SUPERCRITICAL CARBON DIOXIDE EXTRACTION OF MELATONIN FROM BRASSICA CAMPESTRIS: IN VITRO ANTIOXIDANT, HYPOCHOLESTEROLEMIC AND HYPOGLYCAEMIC ACTIVITIES OF THE EXTRACTSAbstract
Brassica campestris Linn. (yellow mustard), a common Indian condiment, possesses melatonin as an important antioxidant. Optimization of supercritical carbon dioxide extraction (SC-CO2) process parameters was conducted to obtain an extract having the best combination of yield of melatonin and maximum in vitro hypoglycaemic and hypocholesterolemic activities, along with a desirable balance of ω6 to ω3 fatty acids. A full factorial design and response surface methodology were employed for process optimization. Melatonin content of the extracts was obtained by high performance liquid chromatography and by liquid chromatography-mass spectrometry. The optimized extraction conditions were obtained at 300 bar, 50 °C for 120 min. This extract exhibited highest content of melatonin (660.72±41.05 ng/g of dry mustard powder), maximum in vitro hypocholesterolemic (60.11±3.89%) and hypoglycaemic (59.70±2.67µg/ml) activities and possessed minimum ω6 to ω3 (1.29) ratio with minimum erucic acid content (2.00±0.20 g/100g of fatty acid). The electron paramagnetic resonance spectroscopy of the extract (0.10±0.001 g/ml) showed 72.10±4.01% scavenging activity of DPPH radicals, establishing its strong antioxidant potency. A new Chrastil equation was developed to compute solubility of melatonin in SC-CO2 under different extraction conditions. The SC-CO2 extract of yellow mustard seeds could have promising use as a natural source of melatonin as well as of balanced ω6 to ω3 fatty acids.
S. Chakraborty and P. Bhattacharjee
Department of Food Technology and Biochemical Engineering, Jadavpur University, Kolkata, West Bengal, India.
28 November, 2016
17 January, 2017
17 February, 2017
01 June, 2017