Potencial efecto terapéutico de los polifenoles obtenidos de la cáscara de granada en la esteatosis hepática

RESUMEN Antecedentes: La enfermedad por hígado graso no alcohólico (EHGNA) tiene una elevada prevalencia a nivel mundial, y puede ir desde la esteatosis simple hasta hepatocarcinoma. Su origen es multifactorial, siendo la dieta poco saludable un factor clave en su patogenia y progresión. Los polifenoles son antioxidantes que han mostrado beneficios en el tratamiento de la EHGNA. Una fuente emergente de estos compuestos son los residuos agroindustriales, entre ellos, la cáscara de granada. La cáscara de granada tiene un alto contenido de polifenoles, específicamente de elagitaninos. Su extracto fenólico (extracto de cáscara de granada; ECG) ha mostrado efectos promisorios a nivel metabólico. Sin embargo, su uso presenta algunas limitantes que deben ser consideradas antes de recomendar su ingesta mediante alimentos funcionales o nutracéuticos para prevención o tratamiento de EHGNA. Objetivo: Discutir a partir de datos obtenidos en estudios in vitro y modelos animales, el potencial terapéutico de los polifenoles obtenidos de la cáscara de granada para prevención y tratamiento de la EHGNA. Metodología: Se realizó una búsqueda bibliográfica en bases de datos PubMed y Web of Science (2015 a la fecha) de estudios en modelos de esteatosis hepática in vitro y en animales, además de ensayos clínicos relacionados. Conclusión: Existen datos promisorios sobre el uso del ECG en alteraciones metabólicas propias de la EHGNA y esteatosis hepática, principalmente a nivel de perfil lipídico. Se deben discutir las dosis y formas de administración, con el fin de mejorar su estabilidad y biodisponibilidad. Se requieren ensayos clínicos controlados que confirmen los efectos en humanos.

ABSTRACT Background: Nonalcoholic fatty liver disease (NAFLD) has a high prevalence worldwide and can range from simple steatosis to hepatocarcinoma. Its causes are multifactorial, with an unhealthy diet being a key factor in its pathogenesis and progression. Polyphenols are antioxidants that have shown benefits in treating NAFLD. An emerging source of these compounds is agro-industrial by-products, including pomegranate peels. Pomegranate peels are high in polyphenols, specifically ellagitannins. Its polyphenolic extract (PPE) has shown promising metabolic benefits. However, its use has some limitations that must be considered before recommending its intake through functional foods or nutraceuticals to prevent or treat NAFLD. Objective: This article aims to discuss, using results from in vitro studies and animal models, the therapeutic potential of polyphenols obtained from pomegranate peels to prevent and treat NAFLD. Methods: A bibliographic search was carried out in PubMed and Web of Science databases (2015 to date) of in vitro and animal model studies of hepatic steatosis, in addition to related clinical trials. Conclusion: There are promising data on the use of PPE in metabolic disorders typical of NAFLD and hepatic steatosis, mainly improving lipid profile. Doses and vehicles of administration should be discussed to improve stability and bioavailability. Controlled clinical trials are required to confirm the effects in humans.

Study on the Inhibitory Mechanism of Pomegranate Peel Polyphenols on Human Prostate Cancer PC 3 Cells Ba- sed on Apoptosis and Autophagy Pathway / 中国药房

