Optimization of solvent-free microwave extraction of Centella asiatica using Taguchi method

Abstract

Centella asiatica (C. asiatica) is a common herb found in the Indian subcontinent, Southeast Asia, and wetland regions of the Southern US. Although it grows abundantly in these regions, very few reports are available on the modern extraction of C. asiatica, especially by the solvent-free microwave extraction (SFME) method. In this study, the process parameters (microwave power, extraction time, vacuum and stirrer) affecting SFME of asiaticoside from C. asiatica were optimized by the Taguchi method. Here, the vacuum was identified as the primary factor that contributes to the level of yield followed by microwave power, extraction time and stirrer. The highest amount of asiaticoside detected in the C. asiatica extract was 158.8 μg ml−1. The extraction carried out at optimized conditions for the confirmatory study was found to produce 0.38 % of more extract yield than the highest yield obtained in the test runs of Taguchi design, thereby supporting the accuracy of optimization of process parameters under the given set of experimental conditions.