Provided are processes for the preparation of compositions enriched in phenolic compounds from a crude plant extract. One process includes a novel column purification step using a polymer resin that releasably adsorbs the phenolic compounds but does not retain polar non-phenolic compounds, wherein the resin comprises aromatic rings substituted with one or more electron-withdrawing groups. This invention also includes compositions enriched in phenolic compounds. This invention encompasses methods of using the phenolic-enriched compositions for treating warm-blooded animals, including humans, infected with paramyxovaridae such as respiratory syncytial virus, orthomyoxovaridae such as influenza A, B, and C, parainfluenza, Herpes viruses such as HSV-1 and HSV-2, and Flaviviruses such as West Nile Virus, and for treating inflammation such as caused by arthritis, stress and digestive disease. The compositions are also useful as meat additives to inhibit food-borne pathogens.