Cholesterol-lowering activity by lactic acid bacteria isolated from yogurt from Boyolali, Indonesia

Abstract. Nurcahyani I, Susilowati A, Pangastuti A. 2023. Cholesterol-lowering activity by lactic acid bacteria isolated from yogurt from Boyolali, Indonesia. Asian J Nat Prod Biochem 21: 34-45. Hypercholesterolemia is considered a risk factor for cardiovascular disease, as it is characterized by increased cholesterol levels in the bloodstream that exceed the established normal range. At present, cardiovascular disease stands as the foremost cause of mortality worldwide, with a global death toll of 17.7 million. The employment of Lactic Acid Bacteria as a probiotic has the potential to reduce cholesterol levels via the enzymatic of Bile Salt Hydrolase (BSH), which facilitates the deconjugation of bile salts, as well as its capacity to assimilate cholesterol directly. The consumption of fermented dairy products that have undergone appropriate bacterial fermentation has been found to potentially contribute to a reduction in blood cholesterol. The region of Boyolali in Indonesia is known for its yogurt production; regularly consuming probiotic products has been suggested as a dietary approach to promoting long-term hypocholesterolemia effects. The objective of this research was to isolate and evaluate the efficacy of Lactic Acid Bacteria (LAB) in reducing cholesterol levels, and to identify the specific isolates derived from yogurt originating from Boyolali. The activity of the BSH enzyme was evaluated through qualitative testing by observing precipitation zones on the growth media. A quantitative assessment was also conducted using the UV-vis spectrophotometer method at ?570 nm. LAB isolates' activity in bile salt deconjugation and cholesterol assimilation was also measured using the UV-vis spectrophotometer method at ?660 nm and ?550 nm, respectively. The bacterial identification process was conducted through the examination of both macroscopic and microscopic morphology. The study employed a One-way Analysis of Variance (ANOVA) to compare the release of amino acids (specifically glycine and taurine), the release of free cholic acid, and the disparity in cholesterol levels between media that were inoculated with LAB and those that were not. The BSH enzyme activity was observed to be 1.11-3.82 U/mL for sodium glycocholate substrate and 0.85-3.13 U/mL for sodium taurocholic substrate. The recorded levels of bile salt activity were 0.52-1.26 µmol/mL for the sodium glycocholate substrate and 0.43-0.9 µmol/mL for the sodium taurocholic substrate. The percentage of assimilated cholesterol ranges from 38.69% to 71.98%.