Determination of the phenolic composition and bioavailability of honey, pollen and propolis, important beekeeping products manufactured in different regions of Turkey, and the investigation of some effects of these beekeeping products on health by in vitro methods

In this thesis, it was aimed to determine the phenolic composition and bioaccessibility of honey, pollen and propolis, important beekeeping products produced in different regions of Turkey, and to investigate some effects of these beekeeping products on health by in vitro methods, and to reveal the place and importance of these products in nutrition. For this purpose, the 50 honey, 50 pollen and 50 propolis samples were obtained for 2 years, 25 samples each year, from 7 different geographical regions of Turkey and some chemical contents, phenolic compositions, antioxidant, antibacterial, and anti-inflammatory effects were determined, and their effects on health were also revealed by in vitro methods, and the cytotoxic effects of selected samples of these beekeeping products against some cancer cells were investigated. It was determined that 31 monofloral and 19 multifloral honey samples and 29 monofloral and 21 multifloral pollen samples were obtained according to the results of pollen analysis. The results of the diastase number, HMF and proline contents of honey, performed to evaluate the naturality and freshness of the honey samples, were found to vary in the ranges of 0.79-72.41, 0.72-65.61 mg/kg and 261.10-1408.12 mg/kg, respectively, and it was evaluated that the results mostly in accordance with the legal limits. The phenolic content of honey, pollen and propolis samples were determined as 13.00-132.07, 338.15-2857.77 and 508.35-25999.87 mg GAE/100g, respectively. When the phenolic composition analysis results were examined, the mean values of gallic acid, methyl-3,4,5-trihydroxybenzoate and naringin concentrations of honey samples were higher (>2.0 mg/100g) than other phenolic compounds while trans cinnamic acid, apigenin, myricetin, quercetin and luteolin were found to be lower (<0.07 mg/100g). The mean content of rosmarinic acid, naringenin, rutin and apigenin of pollen samples were higher than other phenolic compounds with 155.38, 51.91, 34.31 and 29.16 mg/100g values, respectively, while their syringic, vanillic, gallic and ferulic acid contents were lower (<0.8 mg/100g). The mean values of rosmarinic acid, caffeic acid, 3,4-dimethoxycinnamic acid, ferulic acid and naringenin of propolis samples were higher than other phenolic compounds with 737.42, 317.31, 285.49, 255.50 and 246.92 mg/100g values, respectively, while methyl-3,4,5-trihydroxybenzoate, syringic acid, vanillic acid, hesperidin, rutin and myricetin contents were determined to be lower (<7.0 mg/100g). It was detected that a classification could be made between regions according to the phenolic compound composition with an accuracy rate of 58% in honey samples, 70% in pollen samples, and 74% in propolis samples according to the results of the linear discriminant analysis. Pollen samples from Aegean (83.3%), Central Anatolia (71.4%), Black Sea (77.8%) and Marmara (75.0%) regions and propolis samples from Mediterranean (100%), Eastern Anatolia (75.0%), Aegean (71.4%), Black Sea (85.7%) and Marmara (71.4%) regions can be classified in terms of phenolic compound compositions, but the other regions are intertwined because the results are close to each other. It was determined that the phenolic component bioaccessibility values in the digested honey samples were 260% higher than the undigested honey samples, but it was lower in digested pollen and propolis samples than the undigested pollen and propolis samples with an average of 78.93% and 34.55%, respectively. However, it was determined that the total phenolic and flavonoid contents and accordingly, the bioaccessibility values and antioxidant activities of the samples increased from the oral digestion phase to the intestinal digestion phase. In addition, it was determined that the inhibitory effects of the selected digested propolis samples on cancer cells were higher than the other samples, and the cell-inhibitory effect of honey, pollen and propolis samples was A549, Hep-G2, Caco-2, H1299, A431 and Bj cells, respectively. As a result, it was evaluated that phenolic compounds could be used as a parameter in the classification of regions for pollen and propolis samples, phenolic compound bioaccessibility after digestion was high for honey, nearly the same for pollen but low for propolis, and the selected digested samples had inhibitory effects on cancer cells used in the research.