Characterisation of Taiwanese propolis collected from different locations and seasons

BACKGROUND: Characterisation of propolis is difficult because of the fact that its chemical composition can vary with its source of origin. The aim of this study was to establish distinctive criteria relating to quantifiable quality features of Taiwanese propolis (TP). Thirty-four samples of TP were collected from nine different locations in different seasons. Based on colour, the 34 samples were categorised into three groups, TW-I (green), TW-II (brownish green) and TW-III (dark brown). Ethanolic extracts of these samples were tested for dry extract yield, total phenolic content, propolin content, antiradical activity and antimicrobial activities. RESULTS: TW-I had a higher dry extract yield (71.5 +/- 6.0%), a higher total phenolic content and higher propolin levels than TW-II and TW-III. It also showed a stronger ability to scavenge 1,2-diphenyl-2-picryhydrazyl (DPPH) free radicals. Both TW-I and TW-II had higher antimicrobial activities than TW-III. CONCLUSION: The results indicated that the high biological activities of TW-I might be correlated with its high content of propolins. In summary, propolin content, colour and season might be useful as quality parameters of TP. (c) 2007 Society of Chemical Industry.