Wednesday, July 06, 2011

New Method for Detecting Counterfeit Propolis

Development and Validation of HPLC Method for Determination of Salicin in Poplar Buds: Application for Screening of Counterfeit Propolis
Food Chemistry, Volume 127, Issue 1, 1 July 2011, Pages 345-350

The main plant origins of propolis are the populus species and their hybrids, both located in China. Poplar tree gum, the extract of populus buds, has been widely used as counterfeit propolis, but no efficient method was known for detecting the counterfeit.

Salicin is a characteristic marker of the genus populus, which may be hydrolysed by β-glucosidase during propolis collection and processing. A simple, sensitive and specific reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the rapid assay of salicin, which was aimed at distinguishing poplar tree gum from propolis. Isocratic elution at a flow rate of 1.0 mL/min was employed on a Sepax HP-C18 column (150 × 4.6 mm, 5 μm) and the column temperature was 30 °C. The mobile phase consisted of acetonitrile and 0.5% aqueous phosphoric acid (5:95, v/v). The UV detection wavelength was 213 nm.

Following this method, salicin was detected in populus buds and leaves and 11 poplar tree gum samples, but not in any of the 40 propolis samples, which indicates that salicin was hydrolysed in propolis collection and processing but was stable in the production process of poplar tree gum.

The proposed method could be an effective technique for routine analysis of salicin and monitoring the quality of propolis as possible counterfeit poplar tree gum. 

Research highlights

• A simple, sensitive and specific reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for distinguishing poplar tree gum from propolis.
• Salicin as a marker for HPLC fingerprint was proposed for the first time.
• The proposed method could be an effective technique for routine analysis of salicin and monitoring the quality of propolis as possible counterfeit poplar tree gum.

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