Protocatechuic acid is a dihydroxybenzoic acid

Dihydroxybenzoic acid

Dihydroxybenzoic acids are a type of phenolic acids.There are six main compounds, having all the same molecular formula C7H6O4. Those are:* 2,3-Dihydroxybenzoic acid * 2,4-Dihydroxybenzoic acid...

, a type of phenolic acid

Phenolic acid

Phenolic acids are a type of organic compounds. Included in that class are substances containing a phenolic ring and an organic carboxylic acid function ....

. It has mixed effects on normal and cancer cells in in vitro

In vitro

In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...

and in vivo

In vivo

In vivo is experimentation using a whole, living organism as opposed to a partial or dead organism, or an in vitro controlled environment. Animal testing and clinical trials are two forms of in vivo research...

studies.

Biological effects

PCA has been reported to induce apoptosis

Apoptosis

Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...

 of human leukemia

Leukemia

Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...

 cells, as well as malignant HSG1 cells taken from human oral cavities, but PCA was found to have mixed effects on TPA

12-O-Tetradecanoylphorbol-13-acetate

12-O-tetradecanoylphorbol-13-acetate , also commonly known as tetradecanoylphorbol acetate, tetradecanoyl phorbol acetate, and phorbol 12-myristate 13-acetate , is diester of phorbol and a potent tumor promoter often employed in biomedical research to activate the signal transduction enzyme protein...

-induced mouse skin tumours. Depending on the amount of PCA and the time before application, PCA could reduce or enhance tumour growth. Similarly, PCA was reported to increase proliferation and inhibit apoptosis of neural stem cell

Stem cell

This article is about the cell type. For the medical therapy, see Stem Cell TreatmentsStem cells are biological cells found in all multicellular organisms, that can divide and differentiate into diverse specialized cell types and can self-renew to produce more stem cells...

s. In an in vitro model using HL-60 leukemia

Leukemia

Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...

 cells, protocatechuic acid showed an antigenotoxic effect and tumoricidal activity.

Occurrence in nature

Açaí oil

Acai oil

Açaí oil is obtained from the fruit of Euterpe oleracea , which grows in the Amazon Rainforest. The oil is rich in phenolic compounds similar in profile to the pulp itself, such as vanillic acid, syringic acid, p-hydroxybenzoic acid, protocatechuic acid and ferulic acid as well as -catechin and...

, obtained from the fruit of the açaí Palm (Euterpe oleracea), is rich in protocatechuic acid (630 +/- 36 mg/kg). It is also found in Allium cepa (17,540 ppm).

Metabolism

Protocatechuic acid is one of the main catechins metabolite

Metabolite

Metabolites are the intermediates and products of metabolism. The term metabolite is usually restricted to small molecules. A primary metabolite is directly involved in normal growth, development, and reproduction. Alcohol is an example of a primary metabolite produced in large-scale by industrial...

s found in humans after consumption of green tea

Green tea

Green tea is made solely from the leaves of Camellia sinensis that have undergone minimal oxidation during processing. Green tea originates from China and has become associated with many cultures throughout Asia. It has recently become more widespread in the West, where black tea is traditionally...

 infusions.

Enzymes

Biosynthesis enzymes

• (3S,4R)-3,4-dihydroxycyclohexa-1,5-diene-1,4-dicarboxylate dehydrogenase
  (3S,4R)-3,4-dihydroxycyclohexa-1,5-diene-1,4-dicarboxylate dehydrogenase
  In enzymology, a -3,4-dihydroxycyclohexa-1,5-diene-1,4-dicarboxylate dehydrogenase is an enzyme that catalyzes the chemical reaction-3,4-dihydroxycyclohexa-1,5-diene-1,4-dicarboxylate + NAD+ \rightleftharpoons 3,4-dihydroxybenzoate + CO2 + NADH...
  
