Alborixin

Alborixin is an ionophore originally isolated from S. albus that has diverse biological activities.^1,2,3,4 It is active against B. cereus, B. megaterium, S. lactis, S. aureus, and C. xerosis (MIC₅₀s = 0.4, <0.1, 0.8, 0.2, 0.8 mg/kg, respectively).^[1] Alborixin decreases the proliferation of eight cancer cell lines (IC₅₀s = 3.2 to 15.4 µM).^[2] It induces apoptosis, decreases the mitochondrial membrane potential, and increases the levels of reactive oxygen species (ROS) in HCT116 colon cancer cells when used at a concentration of 5 µM. Alborixin (1 mg/kg) increases heart rate, right ventricular contractile force, systolic and diastolic arterial blood pressure, and plasma levels of glucose in the coronary sinus and hepatic veins, as well as decreases the QT interval and plasma levels of potassium and sodium, but not calcium, in the coronary sinus and hepatic, renal, and deep femoral veins in normotensive dogs.^[3] It reduces the number of C. parvum oocytes in C. parvum-infected mice when administered at doses of 1.5 or 2.5 mg/kg.^[4] Alborixin is toxic to mice (LD₅₀ = 150 mg/kg).^[1]

References:
[1].Delhomme, C., Kergomard, A., Kergomard, G., et al.Alborixin, a new antibiotic ionophore: Taxonomy, isolation and biological propertiesJ. Antibiot. (Tokyo)29(7)692-695(1976).
[2].Shah, A.M., Wani, A., Qazi, P.H., et al.Isolation and characterization of alborixin from Streptomyces scabrisporus: A potent cytotoxic agent against human colon (HCT-116) cancer cellsChem. Biol. Interact.256198-208(2016).
[3].Moins, N., Gachon, P., and Duchene-Marullaz, P.Effects of two monocarboxylic ionophores, grisorixin and alborixin, on cardiovascular function and plasma cation concentrations in the anesthetized dogJ. Cardiovasc. Pharmacol.1(6)659-671(1979).
[4].Blagburn, B.L., Sundermann, C.A., Lindsay, D.S., et al.Inhibition of Cryptosporidium parvum in neonatal Hsd:(ICR)BR Swiss mice by polyether ionophores and aromatic amidinesAntimicrob. Agents Chemother.35(7)1520-1523(1991).