Optimization of Extraction Conditions of Pomegranate Peel Polyphenols and Its Protective Effect on Acute Alcoholic Liver Injury in Mice

[Objectives]This study was conducted to explore the optimization of ultrasonic-assisted organic solvent extraction of pomegranate peel polyphenols(PPPs),and to study the protective effect of PPPs on acute alcoholic liver injury in mice.[Methods]The optimal extraction conditions of PPPs were determined by single factor and orthogonal experiments,and an acute alcoholic liver injury model in mice was established.Bifendate was used as the positive control group to investigate the protective effect of low,medium and high doses of PPPs on acute alcoholic liver injury.[Results]The optimum extraction process parameters were followed as 60%ethanol concentration,solid-liquid ratio of 1:40(w/v),extraction temperature of 50℃,and extraction time of 1.5 h,and the yield was 1.42%.The results of animal experiments showed that PPPs could effectively reduce the degree of alcoholic liver injury in mice,reduce the levels of serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST),and reduce the inflammation and necrosis of liver tissue in mice.Meanwhile,the total polyphenols from pomegranate peel also significantly reduced the expression levels of malondialdehyde(MDA),tumor necrosis factor(TNF-α)and interleukin-6(IL-6)in mice,and increased the levels of superoxide dismutase(SOD)and reduced glutathione(GSH)in liver tissue of mice,indicating its antioxidant and anti-inflammatory effects,further illustrating its protective effect on alcoholic liver injury.[Conclusions]PPPs could reduce the expression levels of TNF-α,IL-6 and MDA in mice,and increase the expression levels of SOD and GSH to achieve the protective effect on acute alcoholic liver injury in mice.This study will provide new ideas for the development of new anti-alcoholic liver injury drug resources.

Pomegranate peel polyphenols alleviate insulin resistance through the promotion of insulin signaling pathway in skeletal muscle of metabolic syndrome rats

Insulin resistance(IR) has been considered to be an important causative factor of metabolic syndrome(Met S). The present study investigated whether pomegranate peel polyphenols(PPPs) could prevent the development of Met S by improving IR in rats. Male Sprague-Dawley(SD) rats were fed high fat diet(HFD) to induce Met S and supplemented with different dosages of PPPs for 12 weeks. The results showed that HFD-induced insulin resistant rats had disordered metabolism of blood glucose, blood lipid, and terrible muscle fiber morphology when compared with normal diet-fed rats, but PPPs treatment at a dosage of 300 mg/kg·day significantly reversed these negative effects. Moreover, in skeletal muscle tissue of insulin resistant rats, PPPs treatments significantly increased the protein expressions of insulin receptor(Ins R) and phosphorylated insulin receptor substrate 1(IRS-1), stimulated peroxisome proliferator activated receptor gamma(PPARγ) and phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT/PKB) signaling pathway, and aggrandized the protein levels of phosphorylated glycogen synthase kinase-3β(GSK-3β) and glucose transporter 4(GLUT4). Our results suggest that PPPs possess of the beneficial effects on alleviating IR by enhancing insulin sensitivity and regulating glucose metabolism.

Preparation on Nanoemulsion of Pomegranate Peel Polyphenol

[Objective] The aim was to obtain the preparation technology of the pomegranate peel polyphenol nanoemulsion. [Method] The pomegranate peel polyphe- nol nanoemulsion was prepared by the titration methods and the pseudo ternary dia- gram. The effect of various elements on the formation of the nanoemulsion was stud- ied. [Results] The optimal prescription of the pomegranate peel polyphenol nanoemul- sion was 4.4%（w/w） of pomegranate peel polyphenol, 34.1%（w/w） of EL-40, 17.1%（w/w） of anhydrous ethanol, 5.7%（w/w） of IPM and 38.7%（w/w） of distilled water. [Conclusion] It is feasible to produce the pomegranate peel polyphenol nanoemulsion by the titration methods and the pseudo ternary diagram. It consists of pomegranate peel polyphe- nol, EL-40, anhydrous ethanol, IPM and distilled water. There is 4.4%（w/w） of the pomegranate peel polyphenol in the nanoemuJsion.

Effect of pomegranate peel polyphenol gel on cutaneous wound healing in alloxan-induced diabetic rats

Background Pomegranate （punica granatum） belongs to the family Punicaceae, and its peel has been used as a traditional Chinese medicine because of its efficacy in restraining intestine, promoting hemostasis, and killing parasites. Pomegranate peel has been reported to possess wound-healing properties which are mainly attributed to its polyphenol extracts. The purpose of this study was to investigate the effect of pomegranate peel polyphenols （PPP） gel on cutaneous wound healing in diabetic rats. Methods AIIoxan-induced diabetic rats were given incisional wounds on each side of the mid-back and then treated daily with PPP gel （polyphenol mass fraction =30%） post-wounding. Rats were sacrificed on days 4, 7, 14, and 21 post-wounding to assess the rates of wound closure, histological characteristics; and to detect the contents of hydroxyproline, production of nitric oxide （NO）, and activities of NO synthase （NOS）, as well as the expressions of transforming growth factor-β1 （TGF-β1）, vascular endothelial growth factor （VEGF）, and epidermal growth factor （EGF） in wound tissue. Results Wound closure was significantly shortened when PPP gel was applied to the wounds of diabetic rats. Histological examination showed the ability of PPP gel to increase fibroblast infiltration, collagen regeneration, vascularization, and epithelialization in the wound area of diabetic rats. In addition, PPP gel-treated diabetic rats showed increased contents of hydroxyproline, production of NO, and activities of NOS and increased expressions of TGF-β1, VEGF, and EGF in wound tissues. Conclusion PPP gel may be a beneficial method for treating wound disorders associated with diabetes.