What is Resveratrol?

Resveratrol is a type of phytoalexin produced by plants in response to external influences such as mechanical damage, ultraviolet (UV) exposure, and fungal attack. Resveratrol is the cornerstone molecule of a family that includes glycosides (piceid) and polymers (viniferins). Its fundamental structure features two aromatic rings connected by a methylene bridge, existing in both cis and trans isoforms. These structures have the capacity to attach to glucose, resulting in the formation of cis/trans-piceid. The cis/trans-piceid is a stilbene glycoside compound that releases resveratrol by the action of glycosidase in the gut. It has similar pharmacological effects as resveratrol and can be converted into each other in the body.

Source of Resveratrol

Resveratrol was first partially isolated from the bulb of Veratrum album in 1939 and later from the root of Polygonum cuspidatum in 1963. Later, the French discovered that wine also contained Resveratrol. Grapes and wine are the most common dietary sources of resveratrol, and the content is often related to variety, origin, ripeness, brewing method, and grape fermentation time. In general, the resveratrol content of red wine is higher than that of white wine. Other primary dietary sources of resveratrol include peanuts, mulberries, blueberries, and strawberries. The levels of Resveratrol in food are shown in Table 1.

Pharmacological Actions of Resveratrol

Resveratrol is a natural phenolic compound with a wide range of pharmacological effects including: antioxidant, anti-inflammatory, antimicrobial, anti-angiogenic, anticancer, immunomodulatory, neuro- and cardioprotective, anti-dyslipidaemic and anti-diabetic. As such, Resveratrol has many potential health benefits for the prevention and treatment of various chronic diseases.

Studies have shown the health benefits of consuming 30-150 mg of resveratrol per day, but it is difficult to achieve the required starting dose in our daily diet. Therefore, the body needs additional resveratrol supplements in order to achieve optimal body functioning.

A randomised double-blind crossover study was done to verify, for the first time, the metabolic effect of resveratrol in obese men. Twenty-two obese subjects, otherwise in good health, mean age 52 years, were randomised in two groups receiving placebo or 150 mg/day resveratrol for 4 weeks. Resveratrol significantly decreased sleeping and resting metabolic rate.

In muscle, the treatment with resveratrol activated AMPK, increased the levels of SIRT1 and PGC-1α proteins, increased the activity of citrate synthase without change in mitochondrial content, and improved the mitochondrial respiration when a lipid substrate was used. Lipid levels were increased in muscle cells and decreased in the liver in subjects receiving resveratrol. The treatment with resveratrol also decreased circulating glucose, triglycerides, alanine-aminotransferase and inflammation markers. Resveratrol significantly lowered systolic blood pressure and improved HOMA index, suggesting positive effects on insulin sensitivity. Adipose tissue lipolysis and plasma fatty acid and glycerol decreased during the postprandial period.

Trans-resveratrol has an established acceptable daily intake (ADI) of 450 mg/day. The ADI is based on a 13-week study that used a no-observed-adverse-effect-level (NOAEL) of 750 mg/kg/day. If more than one gram of trans-resveratrol is taken, it may cause gastrointestinal discomfort, such as diarrhea and nausea, usually within an hour of consumption

References:

[1] MENNINI T. Resveratrol supplementation[J]. Nutrafoods, 2012. DOI:10.1007/S13749-012-0016-0.

[2] XU Y, FANG M, LI X, et al. Contributions of Common Foods to Resveratrol Intake in the Chinese Diet[J]. Foods, 2024. DOI:10.3390/foods13081267.