Tag: Dimethylated resveratrol analog

Pterostilbene (trans-3,5-dimethoxy-4′-hydroxystilbene; CAS 537-42-8; molecular formula C16H16O3; molecular weight 256.30 g/mol) is a dimethylated analog of resveratrol first isolated from Pterocarpus marsupium heartwood in 1940 and subsequently identified in Vaccinium corymbosum (blueberry), Vaccinium ashei (rabbiteye blueberry), Vitis vinifera (grape), and several other plant species. The two methoxy groups at the 3- and 5-positions of the A-ring replace two of the three free hydroxyl groups present in resveratrol, conferring approximately fourfold greater lipophilicity, substantially reduced first-pass glucuronidation and sulfation, oral bioavailability of approximately 60 to 80 percent (compared to approximately 20 percent for resveratrol), a plasma elimination half-life of approximately 105 minutes (compared to approximately 14 minutes for resveratrol), and enhanced penetration across the blood-brain barrier. These pharmacokinetic advantages have positioned pterostilbene as a bioavailability-optimized stilbenoid for research into the pleiotropic pharmacology shared with the broader stilbene class. The molecular pharmacology of pterostilbene centers on four principal signaling axes. First, pterostilbene activates sirtuin 1 (SIRT1) and downstream PGC-1alpha deacetylation, promoting mitochondrial biogenesis, fatty acid oxidation, and cellular stress resistance. Second, it activates AMP-activated protein kinase (AMPK), suppressing hepatic gluconeogenesis, promoting glucose uptake, and enhancing lipid catabolism. Third, it activates the Nrf2/Keap1 antioxidant response element pathway by directly disrupting the Keap1-Nrf2 protein-protein interaction and by epigenetic derepression of the Nrf2 promoter, inducing downstream expression of heme oxygenase-1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), superoxide dismutase, and catalase. Fourth, it inhibits NF-kappaB and AP-1 transcriptional activity, attenuating pro-inflammatory mediator expression including inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor alpha, and interleukin-1 beta. Additional preclinical activity includes modulation of PI3K/Akt/mTOR signaling in oncology models, induction of apoptosis and autophagy in multiple cancer cell lines, and anti-angiogenic effects through suppression of vascular endothelial growth factor and matrix metalloproteinase-9. The clinical evidence base for pterostilbene in humans is modest but growing. The principal randomized controlled trial (Riche et al., 2014) evaluated pterostilbene at 50 mg and 125 mg twice daily for 6 to 8 weeks in 80 hypercholesterolemic adults and reported significant reductions in systolic blood pressure (7.8 mmHg, p < 0.01) and diastolic blood pressure (7.3 mmHg, p < 0.001) at 250 mg/day, with no adverse effects on hepatic, renal, or glucose markers. The same trial identified a significant increase in low-density lipoprotein cholesterol (17.1 mg/dL, p = 0.001) with pterostilbene monotherapy, an effect attenuated by concurrent grape extract administration. A second major clinical program evaluated the combination of nicotinamide riboside and pterostilbene (NRPT, marketed as Basis by Elysium Health) in a randomized, double-blind, placebo-controlled trial of 120 healthy adults aged 60 to 80, demonstrating dose-dependent increases in whole blood NAD+ of approximately 40 percent at the recommended dose and approximately 90 percent at double dose after four weeks (Dellinger et al., 2017). Subsequent NRPT trials have reported reduction of hepatic inflammation markers in nonalcoholic fatty liver disease and safety in acute kidney injury. Preclinical pharmacology is extensive. In rodent models, pterostilbene at doses of 10 to 100 mg/kg has demonstrated neuroprotection in Alzheimer's disease models (aluminum chloride-induced, streptozotocin-induced, amyloid-beta 25-35-induced), improvement in spatial and working memory, antidiabetic activity through AMPK-mediated suppression of hepatic gluconeogenesis, anticancer activity across breast, colon, prostate, lung, gastric, pancreatic, and oral cancer cell lines and xenograft models, and anti-inflammatory activity in models of colitis, myocardial ischemia, and acute lung injury. The compound crosses the blood-brain barrier and has been characterized as a more potent neuromodulator than resveratrol at equivalent doses in aging and Alzheimer's disease models (Chang et al., 2012). Pterostilbene is commercially available as a dietary supplement and as a research-grade chemical from multiple suppliers. It is not approved as a pharmaceutical in any jurisdiction. The compound is generally recognized as safe at doses up to 250 mg/day based on the available human safety data, with the LDL cholesterol elevation representing the principal metabolic safety signal requiring monitoring. This monograph reviews the chemistry, natural sources, and synthesis of pterostilbene; the multi-target molecular pharmacology; pharmacokinetics and metabolism; the preclinical evidence base across neuroprotection, oncology, metabolic disease, and inflammation; the human clinical evidence; sourcing and quality verification; reconstitution and handling; stack-interaction considerations; adverse events and safety signals; and a comparative assessment of five stilbenoid and polyphenol alternatives against pterostilbene on five competency standards.