In vitro investigation of the effect of different polarity solvent extracts of walnut inner shells on the enzyme pathway associated with plasma cholesterol level

Cholesterol is a critically important molecule for the functionality of cells, which are the building stones of organisms. Its excess and scarcity cause disruptions and damage to the cell membrane structure. In order to prevent these, the amount of cholesterol taken in the diet has kept balanced, and medical treatments are applied if necessary. In addition, the public also applies to natural and herbal products. In this study, which was designed based on the assumption that walnut inner shells have an effect on cholesterol, content analysis of walnut inner shell extracts prepared in solvents of different polarity was carried out in gas chromatography-mass spectrometry (GC-MS) and the effect of extracts on 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and cholesterol esterase was investigated in vitro. 5 g walnut inner shell was extracted separately in 50 ml distilled water, methanol, ethanol, acetone, hexane and cyclohexane solvents for twenty-four hours. Furthermore, a separate solution was prepared by boiling in distilled water for one hour. Samples were analyzed in GC-MS in helium mobile phase and gradual temperature increase, identification was made with the integrated library database. Dilute concentrations of each extract were prepared from 10 mg/mL stock solutions, the effect on HMG-CoA reductase and cholesterol esterase was determined colorimetrically in a multi-plate reader. In the GC-MS scanning, polyunsaturated fatty acid, terpene and phenolic compound derivatives were seen in distilled water, ethanol, methanol extracts, and saturated hydrocarbon (alkane) compounds in hexane, cyclohexane and acetone extracts. While % 3.2 inhibition effect on HMG-CoA reductase was seen at 2 μg/mL concentration of acetone extract, % 13.6 inhibition effect on cholesterol esterase was seen at 67 μg/mL concentration of the extract kept in distilled water for one day. In this thesis, it was determined in vitro that walnut inner shells had no effect on HMG-CoA reductase and cholesterol esterase, which are enzyme pathways related to plasma cholesterol levels.