What Are Aromatic Acids — Health Benefits and Food Sources
Introduction
Aromatic acids are organic compounds containing one or several carboxyl groups (-COOH) bonded to an aromatic ring, such as benzoic acid. Many aromatic acids possess various health-promoting properties, such as antioxidant, anti-inflammatory, and antimicrobial properties.
Aromatic acids include phenolic acids (such as gallic acid, protocatechuic acid, caffeic acid, ferulic acid, benzoic acid, and p-coumaric acid), p-aminobenzoic acid (PABA), salicylic acid, tannic acid, benzoic acid, cinnamic acid, gentisic acid, and more.
Different types of aromatic acids can be found in all types of foods (organ meat, meat, eggs, vegetables, fruits, and grains), herbs, tea, and coffee.
In this article, we’ll have a look at some aromatic acids and discuss their dietary sources and roles in our organisms.
Table of contents
Phenolic Acids
Phenolic acids are secondary plant metabolites with antioxidant, anti-inflammatory, immune regulating, antiallergic, antimicrobial, blood sugar lowering, antithrombotic, anticancer properties and more.
They are widespread in plant-based foods; thus, we consume them daily.
They contribute to the taste, color, and nutritional properties of foods. They can also be used as food additives to retain color and prolong the food’s shelf life.
The two main types include hydroxybenzoic acids and hydroxycinnamic acids.
Food Sources & Absorption
Phenolic acids are found in most types of foods. For example, from fruits, dark plum, cherry, red grape, apple, and citrus fruits have the highest phenolic acid content. From berries, rowanberry, raspberry, blueberry, and strawberry are the richest in phenolics, whereas from beverages - yerba mate, coffee, and tea.
The table below shows some of the phenolic acids’ content per 100g fresh weight (1).
| Ferulic acid (mg in 100g) | p-Coumaric acid (mg in 100g) | ||
| Common bean | 0.35 | Eggplant | 0.05mg |
| Soybean | 12 | Tomato | 0.13mg |
| Soybean sprout | 0.2 | Common beans | 0.32-0.68 |
| Cauliflower | 0.53 | Spinach | 0.13-2.87 |
| Eggplant | 0.22 | Coffeic acid (mg in 100g) | |
| Tomato | 0.27-6 | Eggplant | 0.38 |
| Spinach | 0.99-3.73 | Tomato | 0.45mg |
| Carrot | 1.2-2.8 | Carrot | 0.02mg |
| Broccoli | 4.1 | Potato | 1.62mg |
Free phenolic acids are released from food and beverage matrices in the stomach and are available for absorption. On the other hand, some phenolic acids (hydroxycinnamic acids) are in conjugated forms or bound to dietary fiber. They reach the colon to be metabolized by the colonic microbiota to increase their bioavailability and absorption.
Health Effects
Overall, phenolic acids improve health mainly due to their antioxidant and anti-inflammatory properties, decreasing the risk of cardiovascular disease and cancers, and may benefit in chronic inflammatory conditions.
Cardiovascular Health
Some phenolic acids, such as protocatechuic acid, show antiatherogenic effects by decreasing or increasing the expression of various genes associated with arterial inflammation. Others (p-coumaric acid, ferulic acid, p-hydroxybenzoic acid, vanillic acid, and hydroxycinnamic acid) are studied for their anti-obesity and cardioprotective effects through the reduction of total cholesterol, triglyceride, free fatty acid, and glucose levels in the blood.
Cancer
Some phenolics, such as caffeic and chlorogenic acids, may decrease the risk of stomach and colorectal cancers by protecting DNA integrity and regulating and inducing phase I and II enzymes, respectively. Others may reduce cell proliferation, promote programmed cell death, and block the activity of carcinogenic enzymes, thus showing anticancer effects.
Overall, most phenolic acids act at different points to block or cure various types of cancers.
Fatty Liver
Phenolic acid-rich extracts were also shown to decrease the risk of fatty liver by lessening cell fat deposition, fat accumulation, and liver fibrosis. They may also alleviate liver injury by decreasing oxidative stress and inflammation.
Neurological Health
Several phenolic acids, such as gallic, ferulic, and vanillic acids, are studied for their neuroprotective effects. In animal models, they may improve cognitive function in Alzheimer’s disease, showing therapeutic effects.
