Antiacetylcholinesterase and antioxidant ent-kaurene diterpenoid, melissoidesin from Isodon wightii (Bentham) H. Hara

The ent kaurene diterpenoid, melissoidesin was isolated from the acetone extract of the leaves of Isodon wightii and the structure was designated as 3 beta, 11 beta, 15 beta-trihydroxy-6 alpha-acetoxy-ent-kaur-16-ene based on spectral data and previous reports. Melissoidesin isolated from the acetone extract of leaves showed potent antiacetylcholinesterase activity and the IC50 value was observed as 215 mu g mL(-1). DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging activity of melissoidesin was significant and the IC50 value was 138 fig mL(-1). The significant reducing property of the melissoidesin was stronger in high concentration. IC50 value of melissoidesin on hydroxyl radicals and metal chelation was observed as 99 and 143 mu g mL(-1), respectively. The 50% inhibitory concentration of melissoidesin on lipid peroxidation was calculated as 133 mu g mL(-l). These findings indicate that ent kaurene diterpenoid, melissoidesin was promising antiacetylcholinesterase and antioxidant which can be used as food and drug preparations.