Coumarins and flavonoids are heterocyclic molecules that have been associated with beneficial effects on
human health, such as reducing the risk of cancer, diabetes, cardiovascular and brain diseases. These effects are thought to
be related to the radical scavenging effect, due to their antioxidant activities, along with other possible mechanisms, such
as anti-inflammatory properties and interaction with several enzymes. Over the past two decades, there have been an
increasing number of publications on coumarins and flavonoids, which demonstrate the importance of understanding the
chemistry behind the antioxidant activities of both natural and synthesized compounds, considering the benefits from their
dietary ingestion as well as pharmacological use. This work aims to review the antioxidant effects of coumarin and
flavonoid molecules in humans and the structural aspects that contribute to these effects.