PF-04447943 is a potent, selective brain penetrant PDE9 inhibitor (Ki of 2.8, 4.5 and 18 nM) for human, rhesus and rat recombinant PDE9 respectively and high selectivity for PDE9 versus PDEs1-8 and 10-11.

5,7-Diacetoxy-8-methoxyflavone is a natural product isolated and purified from the roots of Scutellaria baicalensis.

HA130 是一种选择性自毒素 (ATX) 抑制剂，IC50 为 28 nM。

N-Methylbenzamide is a potent phosphodiesterase 10A (PDE10A) inhibitor. N-Methylbenzamide has anti-cancer activity.

Ensifentrine is an inhaled first-in-class dual inhibitor of phosphodiesterase 3 (PDE3) and PDE4 with IC50s of 0.4 nM and 1479 nM, respectively.

MY-5445 is a specific inhibitor of cyclic GMP phosphodiesterase 5 with IC50 of 0.5 μM.

Nortadalafil is demethyl tadalafil, which is a PDE5 inhibitor, currently marketed in pill form for treating erectile dysfunction (ED) and pulmonary arterial hypertension.

DSR-141562 is a novel orally available and brain-penetrant PDE 1 inhibitor. It has preferential selectivity for predominantly brain-expressed PDE1B over other PDE1 family members, and high selectivity for the PDE1 family over other PDE families and 65 other tested biologic targets.

ITI-214 is a picomolar PDE1 inhibitor with excellent selectivity against other PDE family members and against a panel of enzymes, receptors, transporters, and ion channels, exhibits potent PDE1 inhibitory activity (Ki = 58 pM).

Irsogladine is a PDE4 inhibitor and muscarinic acetylcholine receptor binder.

(S)-C33 is a potent PDE9 inhibitor with IC50 of 11 nM.

D 159687 is selective inhibitor of PDE4B and PDE4D with brain permeability.

CP-671,305 is a potent and selective PDE4D inhibitor.

ICI 63197 is a potent phosphodiesterase (PDE) 4 inhibitor with antidepressant effects.

3-O-Methylquercetin, a natural product isolated and purified from the herbs of Croton cascarilloides with antiviral, anti-inflammatory and bronchodilating effects, is a selective and competitive PDE3/PDE4 inhibitor, and inhibits PDE3 than PDE4 with a low K(m) value. 3-O-Methylquercetin also inhibits total cAMP- and cGMP-phosphodiesterase (PDE) of guinea pig trachealis at low concentrations.

Sophoflavescenol is a prenylated flavonol, which shows great inhibitory activity with IC50 of 13 nM against phosphodiesterase 5 (PDE5), and also inhibits RLAR, HRAR, AGE, BACE1, AChE and BChE with IC50s of 0.30 μM, 0.17 μM, 17.89 μg/mL, 10.98 μM, 8.37 μM and 8.21 μM, respectively.

Zardaverine is a dual-selective PDE3/4 inhibitor with IC50 values of 0.5 μM and 0.8 μM respectively.