Ferulic acid is ubiquitous in the plant kingdom, including a number of vegetable sources. It occurs in particularly high concentrations in
popcorn and
bamboo shoots. It is a major metabolite of
chlorogenic acids in humans along with
caffeic and
isoferulic acid, and is absorbed in the
small intestine, whereas other metabolites such as
dihydroferulic acid,
feruloylglycine, and dihydroferulic acid are produced from chlorogenic acid in the
large intestine by the action of
gut flora. In cereals, ferulic acid is localized in the
bran – the hard outer layer of grain. In
wheat, 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 has been found in
flaxseed (). It is also found in
barley grain.
Asterid eudicot plants can also produce ferulic acid. The tea brewed from the leaves of
yacón (
Smallanthus sonchifolius), a plant traditionally grown in the northern and central
Andes, contains quantities of ferulic acid. In
legumes, the white bean variety
navy bean is the richest source of ferulic acid among the
common bean (
Phaseolus vulgaris) varieties. It is also found in
horse grams (
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 polysaccharides, allowing it to be released and absorbed in the small intestine.
In processed foods Cooking
sweetcorn releases increased levels of ferulic acid. As
plant sterol esters, this compound is naturally found in
rice bran oil, a popular cooking oil in several Asian countries. Ferulic acid
glucoside can be found in commercial
breads containing
flaxseed.
Rye bread contains
ferulic acid dehydrodimers. == Metabolism ==