1,2,3-triazole tethered Indole-3-glyoxamide derivatives as multiple inhibitors of 5-LOX, COX-2 & tubulin: Their anti-proliferative & anti-inflammatory activity

Abstract

To evaluate the role of COX-2 and 5-LOX as dual inhibitors in controlling the cancer cell proliferation, a set of two series having 42 compounds of 1, 2, 3-Tethered Indole-3-glyoxamide derivatives were synthesized by employing click chemistry approach and were also evaluated for their in vitro cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX) inhibitory activities with in vivo anti-inflammatory and in vitro anti-proliferative potencies. Among the compounds tested, compounds 11q and 13s displayed excellent inhibition of COX-2 (IC₅₀ 0.12 µM) with good COX-2 selectivity index (COX-2/COX-1) of 0.058 and 0.046 respectively. Compounds 11q and 13s also demonstrated comparable 5-LOX inhibitory activity with IC₅₀ 7.73 and 7.43 µM respectively to that of standard Norhihydroguaiaretic acid (NDGA: IC₅₀ 7.31 µM). Among all the selected cell lines, prostate cancer cell line DU145 was found to be susceptible to this class of compounds. Among all the tested compounds, compounds 11g, 11i, 11k, 11q, 13r, 13s and 13u demonstrated excellent to moderate anti-proliferative activity with IC_50s ranging between 6.29 and 18.53 µM. Compounds 11q and 11g demonstrated better anti-proliferative activities against DU145 cancer cell line with IC₅₀ values 8.17 and 8.69 µM respectively when compared to the standard drug etoposide (VP16; IC₅₀ 9.80 µM). Compounds 11g, 11k, 11q, 13s and 13u showed good dual COX-2/5-LOX inhibitory potentials with excellent anti-proliferative activity. Results from carrageenan-induced hind paw edema demonstrated that compounds 11b, 11l, 11q and 13q exhibited significant anti-inflammatory activity with 69-77% inhibition at 3 h, 75-82% inhibition at 5 h when compared to the standard drug indomethacin (66.6% at 3 h and 77.94% at 5 h). Ulcerogenic study revealed that compounds 11q and 13q did not cause any gastric ulceration. In vitro tubulin assay resuted that compound 11q interfered with microtubulin dynamic and act as tubulin polymerization inhibitor. In silico molecular docking studies demonstrated that compounds 11q and 13s are occupying the colchicines binding site of tubulin polymer and 11q illustrated very good binding affinities towards COX-2 and 5-LOX.

Keywords: 1,2,3-triazoles; 5-LOX; Anti-proliferation; COX-1; COX-2; Indole-3-glyoxamide derivatives; Tubulin.