Investigation of antioxidant activity of black cumin honey supplied from izmir by spectrophotometric and electrochemical methods

The use of natural foods in daily nutrition has increased significantly in the modern world. These foods contain a variety of antioxidant compounds, including flavonoids and phenolic acids, which have beneficial effects on human health. Honey, a completely natural food, is among the most frequently evaluated foods because it provides nutritional antioxidants in a highly palatable form. Chestnut, thyme, heather, blackthorn, rhododendron, linden, clover, astragalus, sunflower, naringin, and cotton honeys are among the most intensively researched monofloral honeys. Pine, oak, and cedar honeys are the most extensively studied. Despite being a valuable monofloral honey, Nigella sativa L. honey has received less research in the literature, both chemically and biochemically. In this thesis, the total phenolic and flavonoid contents of five different black cumin honeys obtained from the Bucak district of Izmir were investigated, along with their spectroscopic antioxidant activities based on their potential for DPPH radical scavenging, Fe2+ chelation, and catalase enzyme activity. Their antioxidant activities were also investigated electrochemically, compared to gallic acid and ascorbic acid. The potential therapeutic effects of black cumin honey on neurological diseases were investigated by determining the cholinesterase inhibitory activity of honey samples. Furthermore, their potential to prevent radical damage to plasmid DNA was demonstrated by agarose gel electrophoresis. While the total phenolic contents, DPPH radical scavenging, and catalase activities of the five samples examined were almost identical, honey number IV was richer in total flavonoid content. The same honey was also found to inhibit acetylcholine esterase to a greater degree than the others. Electrochemical antioxidant activity studies concluded that honey number I yielded higher results. The finding that this sample exhibited the highest phenolic content, 0.787 mg GAE per gram of honey, and the most effective radical scavenging activity, with an IC50 value of 9.84 mg/mL, supports the findings of spectroscopic and electrochemical antioxidant studies. Furthermore, the damage caused to plasmid DNA by hydroxyl ion radicals generated by the Fenton reaction was equally repaired by all honey samples, as demonstrated by the rate of DNA fragmentation to a superhelical form on agarose gel electrophoresis. As a result of this thesis study, which was planned and carried out with the idea that honey samples originating from the black cumin plant, which is known to have many health benefits, could be equally useful, it was concluded that the results of the study, which is a preliminary study, will create interest in black cumin honey, which is rarely examined in the literature compared to other honey types, and that it has an important candidate potential for natural medicine searches with further planned studies.