Synthesis, biological evaluation and in silico study of bis-thiourea derivatives as anticancer, antimalarial and antimicrobial agents

Two sets of bis-thioureas including a para series (8–14) and a meta series (4, 5, 15–19), were synthesized and evaluated for their anticancer, antimalarial and antimicrobial activities. Most of the synthesized bis-thioureas, except for analogs 8–11, displayed cytotoxicity against MOLT-3 cell line (IC50 = 1.55–32.32 µM). Derivatives 5, 14, 18 and 19 showed a broad spectrum of anticancer activity. Analogs (4, 5, 8, 13, 14, 18 and 19) exhibited higher inhibitory efficacy in HepG2 cells than the control drug, etoposide. Significantly, bis-trifluoromethyl analog 19 was the promising potent cytotoxic agent (IC50 = 1.50–18.82 µM) with the best safety index (1.64–20.60). Antimalarial activity results showed that trifluoromethyl derivative 18 was the most potent compound (IC50 = 1.92 µM, selective index = 6.86). Antimicrobial activity revealed that bis-thioureas 12, 18 and 19 exhibited selective activity against Gram-positive bacteria and fungi. Promisingly, the bis-trifluoromethyl derivative 19 was the most potent compound in the series and displayed higher potency, against most of the Gram-positive bacteria and fungi, than that of ampicillin, the reference drug. Among the tested strains of microorganisms, compound 19 inhibited the growth of Staphylococcus epidermidis ATCC 12228 and Micrococcus luteus ATCC 10240 with the lowest MIC of 1.47 µM. The findings demonstrated that trifluoromethyl group plays a crucial role in their biological activities. Furthermore, the molecular docking was performed to reveal possible binding modes of the compounds against target proteins.