Kinetics, thermodynamics and antioxidant activities of water and ethanol extract of stem bark of Anacardium occidentale

Recently, extracts from various parts of A. occidentale had been massively investigated in the management and treatment of various ailments which include but not limited to diabetes, malaria, yellow fever as well as diarrhea. Stem bark of Anacardium occidentale was extracted with water and ethanol. Antioxidant activities of the extracts were using DPPH. For estimation of effective diffusivity, mathematical models which are based on basic fundamental laws of kinetics and mass transfer can be of immense importance. In this study, extraction kinetic data were subjected to pseudo first order and second order kinetic model. The kinetic of extraction in ethanol was best fitted with pseudo first order while that in water fitted best with the second order kinetic models. The isotherm fitted well with Power law models for ethanol and water extraction process. The transition rate theory was used to estimate the thermodynamic parameters which show that both processes are endothermic with values =H of 49.67 and 35.64 kJ mol-1 obtained for the ethanol and water extraction processes.