OBJECTIVE：To st udy the inhibitory mechanism of pomegranate peel polyphenols （PPP）on the proliferation of human prostate cancer PC 3 cells based on autophagy and apoptosis pathway. METHODS ：CCK-8 assay was used to investigate the effects of PPP with different concentrations （25-300 μg/mL）on PC 3 cell activity after culturing for 24，48，72 h，so as to screen the drug concentration and treatment time. PC 3 cells were divided into control group （complete culture medium ），PPP low- ，medium- and high-concentration groups. After treated for 48 h，flow cytometry and Annexin V-FITC/PI staining were used to detect cell cycle distribution and apoptosis of PC 3 cells. Western blotting assay was used to detect the expression of apoptosis-related protein as Bax ，Bcl-2，as well as the expression of autophagy-related proteins as LC 3，Beclin-1，p62，Atg12 and Atg 16. RESULTS ：The culturing time was chosen as 48 h. IC 50 of PPP was 110 μg/mL，and 50，100，200 μg/mL were chosen as low，medium，high concentrations of PPP. Compared with control group ，the percentage of PC 3 cells at phase G 0/G1 decreased significantly in PPP low- and medium-concentration groups while increased significantly at phase S ；that of PC 3 cells at phase G 0/G1 increased significantly in PPP high-concentration group ； while that of PC 3 cells at phase G 2/M decreased significantly in PPP medium- and high-concentration groups （P＜0.05 or P＜0.01）. The apoptosis rate of PC 3 cells was increased significantly in PPP groups （P＜ 0.05 or P＜0.01）. Compared with control group ，protein expression of anti-apoptosis protein Bcl- 2 and autophagy-related promoting protein p 62 were decreased in PPP groups to different extents ，while protein expression of promoting-apoptosis protein Bax as wells as autophagy-related protein LC 3-Ⅱ/LC3-Ⅰ ration and protein expression of Beclin- 1，Atg5，Atg12 and Atg 16 were increased to different extents ；there was statistical significance in above indexes in PPP high-concentration group and some of above indexes in PPP low- and medium-concentration groups （P＜0.05 or P＜0.01）. CONCLUSIONS ：PPP can inhibit the proliferation of human prostate cancer PC 3 cells，mechanism of which may be related to inducing autophagy and promoting apoptosis.

The Impact of Pomegranate Peel-fortified Cupcakes on Weight Loss

Pomegranate peel is considered as an antioxidant and a nutritive by-product. It is easily available after the production of pomegranatejuice. The purposes of the current research were to use the powder of pomegranate peel (PPP) as an antioxidant and a fibre-rich source tomake a nutritious cupcake based on 5%, 10%, 15% and 20% PPP and investigate its effect on the weight loss of rats fed by a high-fat diet(HFD). In total, 42 female albino adult rats were included and divided into 7 groups (each group contained 6 rats). A basal diet was fed toGroup 1 (G1) (negative control), a HFD was given to (G2), a HFD+ control cupcake was given to (G3), (G4) received a HFD + 5% PPPfortified cupcake, (G5) was fed a HFD + 10% PPP-fortified cupcake, (G6) was fed a HFD + 15% PPP-fortified cupcake and (G7) was feda HFD + 20% PPP-fortified cupcake. Food consumption, food efficiency, and body weight gain (g), the serum lipid profile and liverfunction were monitored. The results revealed a significant decline (p>0.05) in the weight gain of rats in G7 followed by G6, G5 and G4and compared to G2 and G3. VLDL-C, LDL-C, total cholesterol, triglycerides, and liver enzymes (AST, ALT) were decreased by increasingthe amount of PPP in the cupcake; whereas, HDL-C was increased significantly. In conclusion, pomegranate peel powder-fortifiedcupcakes can help with weight loss and avoid the risk of obesity, which could be incorporated into a range of foods.

Optimization of enzyme assisted extraction of polysaccharides from pomegranate peel by response surface methodology and their anti-oxidant potential / 中草药·英文版

Objective: To optimize the enzymatic extraction conditions of polysaccharides from pomegranate peel using response surface methodology (RSM), and invest the anti-oxidant activity of pomegranate peel polysaccharide in vitro for seeking novel biological components used as pharmaceutical products and functional foods. Methods: Effects of enzymolysis time, ratio of water to raw material, and the dosage of cellulase on the extraction yield of pomegranate peel polysaccharide were fully examined by Box-Behnken design of RSM. DPPH radical scavenging activity, hydroxyl radicals scavenging activity, superoxide anion radical scavenging activity, and reducing power assay were measured by microplate reader. Results: The optimal extraction conditions were as follows: enzymolysis temperature 55 °C, pH 5.0, enzymolysis time 88 min, ratio of water to raw material 22:1 mL/g, and dosage of cellulose 0.93%. Under the optimal extraction conditions, the yield of pomegranate peel polysaccharide was (22.31 ± 0.07)%, which was well matched with the predicted value 22.35% of the Box-Behnken design model. Also, pomegranate peel polysaccharide demonstrated appreciable anti-oxidant potential on DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging, hydroxyl radical scavenging, superoxide anion radical scavenging and reducing power in vitro. Conclusions: An optimized enzymolysis assisted method was proposed for the extraction of pomegranate peel polysaccharide, which can be used as a good anti-oxidant.

