Probiotic microorganisms have been documented over the past two decades to play a role in
cholesterol-lowering properties via various clinical trials. Several mechanisms have also been proposed and the ability of these microorganisms to deconjugate bile via production of
bile salt hydrolase (BSH) has been widely associated with their
cholesterol lowering potentials in prevention of
hypercholesterolemia. Deconjugated
bile salts are more hydrophobic than their conjugated counterparts, thus are less reabsorbed through the intestines resulting in higher excretion into the feces. Replacement of new
bile salts from
cholesterol as a precursor subsequently leads to decreased serum
cholesterol levels. However, some controversies have risen attributed to the activities of deconjugated
bile acids that repress the synthesis of
bile acids from
cholesterol. Deconjugated
bile acids have higher binding affinity towards some
orphan nuclear receptors namely the farsenoid X receptor (FXR), leading to a suppressed transcription of the
enzyme cholesterol 7-alpha
hydroxylase (7AH), which is responsible in
bile acid synthesis from
cholesterol. This notion was further corroborated by our current docking data, which indicated that deconjugated
bile acids have higher propensities to bind with the FXR receptor as compared to conjugated
bile acids.
Bile acids-activated FXR also induces transcription of the IBABP gene, leading to enhanced recycling of
bile acids from the intestine back to the liver, which subsequently reduces the need for new bile formation from
cholesterol. Possible detrimental effects due to increased deconjugation of
bile salts such as malabsorption of
lipids, colon
carcinogenesis,
gallstones formation and altered gut microbial populations, which contribute to other varying gut diseases, were also included in this review. Our current findings and review substantiate the need to look beyond BSH deconjugation as a single factor/mechanism in strain selection for
hypercholesterolemia, and/or as a sole mean to justify a
cholesterol-lowering property of probiotic strains.