Anthocyanins are generally soluable in water and methanol.

Yes, but I'm wondering if there are any quantitate measurements of the solubility of any of the anthocyanins in any solvent. Thanks for the answer anyway.

I am not aware of such studies.

I found this one about Delphinidin J. Chem. Eng. Data 2010, 55, 2603–2606

The anthocyanins are generally soluble in water. But, the polyphenolic structure adds a measure of hydrophobic character which gives the anthocyanin solubility in organic solvents. The combination of this polar and hydrophobic nature makes aqueous/organic solvent mixtures the ideal solvent. Normally, the organic solvent content varies from 50% to 100% of the mixture. The organic solvent is usually methanol and ethanol but many other solvents have also been used such as acetone or acetonitrile.

I agree with Javier.

I add that the solvent choice depends on the final goal of your analysis: a buffer solution (pH 3.2) with ethanol 12 % is widely used (above all in Italy) to mimic what could happen in wines. I suggest to read the following pubblication: Lee and Rennaker, 2011, Influence of extraction methodology on grape composition values, Food Chemistry, 126:295-300.