Antioxidant and Anticholinesterase Activity Evaluation of ent-Kaurane Diterpenoids from Sideritis arguta

Abstract

The petroleum ether and acetone extracts of the aerial parts of Sideritis arguta afforded two new and six known diterpenoids with the ent-kaurane skeleton. The structures of the new diterpenoids were determined as ent-7 alpha,18-diacetoxy-16 beta-hydroxykaurane (diacetyidistanol) (1) and ent-7 alpha-acetoxy,15 alpha,18-dihydroxykaur-16-ene (15-epi-eubol) (2) by spectroscopic data interpretation. Antioxidant potential was investigated for the ent-kauranes and the plant extracts by three methods (beta-carotene bleaching, free-radical scavenging, and superoxide-anion scavenging activity). Acetylcholinesterase and butyrylcholinesterase inhibitory activity were also evaluated, and the ent-kauranes eubol (3), sideroxol (5), and 7-epi-candicandiol (6) exhibited moderate butyrylcholinesterase inhibitory activity.