Benastatin B is a polyketide synthase-derived benastatin that has been found inStreptomycesand has diverse biological activities.^1,2,3It inhibits glutathione S-transferase (GST; K_i= 3.7 µM for the rat liver enzyme).²Benastatin B also inhibits the transglycosylase activity ofA. baumannii,C. difficile,E. coli, andS. aureusrecombinant penicillin-binding proteins (PBPs; IC₅₀s = 16, 53.3, 30.7, and 31.6 µM, respectively).³It is active against several bacteria, including methicillin-resistantS. aureus(MRSA; MIC = 3.12 µg/ml).²

1.Xu, Z., Schenk, A., and Hertweck, C.Molecular analysis of the benastatin biosynthetic pathway and genetic engineering of altered fatty acid-polyketide hybridsJ. Am. Chem. Soc.129(18)6022-6030(2007) 2.Aoyagi, T., Aoyama, T., Kojima, F., et al.Benastatins A and B, new inhibitors of glutathione S-transferase, produced by Streptomyces sp. MI384-DF12. I. Taxonomy, production, isolation, physico-chemical properties and biological activitiesJ. Antibiot. (Tokyo)45(9)1385-1390(1992) 3.Wu, W.-S., Cheng, W.-C., Cheng, T.-J.R., et al.Affinity-based screen for inhibitors of bacterial transglycosylaseAm. Chem. Soc.140(8)2752-2755(2018)