Thelephoric acid is a terphenylquinone pigment

Pigment

A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...

 which is found in several fungi, such as Omphalotus subilludens and Polyozellus multiplex. Thelephoric acid has been shown to inhibit prolyl endopeptidase

Prolyl endopeptidase

Prolyl endopeptidase or prolyl oligopeptidase, sometimes post-proline cleaving enzyme) is a large cytosolic enzyme that belongs to a distinct class of serine peptidases. It was first described in the cytosol of rabbit brain as an oligopeptidase, which degrades the nonapeptide bradykinin at the...

, an enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that has a role in processing proteins (specifically, amyloid precursor protein

Amyloid precursor protein

Amyloid precursor protein is an integral membrane protein expressed in many tissues and concentrated in the synapses of neurons. Its primary function is not known, though it has been implicated as a regulator of synapse formation, neural plasticity and iron export...

) in Alzheimer's disease

Alzheimer's disease

Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...

. Chemicals that inhibit prolyl endopeptidase have attracted research interest due to their potential therapeutic effects.