Statistical mixture design - Principal component determination of synergic solvent interactions for natural product extractions

Ethanol, ethyl acetate, dichloromethane, acetone and chloroform mixtures of a simplex centroid design have been used to extract total crude material as well as the neutral, organic, basic, fiber and residue fractions of Mikania laevigata Sch. Bip. leaves. The quantity of crude extracted material is found to depend on the solvent proportions according to a special cubic model. Synergic binary solvent effects between the ethanol-ethyl acetate, ethanol-dichloromethane, ethanol-chloroform, ethyl acetate-chloroform and ethyl acetate-dichloromethane pairs are found to explain the superior extraction results of the mixtures compared to results for the pure solvents. These significant synergic binary effects are seen to occur between solvents having disparate acidity, basicity and/or dipolarity parameters located at extremities of the domain defined by the mixtures within the Snyder-Rohrschneider solvent selectivity triangle. So molecular interactions known to be important for chromatographic separations are also significant for separating crude material from its Mikania laevigata Sch. Bip. leave matrix. Principal component analysis shows these interaction effects to be important for obtaining higher yields of the fractionated materials. (C) 2010 Elsevier B.V. All rights reserved.