ELECTROCHEMICAL STUDY OF ALOE GEL AND EMODIN ON A SCREEN PRINTED CARBON ELECTRODE

Abstract

The most useful part of natural aloe vera is aloe-gel (AG) and aloe-emodin(AE). AE has various
pharmacological effects including, antiviral, antimicrobial and laxative activities, while AG has mainly been
used as an anti- inflammable agent. Some medical activities are related to their redox activity. This paper
presents a simple strategy to carry out of AG and AE based on screen printed carbon electrode (SPCE). The
electrochemistry of AG and AE was investigated at pH 7.05 by cyclic voltammetry and differential pulse
voltammetry. The redox mechanism is discussed. Results showed that the available working potential range
for the study was the potential window between 0.60 V to -0.40 V and the peak currents of the cathodic peak
increased linearly with the square root of scan rate. The peak potentials of the cathodic peaks shifted negatively
as pH increased from 3.05 to 9.07. The appearance of other cathodic and anodic peak in fresh aloe vera sample
indicates that the fresh aloe vera consists of several redox active species. It is concluded that a low cost, easy
and convenient detection of aloe emodin was successfully achieved with this electrochemical system.