There’s enough research showing that grapes have anti-inflammatory properties and antioxidants. Resveratrol antioxidant is found on the skin of grapes. This compound is helpful when it comes to treating arthritis. In addition, resveratrol antioxidant prevents the formation of arthritis cells, thus reducing the rate of joint thickening associated with rheumatoid arthritis. Grapes also contain proanthocyanidin compounds that have shown promising results in treating arthritis.