Ellagitannins are bioactive phenolic acids found in various fruits, plants, and beverages such as wine and spirits. This review aims to discuss the metabolism, absorption, and some health benefits related to the intestinal activity of these molecules, as well as some supplements developed from them. Ellagitannins are first biodegraded to ellagic acid and then to urolithins, which are more easily absorbed. This process is mediated by specific enzymes and intestinal microbiota. Not all individuals can metabolize ellagitannins into urolithins due to differences in the composition of the intestinal microbiota, resulting in three phenotypes: metabotypes A, B, and 0. In recent decades, ellagitannins and their derivatives (ellagic acid and urolithins) have gained significant attention for their potential benefits against various digestive diseases, including irritable bowel syndrome, peptic ulcers, gastritis, colon cancer, esophageal cancer, and pancreatic cancer. As a result, nutraceutical supplements have been developed to treat these conditions, representing significant and promising applications of these compounds in digestive health.

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.

Ellagitannins (ETs) derived from rambutan (Nephelium lappaceum L.) peel are polyphenols that have gained prominence in the food and nutraceutical industries due to their high bioactivity. The objective of this study was to evaluate the encapsulation efficiency (EE) of ETs obtained from rambutan peel in sodium alginate beads, as well as their effect on cell viability and antioxidant potential. ETs were extracted and semi-purified using Amberlite XAD-16 resin and identified by HPLC/ESI/MS. To determine the encapsulation efficiency, a 3^k Box–Behnken experimental design was employed, evaluating the influence of ET concentration (1000, 2000, and 3000 ppm), sodium alginate (1, 2, and 3%), and CaCl₂ (5, 10, and 15 mM). Cell viability was assessed in HEK-293 and 3T3 cell lines, and antioxidant potential was determined through ABTS, DPPH, and FRAP assays. The results showed a maximum EE of 55% under conditions of 3000 ppm ETs, 2% sodium alginate, and 5 mM CaCl₂. Cell viability assays confirmed that both the crude extract and the ET-loaded capsules possess excellent biocompatibility, maintaining values above 70%. Furthermore, the capsules demonstrated significant antioxidant potential (ABTS 76%, DPPH 65%, FRAP 1.11 mmol TE/L) compared to the control (sodium alginate). These findings position the ET-loaded rambutan peel capsules as a promising alternative for the development of functional products in the food industry.