Purple Napiergrass (Pennisetum purpureum Schumach) Hot Water Extracts Ameliorate High-Fat Diet-Induced Obesity and Metabolic Disorders in Mice

Purple Pennisetum (Pennisetum purpureum Schumach), a hybrid between Taihucao No. 2 and the local wild species of purple Pennisetum, has dark red stems and leaves due to its anthocyanin content. This study explores the potential of purple napiergrass extracts (PNE) in alleviating obesity and metabolic disorders induced by a high-fat diet in mice, where 50% of the caloric content is derived from fat. Mice were orally administered low-dose or high-dose PNE alongside a high-fat diet. Experimental findings indicate that PNE attenuated weight gain, reduced liver, and adipose tissue weight, and lowered blood cholesterol, triglyceride, low-density lipoprotein, and blood sugar levels. Stained sections showed that PNE inhibited lipid accumulation and fat hypertrophy in the liver. Immunoblotting analysis suggested that PNE improved the inflammatory response associated with obesity, dyslipidemia, and hyperglycemia induced by a high-fat diet. Furthermore, PNE potentially functions as a PPAR-γ agonist, increasing the adiponectin (ADIPOQ) concentration and suppressing inflammatory factors, while elevating the anti-inflammatory factor interleukin-10 (IL-10) in the liver. PNE-treated mice showed enhanced activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) and AMP-activated protein kinase (AMPK) pathways and increased fatty acid oxidation and liver lipolysis. In conclusion, this study elucidated the mechanisms underlying the anti-inflammatory, PI3K/Akt, and AMPK pathways in a high-fat diet-induced obesity model. These findings highlight the potential of PNE in reducing weight, inhibiting inflammation, and improving blood sugar and lipid levels, showing the potential for addressing obesity-related metabolic disorders in humans.