Evaluation of Phenolic Compounds in Cistus creticus Bee Pollen from Greece. Antioxidant and Antimicrobial Properties

Abstract

This study was carried out to evaluate the antioxidant properties of Greek endemic Cistus creticus L. (rock rose) bee pollen and define its phenolic compounds. In the framework of our scientific studies on Greek bee keeping products, we report herein our research on three Greek bee pollen samples from Cistus. Their pollinic spectra were obtained by Louveaux's quantitative microscopical analysis and it showed that one of them had Cistus sp. (Cistaceae) as abundant pollen (together with low percentage of Brassica sp. (Cruciferae). Throughout the chemical analysis of the extracts, several secondary metabolites of flavonoid structure have been identified as major components. Specifically, quercetin-7-rhamnoside (1), quercetin-3-neohesperidoside (2), kaempferol-3neohesperidoside (3), myricetin-3-neohesperidoside (4), kaempferol-3-glucoside (5) and quercetin-3-glucoside (6) have been isolated and their structures were elucidated on the basis of spectral evidence. Moreover, the total phenolic and flavonoid content was estimated and the free radical scavenging activity was determined by DPPH and ABTS assays. The antimicrobial activity of the extracts was tested against six Gram-positive and-negative bacteria and three pathogenic fungi, and the butanol extract showed a very interesting broad antimicrobial profile (MIC 1.98•10-3-2.98•10-3 mg/ml) against all the assayed microorganisms.

Antimicrobial Activity of Bee-Collected Pollen and Beebread: State of the Art and Future Perspectives

“…This antibacterial activity was similar to antibiotics [ 155 ]. MIC values comparable to that of antibiotics were also reported for BCP extracts derived from the Greek endemic plant Cistus creticus L. (rock rose) [ 169 ].…”

Antioxidant Activity in Bee Products: A Review

“…Table 3 summarizes the results of the most recent publications on pollen and bee bread AOA [ 6 , 21 , 89 , 118 , 121 , 123 , 124 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 ]. As indicated for honey, there is usually a positive correlation between TPC, TFC and AOA, but similar TPC and TFC content does not always correspond to similar antioxidant capacity [ 43 , 78 ], as the overall antioxidant capacity of each sample is the result of the combined activity of phenolic and nonphenolic compounds [ 21 ].…”

Processing Technologies for Bee Products: An Overview of Recent Developments and Perspectives

“…The extraction procedure for the phenolics and flavonoids was primarily via solvent extraction using alcohol (methanol or ethanol) and water mixture (76,(250)(251)(252)(253); cyclohexane, dichloromethane, butanol, and water (254); petroleum ether, n-butanol, ethyl acetate, and water (255); and acidified water (256). As for the phenolic and flavonoid contents in bee products, the Folin-Ciocalteu method (57,254,(257)(258)(259) has been predominantly employed. The TFC of the BCP extracts was established (UV-Vis) in most cases using the aluminum trichloride colorimetric assay at 510 nm (253,260) or aluminum nitrate at 415 nm (57,258).…”