Bequinostatin A is a naphthoquinone originally isolated from Streptomyces and a glutathione S-transferase pi 1 (GSTP1) inhibitor (IC50 = 0.6 μg/ml for human GSTP1).1
References
1. Aoyama, T., Kojima, F., Abe, F., et al. Bequinostatins A and B new inhibitors of glutathione S-transferase, produced by Streptomyces sp. MI384-DF12. Production, isolation, structure determination and biological activities J. Antibiot. (Tokyo) 46(6),914-920(1993).