Evaluation of phenolic profile, botanical origin, antioxidant and antimicrobial activities of Turkish propolis

Propolis is a bee product having complex chemical composition and wide spectrum of biological activities. This study evaluated the phenolic profile of Turkish propolis by using an high performance thin-layer chromatographic (HPTLC) method. Also, the botanical origins of propolis samples were determined by comparison of HPTLC fingerprints of propolis samples and plant bud extracts. As a result, Turkish propolis could be categorized into 3 main types: orange (O) type, blue (B) type and 3-O-methylquercetin (3MQ) type. O and B-types originated from Populus nigra L., P. tremula L., respectively. In addition, HPTLC combined with 2,2-diphenyl-1-picrylhydrazyl (DPPH˙) test was used to evaluate antioxidant activity of separated compounds on the HPTLC plate. The results of HPTLC-DPPH˙ showed that separated compounds in O-type of propolis had a higher radical scavenging effect than the other types when compared the zone areas which had an antioxidant capacity. CAPE (Caffeic acid phenethyl ester), caffeic acid, galangin, kaempferol and quercetin were contributed propolis antioxidant activity. Moreover, comparative antimicrobial activity against strains of Streptococcus aureus, Pseudomonas aureginosa, Escherichia coli and Candida albicans was determined by disc diffusion test and minimum inhibitory concentration (MIC) assay on O-, B- and 3MQ-types. Consequently, P17 (B-type) and P19 (O-type) showed the highest antimicrobial activity against E. coli and C. albicans. Lastly, total phenol content (TPC) and total flavonoid content (TFC) of propolis samples were evaluated by spectrophotometry. TPC and TFC values were found to be highest in O-type.