Hi guys,
I am seeing this rear it's ugly head lately around the web, so I am posting some items here for discussion regarding stability of resveratrol. In my opinion if res is protected from UV light and remains solid (such as a powder, or inside a powder capsule), it should be pretty stable. :
From a 1996 study:
Resveratrol: Isomeric Molar Absorptivities and Stability
-Brent C. Trela and Andrew L. Waterhouse
Resveratrol has attracted interest as a wine constituent that may reduce heart disease. Published
data on the molar absorptivity and chemical stability of cis- and trans-resveratrol have varied greatly.
Accurate values for UV absorbance for trans-resveratrol [UV ìmax (EtOH) nm () 308 (30 000)] and
cis-resveratrol [UV ìmax (EtOH) nm () 288 (12 600)] were determined and are used to improve
chromatographic quantitation methods. Trials conducted under a variety of commonly encountered
laboratory conditions show that trans-resveratrol is stable for months, except in high-pH buffers,
when protected from light. cis-Resveratrol was stable only near pH neutrality when completely
protected from light.
From a 2002 study regarding UV light:
"Capillary Electrophoresis Determination, Synthesis, and Stability of Resveratrol and Related 3-O-â-D-Glucopyranosides"
- VINCENZO BRANDOLINI,* ANNALISA MAIETTI,PAOLA TEDESCHI,ELISA DURINI, SILVIA VERTUANI, AND STEFANO MANFREDINI*
we have developed a specific protocol to identify and separate
resveratrol isomers and their corresponding glycosides, piceids,
from synthetic as well as natural sources. Furthermore, a study
on UV irradiation of trans-polydatin, aimed at obtaining the
corresponding cis isomer, has been also conducted, leading to
90% final conversion.
From a 2002 study regarding protection from light, while at room temperature:
An LC-MS Method for Analyzing Total Resveratrol in Grape Juice, Cranberry Juice, and in Wine
- YAN WANG,† FLORENTINA CATANA,† YANAN YANG,† ROBIN RODERICK,‡ AND RICHARD B. VAN BREEMEN*
The stability of resveratrol under different conditions was also examined. For
example, resveratrol was stable for up to 5 days at 4 °C in the dark but was not stable at room
temperature without protection from light. Resveratrol was detected in grape, cranberry, and wine
samples. Concentrations ranged from 1.56 to 1042 nmol/g in Concord grape products, and from
8.63 to 24.84 ímol/L in Italian red wine. The concentrations of resveratrol were silmilar in cranberry
and grape juice at 1.07 and 1.56 nmol/g, respectively."
From a 2006 study:
Resveratrol and Its Glycon Piceid Are Stable Polyphenols
- Jiri Prokop, Petr Abrman, Allen L. Seligson, and Milos Sovak
Solid trans-resveratrol and/or trans-piceid (resveratrol-3-
O-glucoside) were tested under accelerated stability condi-
ions for up to 4 years and under ambient conditions in a
mixture with other grape polyphenols for 2 years. As pre-
viously reported about resveratrol in grape pomace,
27 no significant decay in the content of resveratrol or piceid was ob-
served in the presence of atmospheric oxygen and humidity.
n addition, no by-products attributable to the stilbenoid
degradation, i.e., trans–cis isomerism or oxidation, were de-
ected.
Liquid resveratrol products may need better protection.
Cheers
A
