Antidiabetic Effects of Coffee Silverskin Extract in Streptozotocin-Induced Diabetic Wistar Rats

Diabetes mellitus (DM) is a major health problem that has reached alarming levels. The valorization of food wastes has become a priority research line in order to achieve a sustainable food industry. Coffee industry generate large amounts of by-products that are rich in bioactive phytochemicals. Coffee Silverskin (CS) is a thin tegument of the outer layer of the coffee bean and is the only by-product of the roasting process. This research was aimed to explore the diabetes-healing effects of CS extract (CSE). Before secondary screening on animals, phytochemical constituent identification, and antioxidant activity were performed. Then, streptozotocin-induced hyperglycemia in Wistar albino rats was carried out. Regular observations and different metabolic parameters were assessed. In vitro results showed that CSE was rich in polyphenols and flavonoids. Current characteristics of CSE include many principal secondary metabolites on HPLC, mainly caffeine and chlorogenic acid. CSE possesses also a significant antioxidant activity. Regarding the in vivo activities, CSE shows promising efficacy in reducing blood glucose level, glycated hemoglobin, total cholesterol, low-density lipoprotein, and hepato-renal biomarkers, and success in elevating body weight, high-density lipoprotein, and insulin levels. The histopathological reports showed significant improvements against liver and kidney damages. Analysis of the obtained data indicates the effect of CSE in improving the complications of diabetes. The overall antidiabetic activity of CSE can be traced to its phytochemical constituents and antioxidant activity. CSE could be a promising antidiabetic agent, thereby enhancing the high added value of this coffee by-product.