Lithocholic acid, also known as 3α-hydroxy-5β-cholan-24-oic acid or LCA, is a
bile acid
Bile acids are steroid acids found predominantly in the bile of mammals and other vertebrates. Diverse bile acids are synthesized in the liver. Bile acids are conjugated with taurine or glycine residues to give anions called bile salts.
Primary b ...
that acts as a detergent to solubilize fats for absorption. Bacterial action in the
colon produces LCA from
chenodeoxycholic acid
Chenodeoxycholic acid (CDCA; also known as chenodesoxycholic acid, chenocholic acid and 3α,7α-dihydroxy-5β-cholan-24-oic acid) is a bile acid. Salts of this carboxylic acid are called chenodeoxycholates. Chenodeoxycholic acid is one of the mai ...
by reduction of the
hydroxyl
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...
functional group at carbon-7 in the "B" ring of the
steroid
A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and a ...
framework.
It has been implicated in human and experimental animal carcinogenesis.
Preliminary ''
in vitro
''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology an ...
'' research suggests that LCA selectively kills
neuroblastoma
Neuroblastoma (NB) is a type of cancer that forms in certain types of nerve tissue. It most frequently starts from one of the adrenal glands but can also develop in the neck, chest, abdomen, or spine. Symptoms may include bone pain, a lump in the ...
cells, while sparing normal neuronal cells and is cytotoxic to numerous other malignant cell types at physiologically relevant concentrations.
Dietary fiber
Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by the ...
can bind to lithocholic acid and aid in its excretion in stool; as such, fiber can protect against colon cancer.
LCA (and LCA acetate and LCA propionate) can activate the
vitamin D receptor
The vitamin D receptor (VDR also known as the calcitriol receptor) is a member of the nuclear receptor family of transcription factors. Calcitriol (the active form of vitamin D, 1,25-(OH)2vitamin D3) binds to VDR, which then forms a heterodimer ...
without raising calcium levels as much as
vitamin D
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. In humans, the most important compounds in this group are vitamin D3 (c ...
itself.
LCA binds with high affinity (20 μM) to the human membrane enzyme
NAPE-PLD NAPE-PLD may refer to:
* N-acyl phosphatidylethanolamine-specific phospholipase D, an enzyme
* N-acetylphosphatidylethanolamine-hydrolysing phospholipase D, an enzyme
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