Nobiletin is a polymethoxylated flavone, a type of natural compound found in plants. It is most abundantly found in the peels of citrus fruits, particularly tangerines, oranges, and lemons. As scientific research into its properties has grown, nobiletin has become more widely available as a dietary supplement.
Potential Health Benefits of Nobiletin
Nobiletin has attracted scientific interest for its diverse biological activities. However, much of the existing research is preliminary and has been conducted in laboratory settings or on animal models. Human clinical trials are still limited, and the findings do not constitute definitive health claims.
Metabolic Support
Research in animal models suggests nobiletin may influence metabolic processes. Studies on obese mice have indicated that nobiletin can play a role in managing body weight gain and improving insulin resistance. It has been observed to increase proteins and enzymes involved in energy and glucose metabolism. In hamsters with high cholesterol, certain citrus flavonoids have been shown to lower serum cholesterol by reducing VLDL and LDL concentrations.
Cognitive Function
In studies involving animal models of aging and neurodegenerative conditions, nobiletin has been shown to reduce memory and learning impairments. These effects are thought to be related to its ability to decrease the phosphorylation of tau, a protein that can form tangles in the brain associated with Alzheimer’s disease. Nobiletin has also been observed to increase the activity of antioxidant enzymes in the brain, which protect cells from damage.
Anti-Inflammatory Properties
Nobiletin demonstrates anti-inflammatory effects in laboratory studies. It has been shown to inhibit the activity of NF-κB, a protein complex that controls the expression of genes involved in inflammation. In cell cultures, nobiletin can decrease the production of nitric oxide and other pro-inflammatory molecules.
Natural Sources vs. Supplement Form
Obtaining nobiletin through diet involves citrus fruits, but the highest concentrations are located in the peel and pith. These parts are bitter and not consumed in significant quantities, making it difficult to ingest a substantial amount from food alone. The concentration in citrus peels can vary, with estimates ranging from 7 to 173 mg/kg of dry weight.
For this reason, supplements provide a concentrated and standardized dose that would be impractical to achieve by eating citrus peels, offering convenience and a consistent intake level.
Dosage and Administration
There is no official Recommended Dietary Allowance (RDA) or standardized dosage for nobiletin. The amounts available in commercial supplements can vary widely, and dosages used in scientific studies also differ. Animal studies have used various dosages, but these are not directly applicable to humans due to differences in metabolism and body weight.
Without established guidelines from robust human clinical trials, determining an appropriate dosage is challenging. Therefore, it is important for individuals to consult with a healthcare professional before taking a nobiletin supplement to discuss if it is suitable and what a potential starting dose might be.
Safety and Potential Side Effects
Nobiletin is considered to have low toxicity based on cellular and animal models, though potential side effects can include mild gastrointestinal upset. The primary safety consideration relates to its potential for drug interactions. Like other citrus flavonoids, nobiletin may interfere with enzymes that metabolize drugs, such as the cytochrome P450 3A4 (CYP3A4) enzyme system.
By inhibiting this enzyme, nobiletin could cause some medications to accumulate to unsafe levels in the bloodstream. Anyone taking medication should speak with their doctor or a pharmacist before using a nobiletin supplement to avoid potentially harmful interactions.