Resveratrol Isomers Found in OTC Capsules

Two isomers of Resveratrol were observed using this simple Reversed Phase Method. Different capsules were analyzed and it was discovered that some had both isomers while the cis isomer was not detected in others (data not shown).

The ability of this Method to Separate two Isomers is a good example of determining capsule to capsule consistency. In the figure below, data from two column lots are shown to illustrate the Method Robustness and Reproducibility.

1. trans-Resveratrol
2. cis-Resveratrol

Method Conditions
Column: Cogent Bidentate C18™, 4μm, 100Å
Catalog No.: 40018-75P
Dimensions: 4.6 x 75mm
Mobile Phase:
A: DI Water with 0.1% Formic Acid
B: Acetonitrile with 0.1% Formic Acid

Time (minutes) %B
0 10
1 10
9 40
10 10

Post Time: 3 minutes
Injection vol.: 1μL
Flow rate: 1.0mL / minute
Detection: UV @ 308nm
Sample Preparation: 100mg strength Resveratrol Capsule contents were added to a 100mL volumetric flask containing a portion of 50:50 Solvent A / Solvent B diluent. It was then sonicated 10 minutes and diluted to mark. After mixing, a portion was filtered with a 0.45μm Nylon Syringe Filter (MicroSolv Tech Corp.).
t0: 0.9 minutes

Note: Resveratrol is a natural product found in the skin of red grapes and other sources. Still unproven, it has been reported to have anticancer, anti-aging, cardio-protective, and anti-diabetic effects.


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