Efficient Solvent Selection Approach for High Solubility of Active Phytochemicals: Application for the Extraction of an Antimalarial Compound from Medicinal Plants

The proposed approach unveils an efficient solvent selection manner for the extraction of active compounds from medicinal plants based on their high solvency for the target compound while considering green engineering principles. Rationalization of resources is achieved through theoretical screening using the Hansen solubility parameters in practice (HSPiP) approach of 26 solvent candidates toward the solvency of the antimalarial drug artemisinin. Solvent selection is challenged to meet some green engineering principles, from which four solvents are identified and then confirmed using gravimetric tests. The highest solubility at 20 degrees C is attributed to dimethyl sulfoxide with 103.7 mg.mL(-1), while isopropanol recorded 8.45 mg.mL(-1). Despite being a polar solvent, propylene glycol gave a very low solubility of 0.6 mg.mL(-1). Being a food grade with very low global warming potential score, isopropanol stands as a green alternative to substitute n-hexane, where solubility measurements using changes of turbidity measurement indicate good solvency for artemisinin with 39.92 mg.mL(-1) at 40 degrees C, a temperature at which generally extraction is conducted. Application of isopropanol to artemisinin extraction from Artemesia annua L. indicates a good artemisinin yield of 65% in only a single batch sequence at which the recovered crystals have a purity of more than 67%.