1-Naphthohydroxamic acid (compound 2; 20-40 μM; 0-144 ?hours; BE(2)-C, SK-N-BE(2) and SH-SY5Y cells) treatment reduces cell numbers in a concentration-dependent manner.
1-Naphthohydroxamic acid (compound 2) at concentrations in the range of its in vitro IC ₅₀ against HDAC8 results in reduced cell density and outgrowth of neurite-like structures that stained positive for neurofilament.1-Naphthohydroxamic acid reduces the formation of clones in soft-agar concentration dependently.
When either cell type (HeLa and HEK293 cells) is treated with 1-Naphthohydroxamic acid (compound 2; 0.8 μM, 4 μM, 20 μM or 100 μM), only tubulin becomes hyperacetylated.

Dose-limiting toxicities (DLTs) of 1-Naphthohydroxamic acid (compound 2; 0-40 mg/kg; intraperitoneal injection; daily; for 10 day; NMRI Foxn1 nude mice) include weight loss and signs of liver toxicity, as evidenced by elevated plasma liver enzymes and detection of necrotic areas on histological liver examination. 1-Naphthohydroxamic acid has the maximum tolerable doses at 50?mg/kg per day. At these concentrations, neither body weight nor blood parameters are critically changed.
Pharmacokinetic studies after intraperitoneal administration of the inhibitors identified the half-life of 1-Naphthohydroxamic acid to be ~15?min, with a plasma peak concentration of ~30?μM.