4:1 Extract Targeted Wellness Potency – Purity – Pride Antioxidant Support Herbal Supplement Superior quality, concentrated (4:1) grapefruit seed extract. What are the key benefits of Vitacost® Grapefruit Seed Extract? Grapefruit seed extract contains naturally occurring citrus bioflavonoids Bioflavonoids are primarily noted for their powerful antioxidant properties in addition to their many diverse biological activities. Research shows a positive effect of bioflavonoids from citrus fruits such as grapefruit and a correlation to a healthy inflammatory response.