A cell-permeable, stable free radical that is commonly used to evaluate the ability of compounds to act as free radical scavengers or hydrogen donors and to measure the antioxidant activity of tissue extracts; followed by color change from purple (absorbance at 515-528 nm) to yellow.

A pyrimadine analog that irreversibly inhibits thymidylate synthase, blocking the synthesis of thymidine which is required for DNA synthesis; widely used to treat many gastrointestinal tract adenocarcinomas.

A natural type B trichothecene produced by certain species of the fungus Fusarium; inhibits protein biosynthesis, binds to peptidyl transferase, and inhibits the synthesis of RNA and DNA; passes the blood-brain barrier at different rates in different animals.

A glutamine analog that inhibits glutaminases (Ki = 6 µM) and other glutamine-utilizing enzymes, including cytidine triphosphate synthase.

A selective non-peptide inhibitor of CXCR2, inhibiting IL-8 binding to CXCR2 (IC₅₀ = 22 nM).

Produced in fungi, including yeast, and invertebrates from ergosterol in response to ultraviolet radiation; metabolized first to 25-hydroxyvitamin D2 and subsequently to the active 1,25-dihydroxyvitamin D2.

An intermediate in the pathway leading to the production of 1,25-dihydroxy vitamin D3; plasma or serum levels are commonly used as an indicator of an individual’s vitamin D status.

An inhibitor of protein synthesis in eukaryotes (IC₅₀ = 5-50 μM) that functions by interfering with translational elongation; can either induce or inhibit apoptosis depending on cell type.

A central nervous system modulator that is used to experimentally induce seizures in animals; used extensively to screen for compounds that block the production of nonconvulsive (absence or myoclonic) seizures.

A noncompetitive nicotinic acetylcholine receptor antagonist with preferential activity at the α3β4 subtype (IC₅₀ = 90-640 nM) compared to α4β2, α3β2, and α7 subtypes (IC₅₀s range from 1-7 μM).

An intermediate produced from vitamin D2 by cytochrome P450 isoforms in vertebrates; subsequently metabolized to 1,25-dihydroxy vitamin D2, which is an agonist for the vitamin D receptor.

An orally active broad spectrum antifungal agent that blocks ergosterol biosynthesis by inhibiting the fungal CYP isoform CYP51; potently inhibits the mammalian analog CYP51A1 (IC₅₀ = 63.5 nM), as well as a variety of other CYP isoforms.

An analog of wortmannin; irreversibly binds PI3K; inhibits recombinant PI3K and mTOR (IC₅₀ = 2.7 and 193 nM, respectively) and prevents the growth of LNCap cells (IC₅₀ = 1.46 μM).

An NSAID commonly used in animals to combat pain and inflammation, particularly as associated with osteoarthritis; inhibits both COX-1 and COX-2 (IC₅₀s = 22.3 and 3.9 µM, respectively) and also FAAH (IC₅₀ = 74 µM).

An agonist of α2 adrenergic receptors (Ki = 194 nM); used for sedation, anesthesia, and analgesia in non-human mammals.

A cyclic polypeptide-containing anticancer antibiotic that binds to DNA and blocks transcription by interfering with RNA synthesis; ~10 nM promotes cell death in a variety of tumors.

Intended for use as an internal standard for the quantification of diclofenac by GC- or LC-MS.

A dihydropyridine L-type calcium channel antagonist that displays antihypertensive and antianginal activity; selectively inhibits adenosine A3 receptors (Ki = 3.25 µM) and CYP3A4 catalytic activity (IC₅₀ = 0.148 µM); activates TRPA1 channels, producing an increase in Ca2+…

A toxin produced by cyanobacteria that inhibits the catalytic activity of protein phosphatases PP1C, PP1γ, and PP2A with Ki values of 0.15, 0.24, and 0.018 nM, respectively.

A potent, selective antagonist of TRPV4 channels, blocking the influx of calcium induced by the TRPV4 agonist GSK634775 with IC₅₀ values of 2, 5, and 40 nM for rat, mouse, and human isoforms, respectively; effective in vivo, as it resolves pulmonary edema resulting from myocardial…

An irreversible inhibitor of carnitine palmitoyltransferase 1, a mitochondrial enzyme involved in fatty acid β-oxidation (IC50 = 5-20 nM in rat liver); also acts as a direct agonist of PPARα.

A polypeptide antibiotic effective against Gram-negative bacteria, including P. aeruginosa, A. baumannii, and K. pneumoniae.

A selective inhibitor of ABHD6 (IC₅₀ = 10 nM) with negligible activity against other serine hydrolases such as DAGLβ; used both as a probe to study ABHD6 and as a negative control for studies of DAGLβ.

A natural fungal metabolite which reversibly interferes with protein trafficking and secretion mediated by the Golgi apparatus and endoplasmic reticulum; directly and reversibly inhibits Sec7 domain-containing GEFs which are necessary for Arf activation associated with vesicular transport (IC50 =…

An amino-amide anesthetic that binds to the intracellular portion of voltage-gated sodium channels and blocks sodium influx into nerve cells, preventing the generation of an action potential; inhibits the uptake of dopamine in striatal synaptosomes by 47% at 100 µM.

A neurotoxin that binds to 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; ichthyotoxic at nanomolar concentrations.

Aminopterin is a folic acid analog and derivative of pterin; it is very similar to methotrexate in structure. Aminopterin exhibits anticancer chemotherapeutic and immunosuppressive activities. Like other folic acid analogs, aminopterin inhibits dihydrofolate reductase, depleting nucleotide pools…

An indole diterpene which potently and reversibly inhibits large conductance Ca2+-activated K+ (BKCa) channels, as shown in patch clamp (Ki = 1.9 nM) and whole smooth muscle cell studies (Ki = 35.7 nM).

A small molecule inhibitor of tankyrase 1 and 2 (IC₅₀ = 11 and 4 nM, respectively); increases the protein levels of the axin-GSK3β complex and promotes the degradation of β-catenin; inhibits colony formation of APC-deficient colorectal cancer cells at 0.33 µM.

Pargyline is an irreversible inhibitor of monoamine oxidase (MAO) that is used clinically to treat moderate hypertension. At 10 mg/kg iv, pargyline induces a moderate decrease of systolic blood pressure in unanaesthetized hypertensive rats but not normotensive WKR or Sprague-Daley rats. The…

PGE1 is the theoretical COX metabolite of DGLA, but it is virtually undetectable in the plasma of normal humans or other animals. Its pharmacology includes vasodilation, hypotension, and anti-platelet activities. The IC₅₀ of PGE1 for the inhibition of ADP-induced human platelet…

A colchicine derivative that inhibits tubulin polymerization (IC₅₀ = 2.1 μM) with low toxicity; suppresses microtubule dynamicity, inhibits cell migration, blocks microtubule assembly, and arrests cells in metaphase; used to synchronize cells and for karyotyping in cytogenetic studies.