Capsaicin is the primary active component of the heat and pain-eliciting lipid-soluble fraction of the Capsicum pepper. Capsaicin is present in natural hot pepper extracts along with a number of impurities, including dihydrocapsaicin and several lesser impurities. Separation by HPLC is required in…

A cyclododecadepsipeptide potassium-selective ionophore antibotic; induces apoptosis in several cell tyes, including CHO cells, by stimulating potassium efflux.

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).

A polymethoxylated flavone that has been shown to enhance adipogenesis and lipolysis, to inhibit α-glucosidase and α-amylase activity, and to suppress the expression of genes associated with inflammation by regulating IκBα.

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 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.

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…

A neuroexcitatory amino acid that functions as a NMDA and metabotropic glutamate receptor agonist; used to induce brain lesions in animal models of cognitive dysfunction.

A selective allosteric inhibitor of Bcr-Abl (IC₅₀s = 4.52, 0.38, and 0.93 µM against Bcr-Abl mutants G250E, E255V, and M351T, respectively); displays additive inhibitory activity against T315I Bcr-Abl mutants both in in vitro assays and in a recalcitrant T315I Bcr-Abl mutant mouse…

A non-selective COX inhibitor with IC₅₀ values for ovine COX-1 and -2 of 0.1 and 6 µM, respectively; IC₅₀ values for human recombinant COX-1 and -2 are 1.67 and 24.6 µM, respectively.

A cyanobacterial toxin that targets protein and glutathione synthesis in hepatocytes (IC50s = 1.3 and 2.4 µM, respectively), inhibits uridine monophosphate synthase complex activity (Ki = 10 µM), and induces DNA damage.

A potent uncoupler of oxidative phosphorylation in mitochondria that disrupts ATP synthesis by transporting protons across cell membranes.

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

Myriocin is an amino fatty acid antibiotic derived from certain thermophylic fungi, in this case Mycelia sterilia. It is a potent immunosuppressant having 10- to 100-fold more activity than cyclosporin A. Myriocin is a potent inhibitor of serine palmitoyltransferase (Ki = 0.28 nM), the enzyme that…

An analog of 1,24-dihydroxy vitamin D3 which, when used in a 4 μg/g ointment, suppresses psoriasis; inhibits the growth of both normal and psoriatic human keratinocytes (IC50 ~ 10 nM) via the vitamin D receptor; suppresses the production of RANTES and IL-8 by human dermal fibroblasts.

A dihydropyridine L-type calcium channel blocker that selectively inhibits calcium influx in cardiac and vascular smooth muscle; inhibits calcium-induced contractions in depolarized rat aorta (IC₅₀ = 1.9 nM), displaying a slow rate of association and dissociation in isolated vascular and…

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.

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 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 tricyclic antidepressant that inhibits the reuptake of serotonin and norepinephrine and acts as an antagonist at histamine, serotonin, adrenergic, and muscarinic receptors with Ki values in the nanomolar range.

A dipyridinyl compound that demonstrates high in vitro and ex vivo selectivity for COX-2 over COX-1.

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 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.

A benzothiazole derivative with anti-excitotoxic effects that acts by blocking the presynaptic release of glutamate, indirectly antagonizing glutamate receptors, and inactivating neuronal voltage-gated Na+ channels (ED50 = 2.3 μM); suppresses glutamate-induced seizures in rats (ED₅₀ =…

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 alkaloid that inhibits the growth of mouse leukemia P388 cells (IC₅₀ = 1.8 μg/ml); binds to and stabilizes the topoisomerase I-DNA binary complex, leading to DNA breakage and cell death (IC₅₀ = 5.07-12.6 μM); selectively inhibits CYP1A1 and CYP1A2 (IC50 = ~6 μM for…

A nitrogen mustard β-chloro-nitrosourea compound used as an alkylating agent to form interstrand crosslinks in DNA, which leads to cancer cell cytotoxity and apoptosis; also reported to inhibit glutathione reductase, thioredoxin reductase, and lipoamide dehydrogenase.

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…

An antibacterial and coccidiostat compound that shows selective toxicity for HMLER breast cancer stem cells (IC₅₀ = ~24 μM); 8 μM treatment of 4T1 and MCF-7-Ras breast cancer cell lines decreases cancer stem cell growth ~2-fold and ~3-fold, respectively; 5 mg/kg inhibits mammary…

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 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…

A flavonoid compound found in the bark and rinds of many plants and fruits.