Luteolin is a naturally occurring compound belonging to a class of plant-based substances known as flavonoids, which contribute to the vibrant colors of many fruits and vegetables. First isolated in 1829, luteolin is a yellow crystalline solid. Chemically, it possesses a specific structure identified as a flavone, a subgroup of flavonoids, and this architecture is the foundation for its biological interactions.
Dietary Sources of Luteolin
Luteolin is present in a wide array of common vegetables and herbs, making it accessible through a balanced diet. Some of the most concentrated sources include:
- Celery, parsley, and green peppers
- Carrots, broccoli, cabbage, and onion leaves
- Apple skins
- Herbs like thyme, peppermint, rosemary, and oregano
Beyond solid foods, certain beverages also serve as sources of luteolin. Chamomile tea is a well-known provider, and the compound is also found in dandelion tea and olive oil. The concentration of luteolin in any plant can fluctuate based on factors like growing conditions, the part of the plant consumed, and how the food is prepared.
Biological Functions of Luteolin
Luteolin’s effects within the body are largely attributed to its antioxidant properties. Antioxidants work by neutralizing unstable molecules called free radicals. These molecules are byproducts of metabolic processes but can cause cellular damage if they accumulate. Luteolin’s chemical structure allows it to donate electrons to these free radicals, stabilizing them and preventing harm to DNA, proteins, and lipids within cells.
In addition to its antioxidant activity, luteolin exhibits anti-inflammatory functions. Inflammation is a natural immune response, but chronic inflammation can contribute to various health issues. Luteolin can inhibit certain enzymes that produce inflammatory compounds and interfere with signaling pathways like the nuclear factor kappa-B (NF-κB) pathway, which regulates the inflammatory response.
Research has also explored luteolin’s potential neuroprotective effects. By counteracting oxidative stress and inflammation in the nervous system, it may help support brain health by protecting neurons from damage. Luteolin also appears to have immune-modulating capabilities, meaning it can influence the activity and function of various immune cells.
Supplementation and Safety Considerations
Luteolin is available as a dietary supplement, often encapsulated alone or with other flavonoids, and is derived from plant sources. Dosages vary widely, ranging from 100 mg to 500 mg per serving. There is no established recommended daily intake (RDI) for luteolin, and optimal dosing has not been determined by regulatory agencies.
While luteolin from food is considered safe, high-dose supplements may cause side effects like stomach upset or headaches. There is also potential for interactions with certain medications. For example, due to its biological activities, luteolin could interact with anti-inflammatory drugs or other medications that affect the same cellular pathways.
Consulting with a healthcare professional is a necessary step before starting supplementation. A doctor or registered dietitian can help determine if a luteolin supplement is appropriate for an individual’s health circumstances and provide guidance on a suitable dosage.