Analysis of Resveratrol
Resveratrol is a type of polyphenol that has been attracting attention as a natural antioxidant. Although all polyphenols have antioxidant effects, resveratrol is attracting special attention because its biological activities are well-characterized, and many reports claim that it is valuable to human health and exhibits anti-aging effects. While an intrinsic component of plants, resveratrol is one of the antibacterial substances synthesized by vegetables, known as phytoalexins.
Resveratrol is produced when plants are infected by fungi or damaged, in order to defend themselves against fungi or damage. Resveratrol is attracting attention in the United States, as it is contained in grape skin and peanut seed coats, has a strong antioxidant effect, and is effective in preventing cancers and lifestyle diseases.
The following describes an example analysis of resveratrol.
Analysis of Resveratrol
Sample
Resveratrol
Standard solutions: Concentrations from 0.05 - 50 mg/L, prepared with methanol
Conditions
| Column | HITACHI LaChrom C18(5 µm) (4.6 mmI.D. x 150 mm) |
|---|---|
| Mobile phase | (A) 0.1 % H3PO4 (pH2.2) (B) CH3CN *Gradient: (0 min) B10% → (10 min) B10% → (30 min) B70% → (40 min) B70% → (40.1 min) B10% → (55 min) B10% |
| Flow rate | 1.0 mL/min |
| Column Temperature | 40°C |
| Detection | DAD 303 nm |
| Injection vol. | 10 µL |
System configuration
5110 Pump
5210 AutoSampler
5310 Column Oven
5430 Diode Array Detector
Empower2 Data Processing System
Analysis results of standard sample
Linearity
Standard Curve
A fairly linear standard curve was obtained in the concentration range between 0.05 - 50 mg/L.
trans-Resveratrol standard sample after UV irradiation
Identification of cis-resveratrol
Resveratrol has two isomers: trans and cis.
trans-Resveratrol is converted to cis-Resveratrol by UV or heat.
In this analysis, 10 mL of 50 mg/L transresveratrol was placed in a sample bottle, and irradiated with a UV disinfection lamp for 1 hour. The eluting position and spectrum of the cis-resveratrol formed by irradiation were identified.
Analysis example of a standard sample:Commercial red wine
Pretreatment method of the sample
*
Reference:
New Food Analysis Method[II] The Japanese Society for Food Science and Technology and Japanese Society for Food Analysis
Published on November 15, 2006, by Korin Publishing Co.
Commercial red wine
Comparison of the sample with and without a solid phase extraction process
(1) Sample: Commercial red wine
(2) Sample: Commercial white wine
w/ solid phase extraction process
Treated as described in the process flow above.
w/o solid phase extraction process
After adjustment to pH 7.0, as described in the process flow above, filtered with a 0.45 µm filter.
A sample with solid phase-extracted wine and a sample with non-processed wine were measured and the resulting chromatograms were compared.
As wine includes various components, a peak for resveratrol in a sample with nonprocessed red wine cannot be identified.
This result proves that pretreatment with solid phase extraction is effective.
Both red wine and white wine exhibited recovery rates of 94.0%, by standard addition.
Concentration of resveratrol in each wine
sample:Red wine: 1.1 mg/L, White wine: 0.24 mg/L
Resveratrol is contained in large amounts in grape skin. It was confirmed that red wine, when brewed from grapes retaining their skins, has a higher concentration of resveratrol.
NOTE:
These data are an example of measurement; the individual values cannot be guaranteed.
The system is for research use only, and is not intended for any animal or human therapeutic or diagnostic use.
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