SX-fraction: Promise for novel treatment of type 2 diabetes

Abstract

SX-fraction (SXF) is a bioactive glycoprotein with anti-diabetic and hypoglycemic activities that have been documented in several reports. We have reviewed those studies herein and also explored the possible mechanism of its hypoglycemic activity. The early animal studies of SXF using diabetic mice showed the significant reduction in the three diabetic parameters, serum glucose, insulin, and triglyceride, suggesting its anti-diabetic activity. The limited clinical studies also showed that SXF led to the significant reduction in the fasting blood glucose levels of type 2 diabetic patients within 2 wk or a month, suggesting its hypoglycemic activity. To explore the hypoglycemic mechanism of SXF, its possible effects on the insulin signal transduction pathway was examined in vitro. Particularly, activities of insulin receptor, insulin receptor substrate 1, and protein kinase B, which are essential elements playing a key regulatory role in the signal pathway, were studied using skeletal muscle L6 cells. The status of these three parameters were examined under a high glucose (35 mmol/L) milieu with SXF and assessed using the enzyme-linked immunosorbent assay. Such studies revealed that all three parameters (insulin receptor, insulin receptor substrate 1, and protein kinase B) were inactivated by high glucose, indicating a disruption of the signal pathway. However, such an inactivation was reversed or re-activated by SXF to successfully carry out the sequential signaling events. In fact, a measurement of glucose uptake in cells showed that SXF did increase a glucose uptake while high glucose decreased it. Therefore, SXF has anti-diabetic and hypoglycemic activities through activation of the insulin signal pathway and appears to be a safe, natural agent for lowering the serum glucose levels in type 2 diabetic patents and improving their diabetic conditions.

Keywords: SX-fraction; Diabetes; Anti-diabetic; Hypoglycemic; Insulin signal pathway

Core Tip: We have been searching for a natural agent capable of controlling diabetic conditions in patients with type 2 diabetes for years. We then came across “SX-fraction (SXF)”, isolated from maitake mushroom (Grifola frondorsa), with anti-diabetic and hypoglycemic activities. In this short review, we chronologically described several key studies of SXF such as animal studies using diabetic mice (to demonstrate anti-diabetic activity), limited clinical studies on volunteer patients with type 2 diabetes (to show hypoglycemic activity), and in vitro study using skeletal muscle cells (to elucidate the hypoglycemic mechanism). After all, SXF appears to be a natural, safe, effective agent for treatment of patients with type 2 diabetes, although more (clinical) studies are yet required for confirmation.