FERULIC ACID: OBTAINING, FUNCTIONS, APPLICATIONS - CHEMISTRY - 2024

The ferulic acid is a phenolic acid it found ubiquitously in the plant cell wall and thus is present in many foods consumed by humans.

Its abundance in plant tissues can vary from 5 grams per kilogram of tissue in wheat grain, up to 9 grams per kilogram in beet pulp or 50 grams per kilogram in corn kernels.

Ferulic acid chemical structure (Source: Calvero, via Wikimedia Commons)

It can be obtained from chemical synthesis or from natural sources of vegetable origin and has powerful antioxidant properties. This allows it to have multiple clinical pharmacological applications and also in the food and cosmetic industries.

It has been used since 1975 as a preservative and antimicrobial agent for food or vegetable oils for different purposes.

characteristics

Ferulic acid, also known as 4-hydroxy-3-methoxycinnamic acid, consists of a molecule of trans-cinnamic acid that has methoxy and hydroxy substituents at the 3 and 4 positions, respectively. This compound is the conjugated acid of ferulate.

Its molecular formula is C10H10O4 and it has a molecular weight of 194.18 g / mol. It is rarely found in its free form, as it is more commonly observed forming esters with polysaccharides of the cell wall such as arabinoxylans, pectin and xyloglycans, for example.

It can also be found complexing with proteins, suggesting that it can be used in the preparation of complex gels and other biomolecules.

Obtaining

Ferulic acid can be obtained by chemical synthesis or from natural compounds. By means of chemical synthesis, this can be obtained from condensation reactions between vanillin and malonic acid molecules and using piperidine as a catalyst agent.

With this method mixtures of cis and trans isomers of ferulic acid are obtained (with a high yield), but it has the disadvantage that the reactions take up to three weeks to complete.

Some researchers have improved this method of obtaining by using benzylamine as a catalytic agent and increasing the reaction temperature, increasing the yield and reducing the total synthesis time to less than 3 hours.

Obtained from natural sources

The main natural sources for obtaining ferulic acid are:

- Low molecular weight ferulic acid conjugates.

- Ferulic acid in the walls of plant cells.

- Tissue culture (beet, corn, etc.) or microbial fermentation.

The oil extracted from the bran of rice grains contains a high percentage of ferulol esters, making it an important natural source of ferulic acid.

There are scientific reports about obtaining ferulic acid from the cell wall of plants, the release of which is achieved using the enzymes feruloyl esterases, produced by some microorganisms (fungi, bacteria and yeasts).

Feruloyl esterases are enzymes belonging to a subclass of carboxylesterases and are capable of releasing ferulic acid molecules esterified to different types of substances such as, for example, methyl ferulate and certain feruloylated oligo and polysaccharides.

Although they are not commercially available, these enzymes have been extensively studied, since they represent a potential leap in terms of optimizing ferulic acid production, using fermentation technologies and genetic engineering.

Features and applications

Ferulic acid has many functions in various biological and industrial contexts. It is a powerful antioxidant, a metabolite in some types of plants, an anti-inflammatory agent, and a cardioprotective.

It is one of the most abundant phenolic acids in plant tissues, found primarily in seeds and leaves, in free form or conjugated with other biopolymers.

Its ability to form bonds with polysaccharides is industrially exploited to increase the viscosity and shape of gels composed of molecules such as pectin and some arabinoxylans.

Since the same is true for the reactions that take place between ferulic acid and many amino acids, it is used to improve the properties of protein-based "films".

In the food industry and other related

Since ferulic acid has a low percentage of toxicity, it has been approved for human consumption as an additive in different culinary preparations, where it functions mainly as a natural antioxidant in food, beverages and even cosmetics.

In North America, ferulic acid is widely used in the preparation of essences and natural extracts of coffee, vanilla, herbs, spices and other plants of commercial interest.

In the particular case of vanillin (vanilla), which is an aromatic compound widely used in gastronomy and cosmetology, various bioconversion experiments have been carried out from natural sources (other than orchid pods) such as lignin, amino acids aromatics and ferulic acid.

Chemical structure of vanillin (Source: Edgar181 via Wikimedia Commons)

Certain species of fungi, yeasts, and bacteria have the ability to secrete enzymes that can convert ferulic acid into vanillin, either by decarboxylation, reduction, or through the formation of a coniferyl alcohol.

In pharmacology and medicine

The addition of ferulic acid and curcumin to meals is considered to be a nutritional technique to reduce oxidative damage and amyloid pathology related to Alzheimer's disease.

In addition, several studies show that ferulic acid is an excellent antioxidant, since it neutralizes free radicals and increases the activity of the enzymes responsible for the inhibition of free radical-producing enzymes in the body.

The activity of ferulic acid in reducing the levels of cholesterol and low-density lipoproteins in the blood plasma has also been proven, this in rodents fed diets rich in coconut oil and cholesterol.

Chinese medicine also exploits various aspects of ferulic acid; such is the case of the use of herbs rich in this for the treatment of common conditions such as thrombosis and arteriosclerosis.

Ferulic acid has antimicrobial and anti-inflammatory activity, as it prevents the growth and reproduction of viruses such as influenza, the AIDS virus and other syncytial viruses of the respiratory tract, which has been exploited for millennia in Japanese oriental medicine.

References

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4. National Center for Biotechnology Information. PubChem Database. Ferulic acid, CID = 445858, www.pubchem.ncbi.nlm.nih.gov/compound/Ferulic-acid (accessed on Oct. 17, 2019)
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