One-step, ultrasonication-mobilized, solvent-free extraction/synthesis of nanocurcumin from turmeric
Curcumin's current solvent-based extraction and poor solubility in water are two unresolved obstacles that limit the harnessing of this medicinal resource. To date, the extraction of curcumin from turmeric in water remains a challenge. This work resolves both these problems via a simple, ultrasonication-based, one-step strategy. Two different sonication methods, water bath type and probe sonication, were employed (using varying variables such as sonication time and sonication frequencies) to develop this one-step, water-based technique for extracting curcumin directly from turmeric. The probe sonication technique with sonication time within 5 min and 20 kHz frequency led to 55% curcumin extraction yield in water. This yield is even higher than that achieved by solvent-based extraction methods using ethanol. The ultrasonic physical conversion of micro-curcumin to nano-curcumin is shown to be the reason for the enhanced solubility of curcumin in water, leading to effective extraction. The results of this study suggest the use of probe ultrasonication for water-based extraction of curcumin from turmeric in a one-step process. This study also provides a solution for the bioavailability problem of curcumin, owing to its insolubility in water through nano-sizing of the curcumin using ultrasonication methods. The results and validation of these findings are reported in this communication.