The Sunlight Experiment

Compound Monograph

Caffeic acid

Caffeic acid — a widely distributed hydroxycinnamic (phenolic) acid best characterised as an antioxidant, with reported anti-inflammatory, gastroprotective and antidepressant-like activity.

Work in progress

Classification

Caffeic acid is a hydroxycinnamic acid (phenolic acid), part of the phenolics class. Antioxidant compounds built around one or more phenol rings — the flavonoids, tannins, phenolic acids, coumarins, and pigments behind much of a plant's protective chemistry.

Phenolics Phenolic Acids

Where Does It Come From? (25)

Caffeic acid is a naturally occurring hydroxycinnamic acid (phenolic acid), found in Globe Artichoke, Coffee, Guarana and 22 other sources. It is well tolerated orally (low toxicity).

Amaranth Amaranthus blitum Calamus Acorus calamus Chrysanthemum Chrysanthemum morifolium Clove Syzygium aromaticum Coffee Coffea arabica Cornflower Centaurea cyanus Couchgrass Elytrigia repens Globe Artichoke Cynara scolymus Goldenrod Solidago virgaurea Guarana Paullinia cupana Hawthorn Crataegus oxyacantha Horsetail Equisetum arvense Hyssop Hyssopus officinalis Jasmine Jasminum officinale Marshmallow Althaea officinalis Most fruits, vegetables and coffee Olive Leaf Olea europaea Pau D'Arco Tabebuia impetiginosa Sage Samambaia Polypodium leucotomos Sarsaparilla Smilax spp. Stevia Stevia rebaudiana Stinging Nettle Urtica dioica Thyme Thymus vulgaris Yerba Maté Ilex paraguariensis

Research & Evidence

Caffeic acid is a hydroxycinnamic acid — a phenolic acid found throughout the plant kingdom and present, often as its esters, in many of the herbs in this database. Despite the similarity in name it is unrelated to caffeine. Its recurring theme across the source monographs is antioxidant activity, with several plant-specific findings layered on top.

  • Antidepressant-like / neuroactive — in Tabebuia avellanedae (pau d’arco), the caffeic acid content was found to produce both antioxidant and antidepressant-like effects, reported to act through modulation of NMDA (N-methyl-D-aspartate) receptors 1Reference 1Freitas et al. · 2013AnimalNMDA Receptors and the L-Arginine–Nitric Oxide–Cyclic Guanosine Monophosphate Pathway Are Implicated in the Antidepressant-Like Action of the Ethanolic Extract from Tabebuia avellanedae in Mice.
  • Gastroprotective — guarana’s protective effect against gastric lesions is attributed to its polyphenol content, specifically caffeic acid, gallic acid and tannic acid 2Reference 2Basile et al. · 2005Antibacterial and antioxidant activities of ethanol extract from Paullinia cupana Mart.
  • Photoprotection / antioxidant — in Polypodium leucotomos (samambaia), caffeic acid is named among the phenolic constituents responsible for the plant’s antioxidant and photoprotective effects 3,4Reference 3Gombau L et al. · 2006In vitroPolypodium leucotomos extract: antioxidant activity and dispositionReference 4Garcia F et al. · 2006Phenolic components and antioxidant activity of Fernblock, an aqueous extract of the aerial parts of the fern Polypodium leucotomos.
  • Antioxidant in artichoke — much of globe artichoke’s antioxidant capacity is attributed to its polyphenols, particularly chlorogenic acid, di-caffeoylquinic acids and caffeic acid, concentrated in the flowering bracts 5Reference 5Gabriella Sonnante et al. · 2010Novel Hydroxycinnamoyl-Coenzyme A Quinate Transferase Genes from Artichoke Are Involved in the Synthesis of Chlorogenic Acid.
  • Other sources — caffeic acid is also documented in coffee (in modest amounts, with its own antioxidant, immunomodulatory and anti-inflammatory profile), and as a constituent of yerba maté, stinging nettle, marshmallow, sarsaparilla and stevia, where it contributes to each plant’s phenolic-acid fraction.

Toxicity & Safety

Caffeic acid is a common dietary phenolic acid and is well tolerated; none of the source herb monographs flag it as toxic. The herbs that contain it are generally regarded as safe at customary doses, and any cautions (for example those attached to pau d’arco or yerba maté) belong to the whole herb rather than to caffeic acid specifically. The source material does not describe an isolated-compound overdose or interaction profile for caffeic acid.

References

  1. Freitas, A. E., Moretti, M., Budni, J., Balen, G. O., Fernandes, S. C., Veronezi, P. O., … & Rodrigues, A. L. S. (2013). NMDA Receptors and the L-Arginine–Nitric Oxide–Cyclic Guanosine Monophosphate Pathway Are Implicated in the Antidepressant-Like Action of the Ethanolic Extract from Tabebuia avellanedae in Mice. Journal of Medicinal Food, 16(11), 1030-1038.
  2. Basile, A., Ferrara, L., Del Pezzo, M., Mele, G., Sorbo, S., Bassi, P., & Montesano, D. (2005). Antibacterial and antioxidant activities of ethanol extract from Paullinia cupana Mart. Journal of Ethnopharmacology, 102(1), 32-36.
  3. Gombau L, García F, Lahoz A, et al. (2006). Polypodium leucotomos extract: antioxidant activity and disposition. Toxicology in Vitro, 20:464–471.
  4. Garcia F, Pivel JP, Guerrero A, et al. (2006). Phenolic components and antioxidant activity of Fernblock, an aqueous extract of the aerial parts of the fern Polypodium leucotomos. Methods and Findings in Experimental and Clinical Pharmacology, 28:157–160.
  5. Gabriella Sonnante, Rosalinda D’Amore, Emanuela Blanco, Ciro L. Pierri, Monica De Palma, Jie Luo, Marina Tucci, and Cathie Martin. (2010). Novel Hydroxycinnamoyl-Coenzyme A Quinate Transferase Genes from Artichoke Are Involved in the Synthesis of Chlorogenic Acid. Plant Physiology, 153, 1224–1238.