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

Abstract

The ent kaurene diterpenoid, melissoidesin was isolated from the acetone extract of the leaves of Isodon wightii and the structure was designated as 3β, 11β, 15β-trihydroxy-6α-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 µg mL⁻¹. DPPH (1, 1-diphenyl-2-picrylhydrazyl) free radical scavenging activity of melissoidesin was significant and the IC₅₀ value was 138 µg 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 µg mL⁻¹, respectively. The 50% inhibitory concentration of melissoidesin on lipid peroxidation was calculated as 133 µg mL⁻¹. These findings indicate that ent kaurene diterpenoid, melissoidesin was promising antiacetylcholinesterase and antioxidant which can be used as food and drug preparations.

Keywords:

• Isodon wightii
• Melissoidesin
• Antiacetylcholinesterase activity
• DPPH
• Reducing power
• Hydroxyl radical scavenging
• Metal chelation
• Inhibition of lipid peroxidation

Acknowledgements

Thanks go to our colleagues Mr M. Manoj and P. Pitchai Department of Chemistry, Bharathiar University and Mr G. Mahendran, Department of Botany, Bharathiar University, Coimbatore, Tamil Nadu, India.