Antidiabetic and Hypolipidemic Efficiency of Lactobacillus plantarum Fermented Oat (Avena sativa) Extract in Streptozotocin-Induced Diabetes in Rats

Abstract

Antidiabetic properties of fermented foods have been previously demonstrated. This study aimed to examine the antidiabetic and hypolipidemic potential activities of L. plantarum fermented oat extract in Streptozotocin-induced diabetic rats. Firstly, inoculating 1% of L. plantarum starter culture in 10% whole oat flour in aqueous media resulted in 8.36 log CFU mL−1 and pH 4.60 after 72 h of fermentation at 37 °C. With time progression of oat fermentation, total phenolic content (TPC), antioxidant activity (AOA), and γ-aminobutyric acid (GABA) contents were significantly increased up to 72 h. On the contrary, a significant reduction in β-glucan content was observed only after 72 h of fermentation. Secondly, separated aqueous extracts, i.e., unfermented oat extract (UFOE) and L. plantarum fermented oat extract (LFOE) were examined in vivo in a rat model, which consisted of five groups. Group 1 (negative group, NR); GROUP 2 (positive group, STZ), intraperitoneally injected with a single dose of 45 mg kg−1 BW of Streptozotocin and administered 7 mL of distilled water orally per day; Group 3 (STZ+MET), diabetic rats orally administered 50 mg of metformin kg−1 BW daily; Group 4 (STZ+UFOE), diabetic rats orally administered 7 mL of UFOE daily; and Group 5 (STZ+UFOE), diabetic rats orally administered 7 mL of LFOE daily for 6 weeks. Monitoring random blood glucose (RBG) and fasting blood glucose (FBG) showed that both the UFOE and the LFOE alleviated hyperglycemia in the STZ-induced diabetic rats. The extracts were significantly efficient in improving serum lipid profiles as compared with the positive group. Moreover, liver and kidneys’ functions were improved, and both extracts promoted hepatoprotective and nephroprotective characteristics. Furthermore, the administration of the UFOE and the LFOE efficiently attenuated GSH, CAT, and SOD enzymes and decreased MDA levels as compared with the positive group. In conclusion, data indicate the potential of UFOE and LFOE in future strategies as functional supplements against diabetes and diabetes-related complications.