Electrochemical Measurement of Antidiabetic Potential of Medicinal Plants Using Screen-printed Carbon Nanotubes Electrode

We developed cyclic voltammetry (CV)-based screen-printed carbon nanotubes (SP-CNTs) electrode system for the measurement antidiabetic potential of medicinal plants. The antidiabetic potential was measured by the ability of medicinal plant extracts to inhibit α-glucosidase (AG) enzyme that hydrolyses Pnitrophenol- α-D-glucopyranoside (PNPG) to release para-nitrophenol (p-NP). The SP-CNTs electrode system directly measured the released p-NP without any separation and purification steps. The bioactive phenolic compounds of the medicinal plant extracts are implicated to inhibit the enzymatic reaction. The antidiabetic potential of three different medicinal plants, namely, Tebengau (Ehretis laevis), Cemumar (Micromelum pubescens), Kedondong (Sponbias dulcis) and one commercial antidiabetic drug (Acarbose) were measured using the electrode system and excellent sensitivity was obtained (limit of detection 0.5 mg/mL). The results were verified using conventional UV-Vis spectroscopic system and excellent correlation was found (R2 = 0.982, 0.986, 0.976, 0.987 for Tebengau, Cemumar, Kedondong and Acarbose respectively), suggesting the reliability of the system among the three plants. Tebengau plant extracts exhibited the highest inhibition, indicating its potential application as a natural antidiabetic drug. The method is suitable for field level screening of antidiabetic potentials of herbs.