Ferulic acid is a hydroxycinnamic acid, an organic compound with the formula (CH₃O)HOC₆H₃CH=CHCO₂H. The name is derived from the genus ''

Ferula ''Ferula'' (from Latin ''ferula'', 'rod') is a genus of about 220 species of flowering plants in the family Apiaceae, native to the Mediterranean region east to central Asia, mostly growing in arid climates. They are herbaceous perennial plants ...

'', referring to the giant fennel ('' Ferula communis''). Classified as a phenolic

phytochemical Phytochemicals are chemical compounds produced by plants, generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals. The name comes . Some phytochemicals have been used as poison ...

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

cell walls A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mech ...

, covalently bonded to hemicellulose such as arabinoxylans.

Occurrence in nature

As a building block of lignocelluloses, such as

pectin Pectin ( grc, πηκτικός ': "congealed" and "curdled") is a heteropolysaccharide, a structural acid contained in the primary lamella, in the middle lamella, and in the cell walls of terrestrial plants. The principal, chemical component o ...

and

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 rigidity a ...

, 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 same names also refer to the foodstuff produced by the expansion. A popcorn kernel's strong hull contains the se ...

and bamboo shoots. It is a major metabolite of chlorogenic acids in humans along with caffeic and

isoferulic acid Isoferulic acid is a hydroxycinnamic acid, a type of organic compound. It is an isomer of ferulic acid. Occurrence in nature Isoferulic acid can be found, amongst other compounds, in ''Lobelia chinensis''. In food Ferulic acid is found in pin ...

, 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 digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before bein ...

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 gut m ...

. In cereals, ferulic acid is localized in the bran – the hard outer layer of grain. In

wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...

, 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 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. The name was ...

has been found in flaxseed (). It is also found in

barley Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley p ...

grain. Asterid

eudicot The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non-magnoliid dico ...

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

yacón The yacón (''Smallanthus sonchifolius'') is a species of perennial 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 ver ...

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

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

, contains quantities of ferulic acid. In

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock for ...

s, the white bean variety

navy bean The navy bean, haricot, 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 smaller than m ...

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, ...

'') varieties. It is also found in

horse gram ''Macrotyloma uniflorum'' (horsegram, also known as horse gram, kulthi bean, gahat, hurali, or Madras gram) is a legume native to tropical southern Asia, known for its distinct taste and texture, widely used legume in many cuisines. It is also k ...

s (''Macrotyloma uniflorum''). Although there are many sources of ferulic acid in nature, its bioavailability 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 surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mec ...

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 w ...

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

In herbal medicines

Ferulic acid has been identified in Chinese medicine herbs such as ''

Angelica sinensis ''Angelica sinensis'', commonly known as ''dong quai'' () or female ginseng, is a herb belonging to the family Apiaceae, indigenous to China. ''Angelica sinensis'' grows in cool high altitude mountains in East Asia. The yellowish brown root of th ...

'' (female ginseng), '' Cimicifuga heracleifolia'' and '' Ligusticum chuangxiong''. It is also found in the tea brewed from the European centaury (''

Centaurium erythraea ''Centaurium erythraea'' is a species of flowering plant in the gentian family known by the common names common centaury and European centaury. Description This is an erect biennial herb which reaches half a meter in height. It grows from a sma ...

''), a plant used as a medical herb in many parts of Europe.

In processed foods

Cooked

sweetcorn Sweet corn (''Zea mays'' convar. ''saccharata'' var. ''rugosa''), also called sugar corn and pole corn, is a variety of maize grown for human consumption with a high sugar content. Sweet corn is the result of a naturally occurring recessive muta ...

releases increased levels of ferulic acid. As plant sterol

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...

s, this compound is naturally found in rice bran oil, a popular cooking oil in several Asian countries. Ferulic acid

can be found in commercial

bread Bread is a staple food prepared from a dough of flour (usually wheat) and water, usually by baking. Throughout recorded history and around the world, it has been an important part of many cultures' diet. It is one of the oldest human-made f ...

s containing flaxseed.

Rye bread Rye bread is a type of bread made with various proportions of flour from rye grain. It can be light or dark in color, depending on the type of flour used and the addition of coloring agents, and is typically denser than bread made from wheat ...

contains

ferulic acid dehydrodimer Diferulic acids (also known as dehydrodiferulic acids) are organic compounds that have the general chemical formula C20H18O8, they are formed by dimerisation of ferulic acid. Curcumin and curcuminoids, though having a structure resembling diferul ...

Metabolism

Biosynthesis

Ferulic acid is biosynthesized in plants from caffeic acid by the action of the enzyme caffeate ''O''-methyltransferase. Ferulic acid, together with dihydroferulic acid, is a component of lignocellulose, 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

, and is also used for the synthesis of lignans.

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 ''Weizenbier'' and Belgian ''witbier''; other types include Lambic (made with wild ye ...

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 fungus microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have b ...

'' (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 ge ...

'' 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 radiobacter'' (more commonly known as ''Agrobacterium tumefaciens'') 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. Symptom ...

'', 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