Energy-efficient sonochemical extraction of bioactive compound karanjin from Pongamia pinnata leaves

The present study deals with the extraction of karanjin from Karanja leaves with the help of ultrasonic extraction. Karanjin is an important bioactive compound present in Karanja seed and leaves oil. The effect of various parameters such as solvents, temperature, time, ultrasonic power, duty cycle, stirring speed, and solute-to-solvent ratio on karanjin yield was investigated. The identification of extracted karanjin was assessed by high-performance liquid chromatography. The experimental results indicated that the extraction yield by ultrasound-assisted extraction (UAE) has increased by two times than the conventional (soxhlet) method. It is also found that for achieving the same amount of yield, soxhlet required 24 h, while UAE takes only 30 min. The yield of karanjin increased with the solute-to-solvent ratio, whereas an increase in temperature leads to a reduction in karanjin yield. Particle size distribution and scanning electron microscope images of the plant cells after UAE treatment indicate microfractures on the plant cell's surface by the cavitation phenomenon. It also gives the visuals confirmation of the sonication effect. During the sonication, 12.03 kJ/g of energy was delivered, while 48 kJ/g of energy is required for the soxhlet method. Karanjin can be a promising biopesticide or bioinsecticide material in a wide range of applications. Thus, the developed UAE method provides a better process intensification approach to extract karanjin and makes it an exciting alternative for downstream processing. [GRAPHICS] .