The optimization of the extraction process of flavonoids from fermented chamomile ligulate flowers

Response surface methodology (RSM) was applied in order to examine the influence of extraction parameters on the extraction yield of total phenols (TP), total flavonoids (TF) and apigenin (A) from autofermented chamomile ligulate flowers (A-CLF) extracts. Temperature, the ethanol concentration and extraction time were selected as independent variables, and their values were selected on the basis of preliminary experimental results and literature data. The Box-Behnken experimental design which was applied consisted of 17 experimental runs with five replicates at the central point. A second-order polynomial model was used for predicting the response. Defined optimal conditions for maximizing yields of TP, TF and A included the extraction temperature of 80°C, ethanol concentration of 62% and extraction time of 50.4 min, whereas the maximum yields of apigenin could be expected at the temperature of 73.6°C, the solvent concentration of 60.8% and the extraction time of 46 min. The verification of the experimental process was done at previously defined optimal conditions. The experimental values agreed with those predicted thus indicating suitability of the used model and the success of RSM in optimizing the extraction conditions.