Lithocholic acid, also known as 3α-hydroxy-5β-cholan-24-oic acid or LCA, is a bile acid that acts as a detergent to solubilize fats for absorption. Bacterial action in the colon produces LCA from chenodeoxycholic acid by reduction of the hydroxyl functional group at carbon-7 in the "B" ring of the steroid framework.[citation needed]
It has been implicated in human and experimental animal carcinogenesis.[2][3] Preliminary in vitro research suggests that LCA selectively kills neuroblastoma cells, while sparing normal neuronal cells and is cytotoxic to numerous other malignant cell types at physiologically relevant concentrations.[4]
Dietary fiber can bind to lithocholic acid and aid in its excretion in stool;[5] as such, fiber can protect against colon cancer.
LCA (and LCA acetate and LCA propionate) can activate the vitamin D receptor without raising calcium levels as much as vitamin D itself.[6]
LCA binds with high affinity (20 μM) to the human membrane enzyme NAPE-PLD, enhancing dimer assembly and enabling catalysis. NAPE-PLD catalyzes the release of anandamide and other N-acylethanolamines (NAE) from the membrane precursor N-acylphosphatidylethanolamine (NAPE). NAPE-PLD facilitates crosstalk between bile acid signals and lipid amide signals.[7][8][9]
LCA was also shown to have anti-aging effects in a yeast study.[10][11] A later study showed that the bile acid accumulates in the inner and outer mitochondrial membranes, altering the mitochondria's lipid composition by promoting or inhibiting various enzymes.[12]
^Kozoni, V.; Tsioulias, G; Shiff, S; Rigas, B (2000). "The effect of lithocholic acid on proliferation and apoptosis during the early stages of colon carcinogenesis: Differential effect on apoptosis in the presence of a colon carcinogen". Carcinogenesis. 21 (5): 999–1005. doi:10.1093/carcin/21.5.999. PMID10783324.
^Zeng H, Umar S, Rust B, Lazarova D, Bordonaro M. Secondary Bile Acids and Short Chain Fatty Acids in the Colon: A Focus on Colonic Microbiome, Cell Proliferation, Inflammation, and Cancer. Int J Mol Sci. 2019 Mar 11;20(5):1214. doi:10.3390/ijms20051214PMID30862015