Grayanane diterpenoids with diverse bioactivities from the roots of Pieris formosa

During our continuing study on the roots of Pieris formosa, twelve new grayanane diterpenoids (1-12), together with eight known compounds (13-20), were obtained. Their structures with absolute configurations were characterized by a series of spectroscopic methods and X-ray diffraction. Compounds 1, 2, 4-5, 7-8, 14, and 19 exhibited significant analgesic activity in an acetic acid-induced writhing test. In particular, 7 and 14 were found to be 5 times more potent than morphine in the acetic acid-induced writhing test model. Compounds 1, 4, 9, 13, and 18 showed antifeedant activity against Plutella xylostella at 0.5 mg/mL. Compound 4 exhibited a 38.3% inhibitory effect against the KCNQ2 potassium channel at a concentration of 10 mu M. (C) 2017 Elsevier Ltd. All rights reserved.