Butein

Butein is a cAMP-specific PDE inhibitor with an IC₅₀ of 10.4 μM for PDE4^[1]. Butein is a specific protein tyrosine kinase inhibitor with IC₅₀s of 16 and 65 μM for EGFR and p60^c-src in HepG2 cells^[2]. Butein sensitizes HeLa cells to Cisplatin through AKT and ERK/p38 MAPK pathways by targeting FoxO3a^[3]. Butein is a SIRT1 activator (STAC). In Vitro: Butein potently inhibits cAMP-specific phosphodiesterase (type IV) activity with an IC₅₀ of 10.4±0.4 μM. In contrast, phosphodiesterase I, III and V activities were inhibited by Butein above 100 μM^[1].
Butein, a plant polyphenol, is a specific protein tyrosine kinase inhibitor. Butein inhibits not only the EGF-stimulated auto-phosphotyrosine level of EGFR in HepG2 cells but also tyrosine-specific protein kinase activities of EGFR (IC₅₀=16 μM) and p60^c-src (IC₅₀=65 μM) in vitro^[2].
Butein (10, 20, and 40 μM; 24, 48, and 72 hours) inhibits cell growth in a dose- and time-dependent manner^[3].
Butein exhibits anticancer activity through the inhibition of the activation of PKB/AKT and MAPK pathways, which are two pathways known to be involved in resistance to cisplatin. Butein (20 µM) decreases phosphorylation of AKT, ERK and p38 following 24 h of co-treatment with Cisplatin (20 µM)^[3]. In Vivo: Butein (2 mg/kg every 2 days) in combination with Cisplatin (2 mg/kg every 2 days) for 3 weeks suppresses tumor growth in vivo^[3].