Process optimization for microwave assisted extraction of Foeniculum vulgare Mill using response surface methodology

Abstract

Present study was aimed to optimize the microwave assisted extraction (MAE) of phytochemicals from Foeniculum vulgare Mill and its comparison with other conventional extraction methods. Biological activities of polar and nonpolar extracts (from MAE, Soxhlet and cold maceration) were also compared. For this purpose, seed powder of Foeniculum vulgare Mill was extracted by Microwave assisted extraction (MAE), Soxhlet extraction (SE) and Cold maceration (CM) using water as a solvent. MAE conditions (power level, time of microwave irradiation and particle size of plant matrix) for maximum phenolic content from F. vulgare, were optimized using central composite design (CCD) of response surface methodology. Thereafter, antioxidant activities and reducing power of all extracts was analyzed and compared. Nonpolar fractions of extracts were analysed with GCMS. Results showed that MAE gave higher extracts from F. vulgare in 4 min as compared to 20 and 24 h of SE and CM respectively. MAE extracted smaller particle size (40 µ) more efficiently while extraction yield of other two techniques was not significantly affected by particle size of seed powder. Optimal extraction conditions were found to be 600 W, 3 min and 80 µm of particle size. Antioxidant potential of MAE extracts was also higher (75.5%), comparable to the standard antioxidants used. Extracts were then fractionated into chloroform and n-hexane fractions and were subjected to GCMS analysis and antibacterial activity. On comparison it was concluded that both the fractions of MAE gave the maximum variety of nonpolar constituents and enhanced antibacterial activity. MAE proved to be a rapid and energy efficient method for plant based extractions for polar as well as non-polar components from F. vulgare without affecting their biological activities. In conventional herbal industry, MAE protocols can replace maceration and SE, to save time, energy and cost as well. This will also reduce the final cost of the medicine at consumer level Keywords: Antioxidants, Foeniculum vulgare, Medicinal plants, Microwave assisted extraction, Phenolics, Phytochemicals