Extraction of Anthocyanin-Rich Extract From Lonicera caerulea and Its Hypoglycemic Activity

Anthocyanins, as water-soluble natural pigments, have garnered increasing interest in the field of natural products due to their significant biological activities. While existing studies have verified the hypoglycemic potential of Lonicera caerulea anthocyanins, few investigations simultaneously cover in vitro enzyme activity, in vivo hypoglycemic efficacy and the underlying regulatory mechanisms relevant to Type 2 diabetes. This research investigates the extraction conditions, and hypoglycemic effects in vitro and in vivo of L. caerulea anthocyanin-rich extract (LCAE). The extract was prepared using ultrasound-assisted acidified ethanol extraction followed by purification with macroporous adsorption resin. The maximum yield and purity of anthocyanin were 2.90 ± 0.06 mg/g and 22.10%, respectively. In vitro, LCAE effectively scavenged DPPH, ABTS˙⁺, and ˙OH radicals in a concentration-dependent manner, while also inhibiting α-glucosidase activity with a maximum inhibition of 82.79%. In vivo, a C57BL/6J mouse model of Type 2 diabetes mellitus (T2DM) was established using a high-fat diet (HFD) combined with streptozotocin (STZ). LCAE significantly reduced fasting blood glucose (FBG) and glycated serum protein (GSP) levels. LCAE also improved the area under the curve (AUC) in the oral glucose tolerance test (OGTT), lowered HOMA-IR, and enhanced insulin sensitivity, as evidenced by the quantitative insulin sensitivity check index (QUICKI). In addition, LCAE reduced serum levels of pro-inflammatory cytokines (IL-1β, TNF-α, IL-6), increased IL-10, enhanced hepatic antioxidant enzyme activities (CAT, SOD, GSH-PX), and decreased MDA levels. Furthermore, LCAE ameliorated dyslipidemia in the liver and serum, alleviated hepatic steatosis, and pancreatic islet injury, downregulated hepatic PEPCK, G6Pase, Pcx gene expression, and upregulated AMPK expression. Overall, LCAE alleviated metabolic dysregulation in T2DM mice via multi-target synergistic actions, providing experimental evidence for the potential development of LCAE as a natural functional hypoglycemic agent. PRACTICAL APPLICATIONS: Blue honeysuckle (Lonicera caerulea L.) is a plant with both medicinal and food uses. Rich in bioactive compounds such as anthocyanins, it exhibits various biological activities, including antioxidant and hypoglycemic effects. Anthocyanin-rich extracts derived from blue honeysuckle show promise as a natural ingredient for use in functional beverages or dietary supplements designed to help manage Type 2 diabetes.