Median inhibitory concentration

ECso Median inhibitory concentration against target cells... 

ADME-tox absorption, distribution, metabolism, and excretion/toxicologic properties ECS0 median effective concentration IC50 median inhibitory concentration MIC minimum inhibitory concentration MLSMR Molecular Libraries Small Molecule Repository TAACF-NIAID Tuberculosis Antimicrobial Acquisition and Coordinating Facility/ National Institute of Allergy and Infectious Diseases... 

Ancorinosides A-D inhibited MTl-MMP, with median inhibitory concentrations of 440, 500, 370, and 180 p,g/mL respectively, and are an order of magnitude less potent than the known synthetic MMP inhibitor FN-439 (130)] 151,152]. A limited SAR study of the natural products and the aglycon of ancorinoside B indicated that it is the tetramic acid moiety that is responsible for the inhibitory activity of the ancorinosides. Indeed, tenuazonic acid (131), a natural product isolated from the fungus Altemaria tenuis [153] that has the tetramic acid unit as its only functionality, exhibited inhibitory activity against MTl-MMP and MMP2 comparable to FN-439 [151]. 

Finasteride and dutasteride are both mechanism-based inhibitors of type 1 and type 2 5a-reductase isoenzymes that inactivate 5a-reductase by an apparent irreversible modification of 5o-reductase (105,106). The inhibition constants (median inhibitory concentrations [ICsos]) in Table 45.5 suggest that finasteride is 30 times more selective for type 2 5a-reductase, whereas dutasteride appears to be approximately 10 times more potent as an inhibitor of type 2 5a-reductase than as a inhibitor of type 1 5a-reductase. The reduction of finasteride to dihydrofinasteride proceeds through an enzyme-bound, NADP-dihydrofinasteride adduct (see Chapter 5) (105). The mechanism- based inhibition explains the exceptional potency and specificity of finasteride and dutasteride in the treatment of BPH. This concept of mechanism-based inhibition may have application to the development of other inhibitors of pyridine nucleotide-linked enzymes. 

Normally, the toxicity of metal ions is described by measuring median lethal dose (LD50) values or median lethal concentration (LC50). However, some authors reported toxicities using IC50 (median inhibitory concentration) and EC50 (median eflective concentration) terms. LD50 values of some forms of metal ions are listed in Table 1.1 (The values are taken from the book Instrumental Methods in Metal Ion Spedation). 

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