Researchers attribute sour cherry juice's ability to combat the symptoms of arthritis to the anthocyanin compounds it contains, according to the Arthritis Foundation. Red and purple fruits, especially tart cherries, contain an abundance of anthocyanin compounds and have powerful anti-inflammatory and antioxidant properties. Blueberries and raspberries also contain anthocyanin compounds.
Although research into cherry juice is ongoing, as of 2015, one study found that participants consuming two 8-ounce bottles of juice each day for six weeks saw a reduction in pain and stiffness caused by osteoarthritis and a reduction in the inflammation markers associated with the condition, reports the Arthritis Foundation. Researchers obtained similar results with cherry supplements containing anthocyanin compounds.