Optimization of Polyphenols and Carotenoids Extraction from Leaves of Cassia auriculata for Natural Health Products

Abstract

Aims: C. auriculata leaves contains polyphenols and carotenoids and also it posses various antioxidant activities towards free radical scavenging, lipid peroxidation inhibition and reducing potential. The present study investigated the optimization of polyphenols and carotenoids extraction from Cassia auriculata leaves by response surface methodology (RSM). Study Design: A three-factor, three-levels central composite design (CCD) was performed to determine the effect of solvent concentration (30-100%), extraction temperature (30-60°C) and extraction time (30-90 min) to obtain the best extraction parameters. Place and Duration of Study: Fresh C. auriculata leaves were collected from home gardens in Makandura area of Sri Lanka and the experiments were conducted at the Department of Food Science and Technology of Wayamba University of Sri Lanka between June 2016 and August 2016. Methodology: Total polyphenol and carotenoid contents of the ethanolic extracts of the C. auriculata leaves were determined. Total polyphenols and carotenoids content in the extracts were used as the response variables.  According to the design used, twenty randomized experiments including six replicates as the center points were assigned based on the combinations of extraction variables used CCD and the values of independent process variables considered, as well as response variables. The optimal value of these factors was determined suing response surface methodology. Predicted values were compared with experimental values. Results: The optimum extraction conditions for phenolics and carotenoids were 45.4% ethanol; 19.8°C; 110.5 min and 100% ethanol; 70.2°C; 9.5 min respectively. The optimal predicted contents for total polyphenols and carotenoids were 13.08 mg GAE/g-DW and 17.31 mg/g-DW respectively. Validation experiments results had good agreement with the predicted responses by RSM. Conclusion: Ethanol concentration was the most significant factor affecting on total polyphenols and carotenoids extraction. Extraction temperatures and time did not significantly influence on carotenoids and polyphenols extraction from leaves of C. auriculata.  The estimated optimum extraction conditions; were established and they were very close to the experimental values. These parameters can be used as the guidelines for scale-up extraction of bioactives from the leaves of C. auriculata.