Determination of flavanoid, antioxidant and trace element levels in extractions of jujube (Zizyphus jujuba Mill) fruits using different methods and its effect on acetylcholinesteras activity

Jujube (Zizyphus jujuba Mill.), a medicinal plant, has a functional role in human health with the various metabolites and minerals it contains. The aim of the thesis is to examine the amount of flavonoids and antioxidants which are the metabolites contained in jujube in water and alcohol extracts separately and to investigate the amounts and types of trace elements. It was also aimed to determine the inhibition effect of jujube on the acetylcholinesterase enzyme. Jujube fruits were dried in an oven at 50 oC. Then, alcohol and water extractions were prepared with the help of a lyophilizer device. Commercially available TAS-TOS kits were used to calculate the antioxidant amounts of jujube. Analysis of flavonoid substance amounts was determined using the spectrophotometric method. Determination of the trace element levels contained in jujube was measured with the ICP-MS device. Spectrophotometric measurement results were compared with tacrine, an acetylcholinesterase inhibitor, using the Ellman method for acetylcholinesterase enzyme inhibition. 10 separate measurements of water and alcohol extracts of jujube were made in order to measure the flavonoid amounts of jujube. According to the results, the average amount of total flavonoids in the alcohol extract of jujube was 0.71 µg/ml and the average amount of total flavonoids in the water extract was 2.24 µg/ml. The total amount of flavonoids in the water extract was found to be higher and significant than in the alcohol extract (p<0.05). 10 measurements each of water and alcohol extracts were made to determine the total antioxidant and oxidant amounts of jujube. It was found that the average total oxidant level (TOS) of jujube in water extract is 11.25 μmol/L, the average in alcohol extract is 78.57 μmol/L while the average total antioxidant level (TAS) of jujube was calculated as 0.96 μmol/L in water extract and 2.87 μmol/L in alcohol extract. Total antioxidant and oxidant status of jujube were found to be higher and significant in alcohol extracts (p<0.05). ICP-MS device was used to determine the trace element levels contained in jujube. Two different measurements of water and alcohol extractions were taken separately. Measurements of jujube in terms of 9 different trace elements were analyzed. Of the 9 trace elements, except for cobalt, the trace element levels in the water extracts of jujube were found to be higher than the alcohol trace element levels. The element cobalt was not detected. The jujube ethanol extraction was found as AChE R2 0,9917, İc50:0,002962 while jujube water extraction was R2 0,9945, İc50:0,002254 in acetylcholinesterase inhibition. As a result of the analysis, it was found that the fruits of the jujube plant function as a functional food thanks to the metabolites it contains and the enzyme inhibition values are lower than tacrine, an acetylcholinesterase inhibitor. It has been concluded that jujube has beneficial effects on human health thanks to the phytochemicals it contains, but the number of studies carried out needs to be increased in more detail. Key words: Acetylcholinesterase, antioxidant, flavonoid, jujube, trace element