Anti-diabetic and gut microbiota modulation effects of sacha inchi (Plukenetia volubilis L.) leaf extract in streptozotocin-induced type 1 diabetic mice

Abstract

<h3>BACKGROUND</h3><p>Sacha inchi (<em>Plukenetia volubilis</em> L.) tea has been used as an adjuvant treatment for diabetes in Pu’er, in the Yunnan province of China. The effects of sacha inchi tea on diabetes and the underlying mechanisms remain unknown. This study was conducted to investigate the influence of a water extract of sacha inchi (<em>P. volubilis</em> L.) leaves (PWE) on hypoglycemic activity and gut microbiota composition in mice with streptozotocin (STZ)-induced type 1 diabetes mellitus (T1DM). During the 6 weeks of the study, T1DM mice were administered PWE intragastrically at 400 mg kg⁻¹ body weight (BW) per day.</p><h3>RESULTS</h3><p>Treatment with PWE reduced excessive loss of BW and excessive intake of food. It significantly decreased blood glucose levels and improved oral glucose tolerance. The treatment caused protective histopathological transformations in sections of the pancreas, leading to decreased insulin resistance and improved insulin sensitivity. Treatment with PWE also significantly ameliorated disorders of the gut microbiota structure and increased the richness and diversity of intestinal microbial species in T1DM mice. At the genus level, the populations of several crucial bacteria, such as <em>Akkermansia</em>, <em>Parabacteroides</em>, and <em>Muribaculum</em> increased in the PWE treatment group but the abundance of <em>Ruminiclostridium</em> and <em>Oscillibacter</em> decreased.</p><h3>CONCLUSIONS</h3><p>Treatment with PWE can ameliorate hyperglycemic symptoms in STZ-induced T1DM mice, and the anti-diabetic effect of PWE was related to the amelioration of gut microbial structural disorder and the enrichment of functional bacteria.</p>