Grayanotoxin I

Grayanotoxin I is a diterpene toxin that has been found in R. ponticum nectar, a component of mad honey. It increases resting sodium permeability in squid axonal membranes when used at a concentration of 10 µM. Grayanotoxin I (0.25, 0.5, and 1 mg/kg) induces proteinuria and reduces serum levels of alanine transaminase (ALT), also known as glutamic pyruvic transaminase (GPT), in rats. It also induces hepatic focal necrosis and central vein dilation in the same model when administered at a dose of 1 mg/kg. Grayanotoxin I is toxic to mice (LD50 = 1.31 mg/kg).