Pterostilbene is a natural polyphenol compound produced by certain plants as a defense mechanism against pathogens. It is a structural analog of resveratrol, and its unique structure influences how it is absorbed and utilized by the body, differentiating it from other related polyphenols.
Natural Sources and Comparison to Resveratrol
Pterostilbene is found in small quantities in plant-based foods. Blueberries are the most well-known dietary source, containing amounts estimated to range from 99 to 520 nanograms per gram of fruit. It is also present in grapes and almonds. These natural sources provide modest levels of the compound compared to the concentrated doses found in dietary supplements.
Compared to resveratrol, pterostilbene has structural differences that impact its behavior in the body. Both molecules share a similar backbone, but pterostilbene possesses two methoxy groups where resveratrol has two hydroxyl groups. This alteration makes pterostilbene more fat-soluble, enhancing its ability to pass through cellular membranes.
This structural distinction is the reason for pterostilbene’s superior bioavailability, which is around 80% compared to 20% for resveratrol. The hydroxyl groups on resveratrol cause it to be metabolized and eliminated quickly, resulting in a short half-life of about 14 minutes. In contrast, pterostilbene’s methoxy groups make it more resistant to this breakdown, allowing it to remain in the body longer with a half-life of about 105 minutes.
How Pterostilbene Works in the Body
Pterostilbene’s biological actions are primarily antioxidant and anti-inflammatory. As an antioxidant, it counteracts oxidative stress by directly neutralizing reactive oxygen species (ROS), which are unstable molecules that can harm cells.
Pterostilbene also indirectly bolsters the body’s antioxidant defenses. It activates the Nrf2 signaling pathway, which acts as a master regulator of cellular antioxidant responses. This activation increases the production of protective enzymes like superoxide dismutase (SOD) and glutathione peroxidase.
The compound has anti-inflammatory effects by influencing cellular signaling pathways. It can inhibit the activation of nuclear factor-kappa B (NF-κB), a protein complex that controls the expression of genes involved in inflammation. By modulating this pathway, pterostilbene can reduce the production of pro-inflammatory molecules like TNF-α and various interleukins.
Another element of pterostilbene’s function is its ability to activate sirtuins, a class of proteins involved in cellular health and metabolism. Sirtuin-1 (SIRT1) is a particular target of pterostilbene. Activating SIRT1 is linked to cellular processes that support mitochondrial function and cellular resilience.
Current Research on Health Applications
Research into the health applications of pterostilbene is ongoing, with most studies being preclinical and conducted on animal models. One area of research is cognitive function. Rodent studies suggest pterostilbene may support memory and protect against age-related cognitive decline by reducing neuroinflammation and oxidative stress in the brain. Its ability to cross the blood-brain barrier makes it a compound of interest for neuroprotection, but human clinical trials are needed for confirmation.
Metabolic health is another focus of pterostilbene research. Animal studies have explored its effects on blood sugar and lipid metabolism, showing it may improve glucose homeostasis in some models. The compound is thought to exert these effects partly by activating PPAR-α, a protein that helps regulate the metabolism of fats and carbohydrates.
The compound’s influence on cellular aging is also being explored. Its antioxidant, anti-inflammatory, and sirtuin-activating properties are mechanisms that may help mitigate cellular stressors associated with aging. By protecting cells from damage and supporting mitochondrial function, pterostilbene is investigated for its potential to promote cellular longevity.
Safety and Bioavailability
Pterostilbene exhibits significantly higher bioavailability than resveratrol. Its chemical structure makes it more fat-soluble and less susceptible to rapid metabolic breakdown, allowing for greater absorption. This means a larger fraction of ingested pterostilbene can reach its target tissues compared to resveratrol.
Based on available human studies, pterostilbene appears well-tolerated at moderate dosages. Clinical trials have used doses ranging from 100 mg to 250 mg per day. In one study, doses up to 250 mg daily for 6-8 weeks did not result in significant adverse effects on liver or kidney function, and adverse events are reported as uncommon.
Some research points to a potential side effect related to cholesterol. One clinical trial found that pterostilbene alone led to an increase in low-density lipoprotein (LDL) cholesterol. This effect was reduced when pterostilbene was administered with grape extract, so individuals should be mindful of its potential impact on lipid profiles.