Ultrasound-Assisted Extraction Optimization and Flash Chromatography Fractionation of Punicalagin from Pomegranate Peel (Punica granatum L.)

Background: Pomegranate peel (Punica granatum L.) is a rich source of phenols, particularly ellagitannins, highlighting punicalagin, a bioactive compound with recognized antioxidant potential. However, efficient recovery and purification methods are required to enable its application in food and health-related products. This study aimed to obtain a partially purified fraction of punicalagin from pomegranate peel using optimized extraction and purification strategies. Methods: A Taguchi L9 (3)3 experimental design was employed to optimize ultrasound-assisted extraction, evaluating extraction time (10, 20, 30 min), ethanol concentration (20, 40, 80%), and solid-to-solvent ratio (1:12, 1:14, 1:16). Total polyphenol content was quantified using the Folin–Ciocalteu method. Extracts obtained under optimized conditions were concentrated by rotary evaporation and subjected to semipurification using flash chromatography with Amberlite XAD-16 resin. Subsequently, the fractions were lyophilized and analyzed by HPLC/ESI/MS. Results: The Statistica software determined the optimal conditions for polyphenol extraction (20 min, 40% ethanol, 1:12), with the signal-to-noise (S/N) ratio reaching 88.43 ± 0.66, surpassing the predicted value of 77.42. Flash chromatography yielded four fractions, and HPLC/ESI/MS analysis revealed the presence of ellagitannins in all of them, with fraction number 2 showing the highest relative abundance of punicalagin (89.25%). Conclusions: The combination of ultrasound-assisted extraction and flash chromatography proved effective for obtaining punicalagin-rich fractions from pomegranate peel, supporting its potential for nutraceutical applications.