  
• Terephthalate 1,2-cis-dihydrodiol dehydrogenase
  Terephthalate 1,2-cis-dihydrodiol dehydrogenase
  In enzymology, a terephthalate 1,2-cis-dihydrodiol dehydrogenase is an enzyme that catalyzes the chemical reactionThus, the two substrates of this enzyme are cis-4,5-dihydroxycyclohexa-1,2-diene-1,4-dicarboxylate and NAD+, whereas its 3 products are 3,4-dihydroxybenzoate, CO2, and NADH.This enzyme...
  
  
• 3-hydroxybenzoate 4-monooxygenase
  3-hydroxybenzoate 4-monooxygenase
  In enzymology, a 3-hydroxybenzoate 4-monooxygenase is an enzyme that catalyzes the chemical reactionThe 4 substrates of this enzyme are 3-hydroxybenzoate, NADPH, H+, and O2, whereas its 3 products are 3,4-dihydroxybenzoate, NADP+, and H2O....
  
  
• 4-hydroxybenzoate 3-monooxygenase (NAD(P)H)
  4-hydroxybenzoate 3-monooxygenase (NAD(P)H)
  In enzymology, a 4-hydroxybenzoate 3-monooxygenase [NADH] is an enzyme that catalyzes the chemical reactionThe 5 substrates of this enzyme are 4-hydroxybenzoate, NADH, NADPH, H+, and O2, whereas its 4 products are 3,4-dihydroxybenzoate, NAD+, NADP+, and H2O.This enzyme belongs to the family of...
  
  
• 4-sulfobenzoate 3,4-dioxygenase
  4-sulfobenzoate 3,4-dioxygenase
  In enzymology, a 4-sulfobenzoate 3,4-dioxygenase is an enzyme that catalyzes the chemical reactionThe 4 substrates of this enzyme are 4-sulfobenzoate, NADH, H+, and O2, whereas its 3 products are 3,4-dihydroxybenzoate, sulfite, and NAD+....
  
  
• Vanillate monooxygenase
  Vanillate monooxygenase
  In enzymology, a vanillate monooxygenase is an enzyme that catalyzes the chemical reactionThe 4 substrates of this enzyme are vanillate, O2, NADH, and H+, whereas its 4 products are 3,4-dihydroxybenzoate, NAD+, H2O, and formaldehyde....
  
  
• 3,4-dihydroxyphthalate decarboxylase
  3,4-dihydroxyphthalate decarboxylase
  In enzymology, a 3,4-dihydroxyphthalate decarboxylase is an enzyme that catalyzes the chemical reactionHence, this enzyme has one substrate, 3,4-dihydroxyphthalate, and two products, 3,4-dihydroxybenzoate and CO2....
  
  
• 4,5-dihydroxyphthalate decarboxylase
  4,5-dihydroxyphthalate decarboxylase
  In enzymology, a 4,5-dihydroxyphthalate decarboxylase is an enzyme that catalyzes the chemical reactionHence, this enzyme has one substrate, 4,5-dihydroxyphthalate, and two products, 3,4-dihydroxybenzoate and CO2....
  
  

Degradation enzymes
The enzyme protocatechuate decarboxylase

Protocatechuate decarboxylase

In enzymology, a protocatechuate decarboxylase is an enzyme that catalyzes the chemical reactionHence, this enzyme has one substrate, 3,4-dihydroxybenzoate, and two products, catechol and CO2....

 uses 3,4-dihydroxybenzoate to produce catechol and CO₂

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

.

The enzyme protocatechuate 3,4-dioxygenase

Protocatechuate 3,4-dioxygenase

In enzymology, a protocatechuate 3,4-dioxygenase is an enzyme that catalyzes the chemical reactionThus, the two substrates of this enzyme are 3,4-dihydroxybenzoate and O2, whereas its product is 3-carboxy-cis,cis-muconate....

 uses 3,4-dihydroxybenzoate and O₂ to produce 3-carboxy-cis,cis-muconate.