Telomestatin is an inhibitor of the telomerase, it induces the formation of basket-type G-quadruplex (G4) structures from hybrid-type G-quadruplexes in the telomeric region.
Almestrone (developmental code names Ba 38372, Ciba 38372), also known as 7α-methylestrone, is a synthetic, steroidal estrogen which was synthesized in 1967 but was never marketed. It is used as a precursor in the synthesis of several highly active steroi
17β-hydroxy Exemestane is the primary active metabolite of exemestane . It is formed by metabolism of exemestane by the cytochrome P450 (CYP) isoforms CYP1A and CYP4A11. 17β-hydroxy Exemestane is an aromatase inhibitor (IC50 = 69 nM using human placental microsomes) and an androgen receptor (AR) agonist (IC50 = 39.6 nM) that is selective for AR over estrogen receptor α (ERα; IC50 = 21.2 μM). It stimulates growth of AR- and ERα-positive MCF-7 (EC50 = 2.7 μM) and T47D breast cancer cells (EC50s = 0.43 and 1,500 nM for AR- and ER-mediated growth, respectively) and inhibits proliferation of testosterone-treated aromatase-overexpressing MCF-7aro cells in a concentration-dependent manner. 17β-hydroxy Exemestane (20 mg/kg) inhibits increases in serum cholesterol and LDL levels and prevents decreases in bone mineral density in the lumbar vertebrae and femur, as well as femoral bending strength and compressive strength of the fifth lumbar vertebrae, in ovariectomized rats.
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).