SGLT1/2 inhibitor screening models.

Keywords: SGLT1; SGLT2; diabetes; glucose; inhibitors; screening.

Figure 1

FCFP6‐PCA visualization of chemical space occupied by the Spectrum Collection compound library and chemical clusters with novel SGLT1/2 inhibitors. A, Chemical space visualization of the Spectrum Collection compound library and clusters of additional structurally similar molecules with PC1‐3 of the FCFP6‐PCA. Detected SGLT1/2 inhibitors in the clusters are indicated with ■, other cluster compounds with ●. SGLT1/2 inhibitors exist outside the chemical space of the phloridzin–containing glycosides cluster. B, Zoomed in image of A. C, Molecular clusters obtained with a Dice FCFP6 similarity algorithm. PC1‐3 of the FCFP6‐PCA explained 14% of intercompound differences. For the complete datasets of the PCA and Dice FCFP6 analyses, see Table S2

Figure 2

Compounds from different chemical clusters show varying inhibition of SGLT1 and SGLT2. Representative compounds per cluster are ranked from highest to lowest SGLT1 inhibitory activity at 50 μmol/L. For each compound x in a cluster the similarity to the central cluster compound c is indicated ( S_xc(%)). Clusters in order of increasing activity are: A, glycosides (natural), (B) angular pyranocoumarins (APC, natural), (C) trimipramine‐like (synthetic), (D) diphenhydramine‐like (synthetic), (E), trihexyphenidyl‐like (synthetic), (F) bupivacaine‐like (synthetic), (G) quinidine‐like (natural), (H) viniferin‐like (natural). Results are means with SD from n biological replicates of two technical replicates, as indicated in Table S2. For means of n = 2 biological replicates SDs are used indicatively. + = original dataset for this compound contained a statistical outlier which was excluded from calculation of the mean and SD

Figure 3

Inhibition of ¹⁴C‐α‐methylglucose uptake and transcellular transport by Caco‐2 cells by (+)‐pteryxin and Peucedanum praeruptorum extract containing (+)‐pteryxin. A, Inhibition of ¹⁴C‐α‐methylglucose cellular uptake and transcellular transport by (+)‐pteryxin and P p.‐extract. Results are means with SD from 2 biological replicates, each consisting of four technical replicates. VC = vehicle control. B, 700 MHz 1D ¹H‐NMR spectra of (+)‐pteryxin (top) and P p.‐extract (bottom) dissolved in CDCl₃ (298K). Characteristic signals from (+)‐pteryxin are annotated in both spectra using triangles, indicating the presence of (+)‐pteryxin in the P p.‐extract