Seasonal changes and solvent effects on fractionated functional food component yields from Mikania laevigata leaves.

Statistical mixture design extraction and fractionation of Mikania plant samples were carried out to quantitatively study seasonal and solvent composition effects as well as their interactions on secondary metabolites. The mixture design consisted of ethanol, acetone, dichloromethane and chloroform solvents and their binary, ternary and quaternary mixtures. Yields were measured for the crude extract and its neutral, organic, basic, polar and fiber fractions obtained with each solvent composition from samples harvested during 2010. Two-way ANOVA found statistically significant seasonal and solvent effects for the crude extract and all the fractions except for the polar fraction solvent. The best solvent extractor depends the harvest season. High crude, organic and polar fraction yields in the summer are correlated with the coumarin UV-vis absorbance at 274 nm. Crude yields of mixtures containing ethanol are correlated with the coumarin absorbances in summer, winter and spring whereas mixtures without ethanol show no significant correlation.