Removal of fluoride using quaternized palm kernel shell as adsorbents: equilibrium isotherms and kinetics studies

Abstract

Andrographis paniculata is widely used by local people from Southeast Asia countries for traditional medication. Recently, the demand for this herb and its extract is in the increasing trend, particularly for herbal related product development. Therefore, this study investigated the optimization of A. paniculata extraction in a reflux system, and the fractionation of the plant crude extract for andrographolide enriched extract using column chromatography. The extraction variables such as the ratio of plant leaves to solvent (1:9), extraction temperature (73 °C) and time (1.9 h) were optimized by the desirability, 0.85 based on the three levels and three factors of Box-Behnken design. The yield of extraction (17.2% w/w) and the concentration of andrographolide (140.5 ppm) were the responses for the optimization using a quadratic model in the response surface methodology. A pattern recognition tool of principle component analysis was used to determine the similarity of the andrographolide enriched extracts, in term of their chemical composition produced from the column chromatography at different ethanol concentrations (20-100%) as eluent. The first principle component explained for >40% of the total variance, which explained the high similarity of chemical composition in the extracts. The eluent system of 40% ethanol was chosen for andrographolide fractionation as it required the lowest volume of eluent (950 mL) for high concentration of andrographolide production (1.9% w/w). The combination of reflux extraction with column chromatography was successfully used for the preparation of andrographolide enriched extract.