Ferulic acid is a

hydroxycinnamic acid Hydroxycinnamic acids (hydroxycinnamates) are a class of aromatic acids or phenylpropanoids having a C6–C3 skeleton. These compounds are hydroxy derivatives of cinnamic acid. In the category of List of phytochemicals in food, phytochemicals tha ...

derivative In mathematics, the derivative is a fundamental tool that quantifies the sensitivity to change of a function's output with respect to its input. The derivative of a function of a single variable at a chosen input value, when it exists, is t ...

and a phenolic compound. It is an organic compound with the formula (CH₃O)HOC₆H₃CH=CHCO₂H. The name is derived from the genus '' Ferula'', referring to the giant fennel ('' Ferula communis''). Classified as a phenolic

phytochemical Phytochemicals are naturally-occurring chemicals present in or extracted from plants. Some phytochemicals are nutrients for the plant, while others are metabolites produced to enhance plant survivability and reproduction. The fields of ext ...

, ferulic acid is an amber colored solid. Esters of ferulic acid are found in plant

cell walls A cell wall is a structural layer that surrounds some cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, and functi ...

, covalently bonded to

hemicellulose A hemicellulose (also known as polyose) is one of a number of heteropolymers (matrix polysaccharides), such as arabinoxylans, present along with cellulose in almost all embryophyte, terrestrial plant cell walls. Cellulose is crystalline, strong, an ...

such as

arabinoxylan Arabinoxylan is a form of the hemicellulose xylan found in both the primary and secondary cell walls of plants which in addition to xylose contains substantial amounts of another pentose sugar, arabinose.Scheller, H. V., & Ulvskov, P. (2010). Hem ...

s. Salts and esters derived from ferulic acid are called ferulates.

Occurrence in nature

Ferulic acid is ubiquitous in the plant kingdom, including a number of vegetable sources. It occurs in particularly high concentrations in

popcorn Popcorn (also called popped corn, popcorns, or pop-corn) is a variety of corn kernel which expands and puffs up when heated. The term also refers to the snack food produced by the expansion. It is one of the oldest snacks, with evidence of p ...

and bamboo shoots. It is a major metabolite of

chlorogenic acid Chlorogenic acid (CGA) is the ester of caffeic acid and quinic acid, functioning as an intermediate in lignin biosynthesis. The term chlorogenic acids refers to a related polyphenol family of esters, including hydroxycinnamic acids ( caffeic a ...

s in humans along with caffeic and isoferulic acid, and is absorbed in the

small intestine The small intestine or small bowel is an organ (anatomy), organ in the human gastrointestinal tract, gastrointestinal tract where most of the #Absorption, absorption of nutrients from food takes place. It lies between the stomach and large intes ...

, whereas other metabolites such as dihydroferulic acid, feruloylglycine and dihydroferulic acid sulfate are produced from chlorogenic acid in the

large intestine The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the Digestion, digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces befor ...

by the action of

gut flora Gut microbiota, gut microbiome, or gut flora are the microorganisms, including bacteria, archaea, fungi, and viruses, that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the g ...

. In cereals, ferulic acid is localized in the

bran Bran, also known as miller's bran, is the component of a Cereal, cereal grain consisting of the hard layersthe combined aleurone and Fruit anatomy#Pericarp layers, pericarpsurrounding the endosperm. Maize, Corn (maize) bran also includes the p ...

– the hard outer layer of grain. In

wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...

, phenolic compounds are mainly found in the form of insoluble bound ferulic acid and may be relevant to resistance to wheat fungal diseases. The highest known concentration of ferulic acid

glucoside A glucoside is a glycoside that is chemically derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes. Th ...

has been found in

flaxseed Flax, also known as common flax or linseed, is a flowering plant, ''Linum usitatissimum'', in the family Linaceae. It is cultivated as a food and fiber crop in regions of the world with temperate climates. In 2022, France produced 75% of the ...

(). It is also found in

barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ...

grain. Asterid eudicot plants can also produce ferulic acid. The tea brewed from the leaves of

yacón The yacón (''Smallanthus sonchifolius'') is a species of daisy traditionally grown in the northern and central Andes from Colombia to northern Argentina for its crisp, sweet-tasting, tuberous roots. Their texture and flavour are very similar t ...

(''Smallanthus sonchifolius''), a plant traditionally grown in the northern and central

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

, contains quantities of ferulic acid. In

legume Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consum ...

s, the white bean variety

navy bean The navy bean, haricot bean, Jigna bean, pearl haricot bean, Boston bean, white pea bean, or pea bean is a variety of the common bean (''Phaseolus vulgaris'') native to the Americas, where it was first domesticated. It is a dry white bean that ...

is the richest source of ferulic acid among the common bean (''

Phaseolus vulgaris ''Phaseolus vulgaris'', the common bean,, is a herbaceous annual plant grown worldwide for its edible dry seeds or green, unripe pods. Its leaf is also occasionally used as a vegetable and the straw as fodder. Its botanical classification, alo ...

