Rebeccamycin is an antitumor antibiotic+ inhibits DNA topoisomerase I. Rebeccamycin appears to exert its primary antineoplastic effect by poisoning topoisomerase I. It also has a negligible effect on protein kinase C and topoisomerase II.
L-Penicillamine is a medication primarily. It is used for the treatment of Wilson's disease. It is also used for people with kidney stones who have high urine cystine levels, rheumatoid arthritis, copper poisoning, and lead poisoning.
Emestrin is a mycotoxin originally isolated from E. striata that has antimicrobial, immunomodulatory, and cytotoxic activities.1,2,3,4,5 It is active against the fungi C. albicans and C. neoformans, as well as the bacteria E. coli, S. aureus, and methicillin-resistant S. aureus (MRSA; IC50s = 3.94, 0.6, 2.21, 4.55, and 2.21 μg ml, respectively).2 Emestrin is a chemokine (C-C motif) receptor 2 (CCR2) antagonist (IC50 = 5.4 μM in a radioligand binding assay using isolated human monocytes).3 Emestrin (0.1 μg ml) induces apoptosis in HL-60 cells.4 It induces heart, thymus, and liver tissue necrosis in mice when administered at doses ranging from 18 to 30 mg kg.5 |1. Seya, H., Nakajima, S., Kawai, K.-i., et al. Structure and absolute configuration of emestrin, a new macrocyclic epidithiodioxopiperazine from Emericella striata. J. Chem. Soc. Chem. Commun. 10, 657-658 (1985).|2. Herath, H.M.T.B., Jacob, M., Wilson, A.D., et al. New secondary metabolites from bioactive extracts of the fungus Armillaria tabescens. Nat. Prod. Res. 27(17), 1562-1568 (2013).|3. Herath, K.B., Jayasuriya, H., Ondeyka, J.G., et al. Isolation and structures of novel fungal metabolites as chemokine receptor (CCR2) antagonists. J. Antibiot. (Tokyo) 58(11), 686-694 (2005).|4. Ueno, Y., Umemori, K., Niimi, E.-c., et al. Induction of apoptosis by T-2 toxin and other natural toxins in HL-60 human promyelotic leukemia cells. Nat. Toxins 3(3), 129-137 (1995).|5. Terao, K., Ito, E., Kawai, K.-i., et al. Experimental acute poisoning in mice induced by emestrin, a new mycotoxin isolated from Emericella species. Mycopathologia 112(2), 71-79 (1990).
Brevetoxin B is a polyketide neurotoxin produced by Karenia species and other dinoflagellates. It binds to site 5 on the alpha subunit of voltage-gated sodium channels (IC50 = 15 nM) on neurons at the neuromuscular junction, causing the channel to open irreversibly at potentials more negative than normal, discharging action potentials repetitively. Brevetoxin B is ichthyotoxic at nanomolar concentrations and is responsible for an illness described as neurotoxic shellfish poisoning.