Isolation and characterization of an α-glucosidase inhibitor from Musa spp. (Baxijiao) flowers.

Zhanwu Sheng,Haofu Dai,Weihong Ma,Yingying Hu,Siyi Pan,Hui Wang

doi:10.3390/molecules190710563

Abstract

The use of α-glucosidase inhibitors is considered to be an effective strategy in the treatment of diabetes. Using a bioassay-guided fractionation technique, five Bacillus stearothermophilus α-glucosidase inhibitors were isolated from the flowers of Musa spp. (Baxijiao). Using NMR spectroscopy analysis they were identified as vanillic acid (1), ferulic acid (2), β-sitosterol (3), daucosterol (4) and 9-(4′-hydroxyphenyl)-2-methoxyphenalen-1-one (5). The half maximal inhibitory concentration (IC50) values of compounds 1–5 were 2004.58, 1258.35, 283.67, 247.35 and 3.86 mg/L, respectively. Compared to a known α-glucosidase inhibitor (acarbose, IC50 = 999.31 mg/L), compounds 3, 4 and 5 showed a strong α-glucosidase inhibitory effect. A Lineweaver-Burk plot indicated that compound 5 is a mixed-competitive inhibitor, while compounds 3 and 4 are competitive inhibitors. The inhibition constants (Ki) of compounds 3, 4 and 5 were 20.09, 2.34 and 4.40 mg/L, respectively. Taken together, these data show that the compounds 3, 4 and 5 are potent α-glucosidase inhibitors.

Highlights

Diabetes mellitus has become an alarming global problem in recent years
This enzyme is ubiquitous in plants, microorganisms, and animal tissues, the substrate specificity of α-glucosidase differs greatly depending on the source [2]. α-Glucosidase inhibitors can decrease the postprandial increase in blood glucose and in turn help avoid the onset of late diabetic complications [3]
The crude extract was evaporated under vacuum, and the concentrated extracted was dispersed in water and partitioned successively with petroleum ether, ethyl acetate and n-butanol to obtain the PEF, EAF, BUF

Summary

Introduction

Diabetes mellitus has become an alarming global problem in recent years. Postprandial hyperglycemia plays an important role in the development of diabetes mellitus type II and the resulting complications. Α-Glucosidase (EC 3.2.1.20) is a glucosidase that acts on 1,4-α bonds, breaking down starch and disaccharides into glucose This enzyme is ubiquitous in plants, microorganisms, and animal tissues, the substrate specificity of α-glucosidase differs greatly depending on the source [2]. Α-Glucosidase inhibitors can decrease the postprandial increase in blood glucose and in turn help avoid the onset of late diabetic complications [3] From this perspective, researchers have focused on finding more effective α-glucosidase inhibitors from natural materials for use as antidiabetic compounds, such as triterpene glycoside from Acanthopanax senticosus Harm leaves [4], flavonoid glycosides in Microctis folium [5] and polyphenols from green tea [6]. Many banana flowers are produced; to date, in China they have only been used as organic material and fertilizer in the plantations

Objectives

Results

Conclusion