'') varieties. It is also found in horse grams (''Macrotyloma uniflorum''). Although there are many sources of ferulic acid in nature, its

bioavailability In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation. By definition, when a medication is administered intravenously, its bioavailability is 100%. H ...

depends on the form in which it is present: free ferulic acid has limited solubility in water, and hence poor bioavailability. In wheat grain, ferulic acid is found bound to

cell wall A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, ...

polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wat ...

s, allowing it to be released and absorbed in the small intestine.

In processed foods

Cooked sweetcorn releases increased levels of ferulic acid. As plant sterol

ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

s, this compound is naturally found in

rice bran oil Rice bran oil is the oil extracted from the hard outer brown layer of rice called bran. It is known for its high smoke point of and mild flavor, making it suitable for high-temperature cooking methods such as stir frying and deep frying. It i ...

, a popular cooking oil in several Asian countries. Ferulic acid

can be found in commercial

bread Bread is a baked food product made from water, flour, and often yeast. It is a staple food across the world, particularly in Europe and the Middle East. Throughout recorded history and around the world, it has been an important part of many cu ...

s containing

. Rye bread contains ferulic acid dehydrodimers.

Metabolism

Biosynthesis

Ferulic acid is biosynthesized in plants from

caffeic acid Caffeic acid is an organic compound with the formula . It is a polyphenol with a key role in scavenging reactive oxygen species (ROS) generated in energy metabolism. Caffeic acid is also one major polyphenol responsible for maintaining normal le ...

by the action of the enzyme caffeate ''O''-methyltransferase. In a proposed ferulic acid biosynthetic pathway for ''

Escherichia coli ''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Escherichia'' that is commonly fo ...

'', L-tyrosine is converted to 4-coumaric acid by tyrosine ammonia lyase, which is converted to caffeic acid by Sam5, which is then converted to ferulic acid by caffeic acid methyltransferase. Ferulic acid, together with dihydroferulic acid, is a component of

lignocellulose Lignocellulose refers to plant dry matter (biomass), so called lignocellulosic biomass. It is the most abundantly available raw material on the Earth for the production of Biofuel, biofuels. It is composed of two kinds of carbohydrate polymers, c ...

, serving to crosslink the lignin and polysaccharides, thereby conferring rigidity to the cell walls. It is an intermediate in the synthesis of

monolignol Monolignols, also called lignols, are the source materials for biosynthesis of both lignans and lignin and consist mainly of paracoumaryl alcohol (H), coniferyl alcohol (G) and sinapyl alcohol (S). These monolignols differ in their degree of meth ...

s, the monomers of

lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidit ...

, and is also used for the synthesis of

lignan The lignans are a large group of low molecular weight polyphenols found in plants, particularly seeds, whole grains, and vegetables. The name derives from the Latin word for "wood". Lignans are precursors to phytoestrogens. They may play a rol ...

Biodegradation

Ferulic acid is converted by certain strains of yeast, notably strains used in brewing of

wheat beer Wheat beer is a top-fermented beer which is brewed with a large proportion of wheat relative to the amount of malted barley. The two main varieties are German and Belgian ; other types include Lambic (made with wild yeast), Berliner Weisse (a c ...

s, such as ''Saccharomyces delbrueckii'' (''Torulaspora delbrueckii''), to 4-vinyl guaiacol (2-methoxy-4-vinylphenol) which gives beers such as Weissbier and Wit their distinctive clove-like flavour. ''

Saccharomyces cerevisiae ''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungal microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have be ...

'' (dry baker's yeast) and ''

Pseudomonas fluorescens ''Pseudomonas fluorescens'' is a common Gram-negative, rod-shaped bacterium. It belongs to the ''Pseudomonas'' genus; 16S rRNA analysis as well as phylogenomic analysis has placed ''P. fluorescens'' in the ''P. fluorescens'' group within the genu ...

'' are also able to convert ''trans''-ferulic acid into 2-methoxy-4-vinylphenol. In ''P. fluorescens'', a ferulic acid decarboxylase has been isolated.

Ecology

Ferulic acid is one of the compounds that initiate the ''vir'' (virulence) region of ''

Agrobacterium tumefaciens ''Agrobacterium tumefaciens'' (also known as ''Rhizobium radiobacter'') is the causal agent of crown gall disease (the formation of tumours) in over 140 species of eudicots. It is a rod-shaped, Gram-negative soil bacterium. Symptoms are cause ...

'', inducing it to infect plant cells.

Extraction

It can be extracted from wheat bran and maize bran using concentrated alkali. Ferulicacidspectrum

References

{{Hydroxycinnamic acid Phenol antioxidants O-methylated hydroxycinnamic acids Bitter-masking compounds Vinylogous carboxylic acids