Synthesis and Cytotoxic Properties of New Substituted Glycosides-Indole Conjugates as Apoptosis Inducers in Cancer Cells

Background & Objective: Glycosyl heterocycles, being as nucleoside analogs with modified glycon and hybrid heterocycle motifs, are of considerable interest, and thus, the targeted compounds were synthesized via a convenient and efficient approach. Methods: New indolyl-thiadiazolyl thioglycosides scaffolds were synthesized, starting with the reaction of indole-3-carbaldehyde with 2-aminothiadiazole-5-thiole followed by glycosylation and deprotection. Likewise, new molecular hybrids comprising indole, thiadiazole, triazole and glycosyl moieties were synthesized utilizing click chemistry strategy. The cytotoxic activities of the newly synthesized compounds were studied on colon carcinoma HCT116, breast carcinoma MCF-7, lung carcinoma A549 and hepatocellular carcinoma HepG2 cell lines using Sulphorhodamine-B (SRB) assay. Results: The 1,3,4-thiadiazole thioglycoside and the 1,2,3-triazole N¹-glycoside possessing xylose moiety, compounds 8 and 15 revealed the most potent bio-activity among the new chemical entities; therefore, they undertook for further analysis of apoptosis. Conclusion: IC50s of Compound 8 were 38, 36, 33 and 158μg/ml, while they were 41, 44, 32 and 25μg/ml for compound 15 on HepG2, MCF7, HCT116 and A549 cell lines, respectively; furthermore, the total apoptosis rate (%) for control untreated cells were 9.63, 28.4, 25.4 (%), compounds 8 and 15 respectively, they produced a significant increase in total and early apoptosis rate (%) compared to control (P=0.0001). At the same time, no significant difference was detected in the late apoptosis rate (%), which means that both derivatives have the potential to be developed into potent anticancer agents.