Phenolic profiles, antihyperglycemic, antihyperlipidemic, and antioxidant properties of pomegranate (Punica granatum) peel extract

This work is aimed to evaluate phenolics composition, and in vitro antioxidant activities of hydro-methanol pomegranate (Punica granatum L.) peel extract (MPE). In addition, the antihyperglycemic, hypolipidemic, and hepatoprotective effect of MPE in Wister albino rats was compared with standard drugs (glibenclamide and atorvastatin). Total phenolic content and total flavonoid contents in MPE (mg g(-1)) accounted for 188.9 as GAE and 13.95 as QE, respectively. Phenolic and flavonoids compounds in MPE analyzed by HPLC and revealed the presence of 23 phenolic compounds and 20 flavonoid compounds. For in vivo experiment, 56 rats were distributed into 8 groups. Group 1 was the normal control, while group 2 contained rats orally administrated with 200 mg kg(-1) MPE daily. Group 3 contained diabetic rats (induced with a single dose of 100 mg/kg b.w. alloxan). Group 4 contained diabetic rats administered daily with 200 mg/kg MPE. Group 5 contained diabetic rats administered orally with a glibenclamide (standard drug for diabetic) at 10 mg/kg daily. Group 6 fed with high fat diet (HFD). Group 7 contained HFD-rats administered orally with 200 mg/kg MPE daily. Group 8 contained HFD-rats administered orally with atorvastatin (used to lower LDL-cholesterol (LDL-C) and fats and to raise HDL-cholesterol (HDL-C) in the blood) at 10 mg/kg daily. The study lasted for 56 days. Administration with MPE 200 mg/kg to both diabetic and hyperlipidemic rats significantly decreased blood glucose, HbA(1c), total lipid, total cholesterol, LDL-C, and very low density lipoprotein cholesterol levels, while increased high density lipoprotein cholesterol levels, as well as improved liver and kidney functions, compared with glibenclamide and atorvastatin effects. Practical applications Pomegranate peel, constituted about 50% of fruit fresh weight, is rich in bioactive compounds with potent health-promoting activities. The results of the current study stated that MPE is rich in phenolics and flavonoids with powerful antioxidant potential. In addition, MPE showed antihyperglycemic and antihyperlipidemic activities due to the strong antiradical action via its antioxidant compounds. MPE enhanced liver and kidney functions when compared to standard drugs in diabetic and hyperlipidemic rats. MPC could be used as a natural material to develop diabetic and hyperlipidemic drugs.