Optimizing ultrasound-assisted extraction for enhanced quantification of 7-hydroxymitragynine and mitragynine in kratom

This study focuses on optimizing the extraction of two key alkaloids, mitragynine and 7-hydroxy mitragynine, from kratom (Mitragyna speciosa) leaves using ultrasound-assisted extraction (UAE). The aim was to identify optimal extraction conditions by varying sample-to-liquid ratio, solvent types, methanol concentrations, ultrasonic power, and extraction time. High-performance liquid chromatography with diode array detection (HPLC-DAD) was used to quantify the alkaloids accurately. The results indicate that using a sample-to-liquid ratio of 0.5:10 g mL-1, 70% v/v methanol as the solvent, with an ultrasonic power of 175 watts, and a 10 min for extraction time, yielded the highest amounts of mitragynine and 7-hydroxymitragynine. This method offers a reliable, efficient approach for extracting and quantifying these bioactive compounds, supporting the development of standardized kratom products for quality control. The study has practical applications for local farmers in Phetchabun province, improving the extraction process for kratom leaves. GRAPHICAL ABSTRACT HIGHLIGHTS Ultrasound-assisted extraction (UAE): the study focuses on optimizing the use of UAE for the efficient extraction of two key alkaloids, mitragynine and 7-hydroxymitragynine, from kratom leaves. Optimal extraction conditions: the research identifies the best conditions for UAE, including solvent type, methanol concentration, ultrasonic power, and extraction time, to maximize the yield of the target compounds. Quantitative analysis: high-performance liquid chromatography (HPLC-DAD) was used for precise quantification, providing a reliable method for analyzing these alkaloids in kratom samples sourced from local farmers.