A team of researchers at Chang Gung university in Taiwan say the best way to get an effective dose of the red wine compound resveratrol may not be through the mouth (to wine drinkers' chagrin) but rather through the skin. The scientists found that the most effective way to transmit resveratrol to the body is via a patch, according to experiments performed on mice.
Resveratrol is a potent phenolic compound found in the seeds and skins of grapes. Red wine is an abundant source of the chemical because of the extended contact between the juice and must during the winemaking process. More recently, the compound is being studied for its beneficial effects on the mitochondria of cells. Resveratrol also shows potential for treating and preventing various skin conditions, such as sunburns and melanoma.
The latter ability is what lured researchers at the Taiwanese university to conduct their study, the results of which were published in the May issue of the Biological & Pharmaceutical Bulletin. They confirm the skin benefits of resveratrol and cast doubt on the effectiveness of taking oral doses of the red wine compound.
Since the compound "is extensively metabolized in the body," researchers would have to up the amount given orally to mice into what would equal hundreds of bottles of wine per day for a human. Even if such high amounts were effectively compressed into a red wine-based pill, the study reports, the compound would be pricey as "this would require 2.7kg (5.95lbs) of resveratrol a year at a current cost of circa $6,800." Metabolism of the compound is slower on the skin, however, compared to the stomach, and the researchers observed that the half-life of resveratrol is longer and the chemical stronger when absorbed on the outside.
The scientists gathered a group of female nude mice—a mutant type of mice that have no fur. They prepared various types of skin patches with resveratrol, as well its derivative, piceatannol, a known anti-inflammatory, in order to test effectiveness. They also worked with various pH levels in order to find optimal "permeation" of the skin.
The scientists placed various oil- or glycerol-based solutions, dispensing either resveratrol or piceatannol, onto the skin of the mice and monitored the patches' ability to permeate for 12 hours. They found some promising results, but believe the best method is to use a resveratrol-based hydrogel patch, which uses water-based dispersion, at a pH of 8.0, which saw the highest concentration of the red wine chemical spreading onto the skin.
The scientists also noted that skin irritation with hydrogel patches is minimal and the patches tend to stick to the skin well, even in areas of high movement. They conclude that "delivery via a skin route may be a potent way to achieve the therapeutic benefits of resveratrol."
Lead author Jia-You Fang, a researcher at the university's pharmaceutical lab, said that this is just the beginning for resveratrol skin research. Future products, he added, may not be limited to patches, but could be extended to resveratrol-based sunscreens, for example.
According to Fang, the next stage involves more tinkering with the pH levels and amounts of resveratrol used on the hydrogels as "the different formulation for resveratrol largely affects the permeation into or across the skin," he said.
"Moreover, resveratrol retained within the skin after topical application can be an efficient way to be a therapy or prevention of UV exposure and skin carcinogenesis," the report read. "Further study is needed, of course, to confirm these efficiencies."