Characterization of pomegranate peel extracts obtained using different solvents and their effects on cell cycle and apoptosis in leukemia cells.

Pomegranate (Punica granatum L.) has been used in traditional herbal medicine by several cultures as an anti-inflammatory, antioxidant, antihyperglycemic, and for treatment and prevention of cancer and other diseases. Different parts of the fruit, extraction methods, and solvents can define the chemical profile of the obtained extracts and their biological activities. This study aimed to characterize the chemical profile of peel extracts collected using different extraction solvents and their biological effects on the cell cycle and apoptosis of THP-1 leukemic cells. Aqueous extract presented the highest content of punicalagins (α pun = 562.26 ± 47.14 mg/L and ß pun = 1,251.13 ± 22.21 mg/L) and the lowest content of ellagic acid (66.38 ± 0.21 mg/L), and it promoted a significant impairment of the cell cycle S phase. In fact, punicalagin-enriched fraction, but not an ellagic acid-enriched fraction, caused an S phase cell cycle arrest. All extracts increased the number of apoptotic cells. Punicalagin-enriched fraction increased the percentage of cells with fragmented DNA, which was intensified by ellagic acid combination. The treatment combining punicalagin and ellagic acid fractions increased the apoptotic cleaved PARP1 protein and reduced the activation of the growth-related mTOR pathway. Thus, these results evidence that solvent choice is critical for the phenolic compounds profile of pomegranate peel extracts and their biological activities.

Storage stability of the phenolic compounds, color and antioxidant activity of jambolan juice powder obtained by foam mat drying.

Jambolan (Syzigium cumini (L.) Skeels) stands out among the Brazilian fruits that are rich in bioactive compounds with potential for the production of dehydrated product. Therefore, jambolan juice powder was produced by foam mat drying method and stored for 150 days at three temperatures (4, 25, 35 °C). The effect of time, temperature and the interaction of these two factors on the qualitative and quantitative profile of phenolic compounds were determined after analysis of the powders by using HPLC-DAD-ESI-MSn. For the powders submitted to the different study condition, the concentration of flavonols did not differ from the control sample, and only a small reduction in the anthocyanins concentrations was seen (7-9%), only being significantly affected by storage time. Additionally, the molar profiles of these compounds were influenced more by time than storage temperature, however none of the compounds identified was totally degraded. The percentages of antioxidant activity oscillated during the storage time, however, without major losses after 150 days at all storage temperatures. The results showed that jambolan juice powder is very stable in terms of anthocyanins and flavonols concentrations at all three temperatures of the storage. This and the attractive color (purplish-red) make it a potential ingredient to enrich differentiated foods.

Combining pressurized liquids with ultrasound to improve the extraction of phenolic compounds from pomegranate peel (Punica granatum L.).

The combination of ultrasound and pressurized liquid extraction (UAPLE) was evaluated for the extraction of phenolic compounds from pomegranate peels (Punica granatum L.). The influence of several variables of the process on extraction yield, including solvent type (water, ethanol + water 30, 50 and 70% v:v), temperature (50-100 °C), ultrasound power (0-800 W at the generator, or 0-38.5 W at the tip of the probe), mean particle size (0.68 and 1.05 mm), and number of cycles (1-5), were analyzed according to the yield of 20 different phenolic compounds. The most suitable temperatures for the extraction of phenolic compounds using water were from 70 to 80 °C. In general, 100 °C was not adequate since the lowest extraction yields were observed. Results suggested that ultrasound had a greater impact on extraction yields using large particles and that intermediate ultrasound power (480-640 W at the generator, or 23.1-30.8 W at the tip of the probe) produced the best results. Using small particles (0.68 mm) or large particles (1.05 mm), extraction with ultrasound was 1 cycle faster. Ultrasound may have offset the negative effect of the use of large particles, however, did not increase the yield of phenolic compounds in any of the cases studied after five cycles. Additionally, the continuous clogging problems observed with small particles were avoided with the use of large particles, which combined with ultrasound allowed consistent operation with good intra and inter-day reproducibility (>95%). Using samples with large particle size, the best extraction conditions were achieved with water extraction solvent, 70 °C extraction temperature, ultrasound power at 480 W, and 3 cycles, yielding 61.72 ±â€¯7.70 mg/g. UAPLE demonstrated to be a clean, efficient and a green alternative for the extraction of phenolic compounds from pomegranate peels. These findings indicate that UAPLE has a great potential to improve the extraction of bioactive compounds from natural products.