A new method for preparing pentacyclic triterpene rich Centella asiatica extracts

Abstract

This study evaluated microwave-assisted extraction (MAE) for four pentacyclic triterpenes as well as developed a method for preparing a pentacyclic triterpenene rich extract from Centella asiatica. MAE was capable of increasing the yield of the pentacyclic triterpenes up to twice that produced by the heat reflux method, and it was also much less time consuming. The optimal conditions of MAE employed were extraction with absolute ethanol as solvent, an irradiation power of 600 W, at 75°C, four irradiation cycles and four extraction times. Here, we provide a simple method for the preparation of the pentacyclic triterpene rich C. asiatica extracts, which contained not less than 65% w/w total pentacyclic triterpenes. The method involved a macroporous resin (Diaion® HP-20) column eluted with ethanol and a decolourisation step with activated charcoal.

Keywords:

• Centella asiatica
• pentacyclic triterpenes
• microwave-assisted extraction
• macroporous resin
• antibacterial

Acknowledgements

The authors thank Thailand Research Fund through the Royal Golden Jubilee PhD Program (Grant no. PHD/0271/2551), Prince of Songkla University for support in the form of a research grant and Dr Brian Hodgson for his kindness in helping with the preparation of this article.