Optimization of Supercritical Fluid Extraction and Microwave Assisted Extraction of Betulinic Acid From Dillenia Indica Bark Using Experimental Design

Abstract

The extraction of pharmacologically active constituent from plant sources can be carried out in various ways, such as maceration, reflux and soxhlet extraction. However, these conventional extraction methods are usually time consuming, solvent-consuming, incompatible with most thermo-labile compound and causes hazards to the environment. So, the simple, cost effective, time saving and sustainable technique was investigated in present work for the extraction of betulinic acid (BA) from bark of Dillenia indica (D. indica). D. indica is commonly known as „Karmal‟ belonging to family Dilleniaceae and usually found and collected from Dang forest of Gujarat. BA is one of the active phytoconstituent having varied pharmacological activities like anticancer, antidiarrheal, antimicrobial, ant ioxidant, anti-inflammatory and many more. Bark of D. indica is reported to contain BA in good amount. The objective of this study was to investigate the optimum extraction conditions for BA from D. indica bark by supercritical fluid extraction (SFE) and microwave assisted extraction (MAE) using response surface methodology (RSM) based on 3 factor 3 level Box- Behnken design (BBD). For SFE, BBD was performed to evaluate the combination effect of three independent variables, co-solvent concentration (2%, 5%, 10 %), extraction temperature (35°C, 50°C, 60°C) and extraction pressure (100bar, 150bar, 200bar). For MAE, the BBD was also applied with three different independent variables; extraction temperature (70°C, 80°C, 90°C), microwave power (100W, 150W, 200W) and extraction time (10 min., 15 min., 20 min.). Extraction of BA was performed by considering these parameters and quantified using developed HPTLC method. Maximum extraction of BA with SFE and MAE were found to be 0.69% and 0.91% at optimized experimental conditions; co-solvent concentration 10%, temperature 50°C, pressure 200bar and temperature 90°C, power 100W, time 15 min respectively. Analysis of variance showed that the “p-value” of SFE and MAE were 0.0141 and 0.0004 which indicate that the models were statistically significant (p˂0.05). The value of the “coefficient of determination” (R2) for SFE and MAE were 0.94 and 0.99 which indicate that the models show the goodness of fit. The study proves that the SFE and MAE are promising techniques for extraction and isolation of BA from D. indica bark and these techniques can be extended for the isolation of many important pharmacologically active phytoconstituent.