LeuRS-IN-1 is a highly potent and orally active inhibitor of the leucyl-tRNA synthetase enzyme derived from Mycobacterium tuberculosis (M.tb LeuRS). It exhibits significant inhibitory activity against M.tb LeuRS with IC 50 and Kd values of 0.06 μM and 0.075 μM, respectively. Additionally, LeuRS-IN-1 effectively inhibits human cytoplasmic LeuRS with an IC 50 value of 38.8 μM and suppresses protein synthesis in HepG2 cells with an EC 50 value of 19.6 μM.

LeuRS (Human cytoplasmic):38.8 μM (IC50), LeuRS (M. tuberculosis):0.06 μM (IC50), LeuRS (M. tuberculosis):0.075 μM (Kd), Protein synthesis (HepG2 cells):19.6 μM (EC50)

LeuRS-IN-1 (compound 13) has a MIC value of 0.02 μg/mL for M.tb H37Rv bacteria[1]. LeuRS-IN-1 (compound 3a) (48 h) induces HepG2 cell toxicity with an EC 50 value of 65.8 μM[2].

LeuRS-IN-1 (100 mg/kg; orally daily for 14 days) reduces lung CFU value in acute tuberculosis (TB) mice[1]. LeuRS-IN-1 (33 mg/kg; orally 5 days a week for 4 weeks) reduces lung and spleen CFU values in chronic TB mice[1]. Murine pharmacokinetic parameters[1]: Administration Dose (mg/kg) C max (μg/ml) at 5 min CL (ml/h/kg) V ss (ml/kg) MRT (h) AUC 0-∞ (h · μg/ml) α-t 1/2 (h) (% AUC) β-t 1/2 (h) (% AUC) i.v. 30 13.6 582 3,142 5.4 51.6 0.10 (2) 3.83 (98) Administration Dose (mg/kg) C max (μg/ml) T max (h) AUC 0-24 (h · μg/ml) Terminal t 1/2 (h) Bioavailability (%) (h · μg/ml) Mouse PPB (%) p.o. 30 6.4 0.25 47.5 3.1 9.2 23 Animal Model: Murine GKO (C57BL/6-Ifngtm1ts) model of acute TB[1]Dosage: 100 mg/kg Administration: Orally daily for 14 days after 10 days of infection (start) with M. tuberculosis Erdman. Result: Reduced lung CFU value in mice. Animal Model: Murine BALB/c model of chronic TB infection[1]Dosage: 33 mg/kg Administration: Orally 5 days a week for 4 weeks after infection with M. tuberculosis Erdman with a low-dose aerosol 21 days prior (start). Result: Reduced lung and spleen CFU values in mice.