Optimization of Purification and Isolation of Punicalagin from Pomegranate Peel / 中国药师

Objective: To establish the methods for extraction and isolation of punicalagin from pomegranate peel, and further study the purification and quantification of punicalagin. Methods: Using an ultrasonic-assisted extraction method, punicalagin in pomegranate peel was extracted at room temperature by 50% ethanol with 20-fold volume of raw material. The content of punicalagin in the crude extract was determined by HPLC. To optimize the purification process of punicalagin, static adsorption and desorption experi-ments were employed to study five kinds of macroporous adsorbent resins (D101, A8-8, NKA-9, HPD-100 and HPD-500) for the one with the highest purification efficacy of punicalagin. In addition, the technical parameters of the macroporous adsorbent resin were opti-mized to obtain punicalagin with higher purity. Punicalagin was further separated and purified by using a reverse phase MCI GEL CHP20P column. Results:HPD500 resin showed the best ability to absorb and separate punicalagin in among five kinds of macro-porous adsorbent resins. The best technical parameters were as follows:the mass concentration of sample solution was 15 mg·ml-1 , the loading amount was 2BV, the pH was 2 and the eluting solvent was 8BV of 30% ethanol. With the best process as described a-bove, the content of punicalagin extracted from pomegranate peel increased from 10. 3% to 30. 7%. The obtained punicalagin could be further purified to 61. 3% from 30% in ethanol eluate by the reverse phase MCI GEL CHP20P column. Conclusion:HPD500 resin is the most effective in the purification of punicalagin from pomegranate peel, and the content of punicalagin can be dramatically increased after the purification by a reverse phase MCI GEL CHP20P column. The optimized process shows good reproducibility and stability.

Preliminary Analysis of Tannin-related Constituents in Pomegranate Peel by HPLC-ESI-MS / 中国药师

Objective:To identify the tannin-related constituents in the extracts of pomegranate peel by HPLC-ESI-MS. Methods:The separation was performed on a Kromasil C18 column (250 mm × 4. 6 mm,5 μm) with the mobile phase of water and acetonitrile. The flow rate was maintained at 1. 0 ml·min-1 and the detection wavelength was set at 256nm. The samples were analyzed in negative modes. Results:Five tannin-related constituents including gallic acid, punicalin,punicalagin,corilagin and ellagic acid were identified from the extracts of pomegranate peel. Conclusion:The new method is accurate and rapid. It can be used to identify the tannin-related constituents in pomegranate peel and provide new ideas for the research of active components in traditional Chinese medicine as well.

Single dose toxicity of polyphenols effective parts from Punica granatum and their protective effect on ethanol-induced gastric ulcer in rats / 中国药理学通报

Aims To study single dose toxicity of poly-phenols effective parts from Punica granatum,to eval-uate their safety,and thus to provide a theoretical basis for drug development and clinical use.To observe their protective effect on ethanol-induced gastric ulcer in rats.Methods 50 healthy Kunming mice were ran-domly divided into five groups and given different doses of polyphenols’effective parts from Punica granatum via intragastric administration.Toxicity and death in each group of mice were observed and recorded after administration for 14 d.The median lethal dose was calculated by Bliss method.70 rats were randomly di-vided into normal group,model group(constant volume of normal saline),sanjiuweitai particles(1 850 mg· kg-1 )group,colloidal bismuth subcitrate (33 mg · kg-1 )group and polyphenols effective parts from Puni-ca granatum low-dose,medium-dose,high-dose(430, 852,1 704 mg·kg-1 )groups.On the 9th day of 10 days’gavage,all except the normal group were fed ethanol (1.5 mL/only)to induce gastric mucosal inju-ry in rats with acute gastric ulcer.Gastric ulcer index, the rate of ulcer inhibition were calculated for each group.The morphological changes of gastric mucosa were observed.The gastric mucosa levels of PGE2 , NO,SOD and MDA were determined.Results The LD50 and 95%confidence limit of the polyphenols’ef-fective parts from Punica granatum were 8 520.9 mg· kg-1 and 7 291.2 ~9 914.4 mg·kg-1,respectively. Pathology showed that the organs receiving dose of 16 000 mg · kg-1 had different degrees of damage . Compared with the model group,the extract from Puni-ca granatum significantly repaired the gastric mucosa, and significantly increased the gastric mucosa levels of NO and reduced MDA content,and improved SOD content and the levels of PGE2 .Conclousion The dose of 5 063 mg · kg-1 of polyphenols effective part from Punica granatum showed no death.The dose of 16 000 mg · kg-1 of polyphenols effective parts from Punica granatum could cause varying degrees of dam-age in heart,liver,lung,kidney or the death of mice. The LD50 and 95% confidence limit of the polyphenols effective parts from Punica granatum were 8 520.9 mg ·kg-1 and 7 291.2 ~9 914.4 mg·kg-1,respective-ly.The extract from Punica granatum plays a protective role against gastric mucosa damage induced by absolute ethanol,and the mechanism may be related to promo-ting ulcer epithelial cells synthesis,enhancing mucosal regeneration function,regulating NO content and en-hancing antioxidant capacity.

