Photocatalytic degradation of free cholesterol using UV light: Kinetics and clinical studies, in vitro

Cholesterol, a steroid compound, is a waxy molecule that is found in approximately all types of cells in the human body. A higher concentration of cholesterol in the blood is associated with cardiovascular disease, which causes atherosclerosis. Lowering cholesterol is the most frequently prescribed target for reducing morbidity and mortality related to heart disease. Here, the photocatalytic degradation of diluted serum from atherosclerosis patients (1:5, potassium phosphate buffer, pH 6.5: serum) over 48 hr was investigated, in vitro , by a UV-light-based catalyst (370 nm, 220 V, 56 W). The resulting species were characterized using an ultraviolet spectrophotometer and HPLC. The results showed that the maximum degradation of cholesterol (350 mg/dl) was 19.7%. The kinetics of degradation followed the pseudo first order and kinetic model with a constant rate (k) of (4.7x10 ^-3 min ^-1 ). The degradation was successfully confirmed by the formation of free fatty acids, for which the acid content was equal to 6.1 after degradation compared to its negligible value before degradation. On the other hand, the enzymatic degradation percentage of cholesterol (405 mg/dL) was also studied, and the results indicated 50% degradation after ~ one hour. Therefore, this study demonstrated that ultraviolet absorption can offer a feasible direction for the quantitative degradation of high concentrations of cholesterol. Photocatalysis is an alternative method for removing cholesterol from serum samples.