Pironetin is an α/β unsaturated lactone isolated from Streptomyces species. Pironetin binds to α-tubulin and is a potent inhibitor of microtubule polymerization, and has cell cycle arrest and antitumor activity^[1][2]. IC50 & Target: Microtubule^[1] In Vitro: Pironetin (20-100 ng/mL; 24 hours; 3Y1 cells) treatment arrests the cell cycle progression at G2/M in 3Y1 cells^[1].
Pironetin (1-10000 ng/mL; 3 days; HeLa, A2780 and K-NRK cells) treatment inhibits the cell proliferation. IC₅₀ values against these cell lines are almost 10 ng/mL^[1]. In Vivo: Pironetin (0.78-6.25 mg/kg; intraperitoneal injection; daily; for 5 days; female CDF1-SLC mice) treatment shows a moderate antitumor effect, however, a severe weight loss is observed as a side effect^[1].