Phenolic Constituents of Pomegranate Peels (Punica granatum L.) Cultivated in Oman.

Aims: This study was undertaken to analyze total phenolics and total flavonoids contents; and total antioxidant capacity of pomegranate peel extract and to identify the major functional components in the extract. Study Design: The extract was subjected to ESI-MS/MS. Place and Duration of Study: Department of Food Science and Nutrition, Sultan Qaboos University and DARIS Research Center, University of Nizwa, between December 2011 and August 2012. Methodology: Pomegranate peel extract was analyzed using a Waters Quattro Premier XE tandem quadrupole mass spectrometer (Waters Corporation, Manchester, UK) equipped with electro-spray ionization (ESI) source. Instrument control and data acquisition were performed using Mass Lynx ver. 4.1 software. The instrument was calibrated for nominal resolution for MS1 and MS2 up to 1200 m/z using the sodium caesium iodide standard calibration solution. Results: Results revealed high contents of total phenolics (64.2 mg Gallic acid equivalent/ g dry solids) and total flavonoids (1.4 mg Catechin equivalent/ g dry solids) respectively. Total antioxidant capacity ranged from 42.3 – 461.2 μmolTrolox equivalent/ g dry solids. The analysis revealed the presence of 61 different polyphenols in the extract among which 12 hydroxycinnamic acids, 14 hydrolysable tannins, 9 hydroxybenzoic acids, 5 hydroxybutanedioic acids, 11 hydroxy-cyclohexanecarboxylic acids and 8 hydroxyphenyls. Major compounds were tannins and flavonoids such as; illogic acid, gallic acids, punicalin, and punicalagin. Conclusion: A wide variety of phytochemicals present in pomegranate peel extract were identified. These functional compounds in pomegranate peels could be utilized by the food industry and pharma/nutraceutical’s industry. Further work should be done to isolate and quantify major functional compounds of pomegranate peels such as ellagic acid.

EFFECTS OF POMEGRANATE PEEL EXTRACTS ON ANTIOXIDANT CAPACITY AND LIPID METABOLISM IN HYPERLIPIDEMIC MICE / 营养学报

Objective: To investigate the effects of pomegranate peel extract on antioxidant capacity and lipid metabolism in C57BL/6J mice fed high fat diet in comparison with pomegranate juice extract. Method: The hyperlipidemic model was developed by feeding C57BL/6J mice a high fat diet. The effects of pomegranate peel extract (supplemented in drinking water) on serum FRAP value, paraoxonase(PON), GSH-Px and SOD activities as well as serum and hepatic lipids contents were observed. The morphologic change of aortic walls was also examined. Results: The antioxidant capacity and lipid metabolism were improved by supplementation of pomegranate peel extract in hyperlipidemic mice. The pathologic changes manifested in aortic walls were also inhibited. The pomegranate juice extract presented similar effects. Conclusion: The pomegranate peel extract inhibited the early process of atherosclerosis. The possible mechanisms were related to the improved antioxidant capacity and lipid metabolism.

STUDY ON EXTRACTION OF ANTIOXIDANTS IN POMEGRANATE PEEL AND ITS ANTIOXIDANT ACTIVITIES IN VITRO / 营养学报

Objective: To investigate the free radical scavenging activities of the extract from pomegranate peel and compare with that from juice. Methods: Free radicals (-2O, 稯H and ROO? scavenging activities were investigated in different special chemical systems. Its inhibition activity on LDL oxidation was studied with LDL oxidation model in vitro. Results:Both extracts had strong abilities to scavenge -2O, 稯H and ROO?radicals and prevent LDL oxidation in dose-dependent manner. The extract from peel showed higher activities than that from juice. Conclusion: The natural antioxidants in the extracts of pomegranate peel or juice can effectively scavenge -2O, 稯H and ROO?radicals, and prevent LDL oxidation significantly, especially much more in the former.