Alpha-Glucosidase Enzyme Biosensor for the Electrochemical Measurement of Antidiabetic Potential of Medicinal Plants

Abstract

A biosensor for measuring the antidiabetic potential of medicinal plants was developed by covalent immobilization of α-glucosidase (AG) enzyme onto amine-functionalized multi-walled carbon nanotubes (MWCNTs-NH2). The immobilized enzyme was entrapped in freeze-thawed polyvinyl alcohol (PVA) together with p-nitrophenyl-α-d-glucopyranoside (PNPG) on the screen-printed carbon electrode at low pH to prevent the premature reaction between PNPG and AG enzyme. The enzymatic reaction within the biosensor is inhibited by bioactive compounds in the medicinal plant extracts. The capability of medicinal plants to inhibit the AG enzyme on the electrode correlates to the potential of the medicinal plants to inhibit the production of glucose from the carbohydrate in the human body. Thus, the inhibition indicates the antidiabetic potential of the medicinal plants. The performance of the biosensor was evaluated to measure the antidiabetic potential of three medicinal plants such as Tebengau (Ehretis laevis), Cemumar (Micromelum pubescens), and Kedondong (Spondias dulcis) and acarbose (commercial antidiabetic drug) via cyclic voltammetry, amperometry, and spectrophotometry. The cyclic voltammetry (CV) response for the inhibition of the AG enzyme activity by Tebengau plant extracts showed a linear relation in the range from 0.423–8.29 μA, and the inhibition detection limit was 0.253 μA. The biosensor exhibited good sensitivity (0.422 μA/mg Tebengau plant extracts) and rapid response (22 s). The biosensor retains approximately 82.16 % of its initial activity even after 30 days of storage at 4 °C.

A General Overview of Support Materials for Enzyme Immobilization: Characteristics, Properties, Practical Utility

“…In another study α-glucosidase was covalently immobilized on multi-walled carbon nanotubes functionalized by amine groups. The system so obtained was used in a biosensor for measuring the antidiabetic potential of medicinal plants [120]. The immobilized enzymes used in both biosensors exhibited greatly improved sensitivity and time of response and thus better detecting properties.…”

Production and biochemical characterization of α-glucosidase from Aspergillus niger ITV-01 isolated from sugar cane bagasse

“…Some α-glucosidases have transglucosylase activity and produce isomalto-and malto-oligosaccharides (IMOs) such as isomaltose, maltotriose, panose and nigerose (Duan et al 1994;Kato et al 2002). Therefore, α-glucosidases could be used to produce IMOs with prebiotic activity (Chiba 1997;Chen et al 2010), glucose from starchy sources in industrial brewing, also for syrup and biofuel production and recently in medical biosensors (Mohiuddin et al 2016).…”

Recent Advances in Electrochemical Biosensors Based on Enzyme Inhibition for Clinical and Pharmaceutical Applications

“…Furthermore, α-glycosidase enzyme was immobilized onto an amine-functionalized multiwalled carbon nanotubes (MWCNTs-NH 2 )-based electrode [ 128 ]. The biosensor was applied in the screening of potential inhibitors from medicinal plant extracts that have an anti-diabetic action.…”