This invention describes a simple, rapid and cost-effective method to isolate bulk quantities of relatively pure and enriched anthocyanidins and other plant bioactives. The method is based on the principle of solubility. Some bioactives (anthocyanidins) were extracted in an aqueous solvent, transferred to a non-aqueous solvent and finally insolubilized by adding a miscible solvent in which the bioactive was insoluble. Thus, anthocyanidins were isolated from anthocyanin-enriched berries or non-enriched, dark-colored fruits, vegetables and grains by extraction of anthocyanins, acid hydrolysis, and extraction of the resulting anthocyanidins, followed by their insolubilization (precipitation). Some bioactives (hydrophobic and hydrophilic) were extracted in a solvent with high solubility and then directly insolubilized by adding a miscible solvent in which the bioactive was insoluble, for example, withaferin A from enriched Withania somnifera and punicalagins from enriched punica extract.