Diabetes
Phenolic acids may show beneficial effects on diabetes by influencing the function of insulin and glucose receptors. Chlorogenic and ferulic acids demonstrated similar effects to antidiabetic medications. Additionally, the best antidiabetic effect of phenolic acids may be due to blocking α-glucosidase and α-amylase enzymes, which are responsible for dietary carb conversion into glucose (1, 2, 3, 4, 5, 6).
P-aminobenzoic acid (PABA): Sources & Health Effects
PABA is also called aminobenzoic acid and sometimes vitamin Bx; however, it’s not a true vitamin; it’s a natural substance. PABA is needed for overall health and functioning and stimulates intestinal microbiota. PABA is found in whole grains, Brewer’s yeast, liver, molasses, mushrooms, and spinach.
PABA is known as a sunscreen and haircare component in cosmetics as it absorbs UV light. It was widely prescribed in the 1940s; however, its use has declined during the last decades due to its sensitizing effects and toxicity from overdose.
If used appropriately, PABA-containing products may decrease the risk of several types of skin cancer by reducing the amount of UV radiation.
PABA’s potassium salt, potassium aminobenzoate (PABA, Potaba), is used as a treatment option for Peyronie’s disease (PD), a disorder characterized by penile curvature that causes painful erections and scar tissue formation and may lead to erectile dysfunction. It has antifibrotic effects due to the production of increased oxygen uptake, which, in the end, prevents or leads to regression of tissue fibrosis (7, 8, 9, 10, 11).
Salicylic Acid: Sources & Health Effects
Salicylates, such as salicylic acid, are found in plants and function as hormonal mediators against pathogenic attacks and environmental stress. They are found in many foods, such as spices and herbs, fruits, vegetables, nuts, honey, and beverages.
The table below shows salicylic acid levels calculated per 100g serving (12).
| Foods | Salicylic acid levels per 100g |
| Nectarine | 0.39mg |
| Asparagus | 0.13mg |
| Cumin | 2.97mg |
| Black cumin | 2.50mg |
| Paprika | 2.82mg |
Several studies have shown that dietary salicylates promote health due to their antidiabetic, anticancer, and anti-inflammatory properties.
The anti-inflammatory properties of aspirin (aminosalicylic acid) are probably due to salicylic acid, as it has been shown to block the COX-2 inflammatory pathway in vitro.
Its high doses may increase the risk of respiratory alkalosis and gastrointestinal bleeding. Moreover, dietary salicylates may interact with medications like Aspirin, Ibuprofen, and Warfarin.
A greater intake of salicylates in vegetarians can result in high concentrations of salicylic acid in the blood and urine, comparable to a low dose of aspirin (75g) (12, 13, 14, 15).
Summary
Many aromatic acids possess various health-promoting properties, such as antioxidant, anti-inflammatory, and antimicrobial properties. Aromatic acids include phenolic acids, p-aminobenzoic acid (PABA), salicylic acid, tannic acid, benzoic acid, cinnamic acid, and gentisic acid.
Different types of aromatic acids can be found in all types of foods (organ meat, meat, eggs, vegetables, fruits, and grains), herbs, tea, and coffee.
Phenolic acids are among the most widespread aromatic acids, with antioxidant, anti-inflammatory, immune-regulating, antiallergic, antimicrobial, blood sugar-lowering, antithrombotic, and anticancer properties. Salicylic acid promotes health due to its antidiabetic, anticancer, and anti-inflammatory properties.
PABA is used for its antifibrotic effects as a treatment option for Peyronie’s disease, which causes painful erections and scar tissue formation and may lead to erectile dysfunction.
Sources
- https://pubmed.ncbi.nlm.nih.gov/32846511/
- https://link.springer.com/article/10.1007/s00394-019-01987-6
- https://link.springer.com/referenceworkentry/10.1007/978-3-642-22144-6_64
- https://www.mdpi.com/2072-6643/10/11/1615
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8433690/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6734135/
- https://www.cancer.gov/publications/dictionaries/cancer-terms/def/para-aminobenzoic-acid
- https://ec.europa.eu/health/ph_risk/committees/04_sccp/docs/sccp_o_058.pdf
- https://medlineplus.gov/ency/article/002518.htm
- https://hmdb.ca/metabolites/HMDB0001392
- https://emedicine.medscape.com/article/456574-overview
- https://www.researchgate.net/publication/50197171
- https://academic.oup.com/nutritionreviews/advance-article-abstract/doi/10.1093/nutrit/nuad136/7331240
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1770049/
- https://www.cambridge.org/core/services/aop-cambridge-core/content/view/482FFA77FF191993F68B54FBE09D414F/S0029665106000115a.pdf
