Analgesic Grayanane-Derived Diterpenoids from the Flowers of .

Ten new grayanane-derived diterpenoids, rhodomollein LVII-LXVI (-), along with the known compound rhodomollein XLIII (), were isolated from the flowers of . Their structures were elucidated by detailed spectroscopic analysis, X-ray diffraction crystallography, and ECD calculations. Rhodomollein LVII-LIX (-) are the first-discovered 3----coumaroylquinic acid, nicotinic acid, and 2-furoic acid derivatives of grayanane diterpenoids, respectively. In an acetic acid-induced writhing test, compounds and demonstrated significant antinociceptive effects with writhing inhibition rates of 77.2% and 71.5%, respectively, at a dose of 0.2 mg/kg. Compound was found to be twice as potent as morphine, exhibiting significantly lower toxicity (LD = 130.90 mg/kg, i.p.) compared to rhodojaponin VI (LD = 1.79 mg/kg, i.p.).