Application of FTIR fingerprints coupled with chemometric for comparison of stingless bee propolis from different extraction methods

Abstract

Propolis is a mixture of resin collected by the bees to build their hive. These mixtures contain natural remedy and used to treat variety of health-related problems. Unlike honeybee propolis, the study of stingless bee propolis still lacking. The important part of propolis study is the optimization of extraction procedures. The aim for this study is to employ chemometrics on FTIR data in order to discriminate the chemical fingerprinting of Malaysian stingless bee, Heterotrigona itama propolis yielded from different extraction methods, which were maceration, sonication and soxhlet. The chemical fingerprinting was obtained through Fourier Transform Infrared (FTIR). Principle component analysis (PCA) and hierarchical cluster analysis (HCA) were applied as pattern recognition methods for FTIR spectra. PCA of FTIR data for different extraction methods of stingless bee’s propolis revealed that variability of PC1 and PC2 is 84.76%. PCA’s variation in propolis by different extraction methods was classified based on specific functional groups arisen from the peaks. The FTIR fingerprinting of HCA of stingless bee’s propolis were distributed into three clusters based on percentages of ethanol, intensity of peaks and different fingerprint region. FTIR coupled with chemometric analysis showed classification of different extraction methods of propolis from PCA and HCA based on vibration of functional groups presence in the samples. Taken together, these results showed that different extraction methods play important role in detaining of chemical in propolis of stingless bee.