Enhancement and optimization of sinensetin extract from orthosiphon stamineus using supercrtitical carbon dioxide extraction

Abstract

Sinensetin is a rare valuable flavonoid compound that contains 5 methoxy groups attached on the flavone backbone. This compound is abundantly established in citrus peel and can also be found in medicinal herb, ‘misai kucing’. Scientifically, ‘misai kucing’ is known as Orthosiphon stamineus; mostly used to treat kidney stones by old folks. Orthosiphon stamineus was listed in National Key Economic Area (NKEA) as contributor towards the Malaysian Economic Growth. Thus, this study was conducted with objectives to determine suitable modifier for supercritical carbon dioxide (SC-CO2) extraction and to optimize the SC-CO2 extraction condition (pressure, temperature and average particle size) on the concentration of sinensetin. Water, methanol and acetone were used on the determination of modifier for SC-CO2 extraction by using water bath extraction at 40 °C in 8 hours. The results showed that acetone gave the highest percentage of sinensetin extract of 0.11%. Therefore, acetone was used as a modifier to enhance the extraction of sinensetin. The concentration of sinensetin was increased and the highest percentage of sinensetin obtained was 6.99%. Response surface methodology (RSM) through Box-Behnken design via Design Expert Software was applied to optimize the SC-CO2 conditions. The first-order polynomial was used to express the percentage of sinensetin with R2 value of 0.542. The optimum SC-CO2 operating condition was 30 MPa, 40 °C and 308.24 µm with sinensetin percentage of 4.35%. Hence, SC-CO2 with small amount of modifier was the best method to extract sinensetin as compared to water bath extraction method.