Design of experiment approach for the process optimisation of microwave assisted extraction of lupeol from Ficus racemosa leaves using response surface methodology.
BACKGROUND
Triterpenoids are a group of important phytocomponents from Ficus racemosa (syn. Ficus glomerata Roxb.) that are known to possess diverse pharmacological activities and which have prompted the development of various extraction techniques and strategies for its better utilisation.


OBJECTIVE
To develop an effective, rapid and ecofriendly microwave-assisted extraction (MAE) strategy to optimise the extraction of a potent bioactive triterpenoid compound, lupeol, from young leaves of Ficus racemosa using response surface methodology (RSM) for industrial scale-up.


METHODS
Initially a Plackett-Burman design matrix was applied to identify the most significant extraction variables amongst microwave power, irradiation time, particle size, solvent:sample ratio loading, varying solvent strength and pre-leaching time on lupeol extraction. Among the six variables tested, microwave power, irradiation time and solvent-sample/loading ratio were found to have a significant effect (P < 0.05) on lupeol extraction and were fitted to a Box-Behnken-design-generated quadratic polynomial equation to predict optimal extraction conditions as well as to locate operability regions with maximum yield.


RESULTS
The optimal conditions were microwave power of 65.67% of 700 W, extraction time of 4.27 min and solvent-sample ratio loading of 21.33 mL/g. Confirmation trials under the optimal conditions gave an experimental yield (18.52 µg/g of dry leaves) close to the RSM predicted value of 18.71 µg/g.


CONCLUSIONS
Under the optimal conditions the mathematical model was found to be well fitted with the experimental data. The MAE was found to be a more rapid, convenient and appropriate extraction method, with a higher yield and lower solvent consumption when compared with conventional extraction techniques.
Pharmacognosy and Phytotherapy Research Laboratory, Division of Pharmacognosy, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
Anup Kumar
AK
Das
Vivekananda
V
Mandal
Subhash C
SC
Mandal
D000975:Antioxidants / Q000302:isolation & purification / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000737:chemistry; D005591:Chemical Fractionation / Q000379:methods*; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D030681:Ficus / Q000737:chemistry*; D008872:Microwaves; D053978:Pentacyclic Triterpenes / Q000302:isolation & purification* / Q000494:pharmacology; D010851:Picrates / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry*; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D000094042:Lupanes
D000975:Antioxidants; D001713:Biphenyl Compounds; D053978:Pentacyclic Triterpenes; D010851:Picrates; D012997:Solvents; C004931:1,1-diphenyl-2-picrylhydrazyl; C010480:lupeol; D000094042:Lupanes