trans-caffeic acid

Overview

Trans-caffeic acid (systematic name: (E)-3-(3,4-dihydroxyphenyl)acrylic acid), also referred to simply as caffeic acid (CA), is a naturally occurring hydroxycinnamic acid and polyphenolic compound widely distributed across the plant kingdom. It is the predominant geometric isomer of caffeic acid encountered in biological systems and is found abundantly in medicinal herbs, vegetables, fruits, and traditional botanical preparations. Structurally, it features a catechol ring system conjugated to an acrylic acid side chain in the trans configuration, a geometry that confers both chemical stability and potent radical-scavenging capacity. Trans-caffeic acid frequently occurs in esterified forms — most notably as (E)-chlorogenic acid (the 5-O-caffeoylquinoate ester) — or in combination with other Phenolic Acids such as ferulic acid, gallic acid, and luteolin within complex plant matrices.

Biologically, trans-caffeic acid exhibits a broad spectrum of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial, hepatoprotective, and neuroprotective effects. It is recognized as a modulator of multiple cellular signaling cascades, and its capacity to penetrate the blood-brain barrier has attracted growing interest in the context of neurodegeneration and brain aging. The compound also interacts with metabolic enzymes such as alpha-glucosidase and amylase alpha 1C, positioning it as a candidate for managing metabolic disorders, while its influence on pathways including JAK2/STAT3 signaling has implications for cardiac and oncological research.

Focus of Latest Publications

Recent scientific literature has consistently identified trans-caffeic acid as a key bioactive constituent across a diverse range of plant-based research contexts, from quality-control studies of traditional medicinal herbs to functional food packaging and multi-organ pharmacological investigations.

A 2026 study published in Spectrochimica Acta Part A employed near-infrared spectroscopy combined with chemometrics to simultaneously quantify multiple phytochemical markers — including caffeic acid, chicoric acid, and luteolin — in Taraxaci Herba (dandelion herb, TH) and discriminate samples by geographical origin. The inclusion of caffeic acid alongside luteolin as a target analyte underlines its value as a chemical authenticity marker in botanical quality control. Complementing this, a separate investigation in Ultrasonics Sonochemistry optimized the extraction of bioactive compounds from dandelion (Taraxacum officinale) using response surface methodology, identifying caffeic acid alongside chlorogenic acid, quercetin, apigenin, luteolin-7-O-glycoside, p-coumaric acid, ferulic acid, cichoric acid, isoetin, and caftaric acid under optimized ultrasound-assisted extraction conditions.

In the domain of food science and preservation, a 2026 study in the International Journal of Biological Macromolecules leveraged trans-caffeic acid's metal-chelating and phenolic coordination chemistry. By incorporating caffeic acid together with zinc oxide (ZnO) into potato protein/gelatin composite films via metal-phenolic coordination, researchers engineered multifunctional food packaging materials with enhanced antioxidant, antimicrobial, and freshness-monitoring properties, demonstrating caffeic acid's utility beyond pure pharmacological contexts.

In the realm of neuroprotection and brain aging, a 2026 Biomedical Chromatography study using UPLC-MS, bioinformatics, and in vivo approaches investigated the anti-brain aging effects of Polygalae Radix and its processed products. Caffeic acid was among thirteen brain-penetrating components identified — alongside tenuifolin, chlorogenic acid, and 3,4,5-trimethoxycinnamic acid — underscoring its ability to cross the blood-brain barrier and contribute to central nervous system-relevant pharmacological effects.

The antidiabetic and renoprotective potential of plant-derived phenolics including caffeic acid was explored in a 2026 Chemistry & Biodiversity study examining fermented Bambusa nutans (bamboo shoot) extracts in a streptozotocin-induced mouse model of renal injury. Fermentation markedly enhanced caffeic acid concentrations (up to 28.36% increase), alongside quercetin, chlorogenic acid, gallic acid, and salicylic acid, with the enriched extract demonstrating protective effects against renal biochemical and histopathological alterations. Enzyme targets relevant to this context include alpha-glucosidase and amylase alpha 1C, which are known to be modulated by hydroxycinnamic acids such as trans-caffeic acid.

In cardiovascular pharmacology, a 2026 Biomedical Chromatography study applied UPLC-Q-TOF/MS-driven systems pharmacology, integrating serum and tissue distribution profiling, molecular docking, and single-cell RNA sequencing (scRNA-seq) to analyze the Dengzhan Shengmai Capsule in the context of heart failure. Caffeic acid was identified among the critical bioactive compounds alongside ferulic acid, quercetin-3-O-glucuronide, hyperoside, scutellarin, schizandrin A, and schizandrin B, with network pharmacology implicating pathways such as the JAK2/STAT3 signaling axis and effectors including L-lactate dehydrogenase and DENR.

Phytochemical profiling of lesser-studied medicinal plants has also highlighted trans-caffeic acid's ubiquity. A 2026 ChemistryOpen multiassay study of Chaerophyllum aksekiense organ extracts using LC-ESI-MS/MS revealed distinct organ-specific distribution of caffeic acid alongside hyperoside, gallic acid, and hydroxybenzoic acids, correlating its presence with antioxidant capacity and enzyme inhibitory activity.

Key Publications

• NEWJun Unlocking the Role of Chia (Salvia hispanica L.) Seed Phenolic Metabolites in Postprandial Glucose Modulation: in vitro, in vivo, and Antioxidant Evidence Supported by Molecular Docking. (Plant foods for human nutrition (Dordrecht, Netherlands), 2026, PMID 42313210): "The methanolic extract (MESh) exhibited the highest phenolic content and antioxidant activity, a phenolic profile dominated by rosmarinic acid, caffeic acid, and their hexosides, and the strongest antihyperglycemic effect, producing a glycemic curve comparable to acarbose."
• Jun Caffeic Acid Ameliorates l-Methionine-Induced Hyperhomocysteinemia, Leading to Decreased Adult Neurogenesis and Oxidative Stress Status in Adult Rats. (ACS chemical neuroscience, 2026, PMID 42216877): "Caffeic acid (CA) possesses antioxidant properties that reduce brain oxidative damage and promote neurogenesis."
• Jun Formation and Characterization of (-)-Epigallocatechin Gallate-Caffeic Acid Adduct and Their Quantitative Changes during the Processing of Green Tea. (Journal of agricultural and food chemistry, 2026, PMID 42246632): "two novel EGCG derivatives (EGCG-CAs) formed by conjugating caffeic acid (CA) were identified in green tea."
• Jun Simultaneous multi-component quantification and geographical origin discrimination of Taraxaci Herba using near-infrared spectroscopy combined with chemometrics. (Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 2026, PMID 41740399): "the content of chicoric acid (CHA), caffeic acid (CA), and luteolin (LUT) in TH were determined by high-performance liquid chromatography (HPLC)"
• Jun From Chemical Discrepancy to Mechanistic Insight: UPLC-MS, Bioinformatics, and In Vivo Studies on the Anti-Brain Aging Effects of Polygalae Radix and Its Processed Products. (Biomedical chromatography : BMC, 2026, PMID 42011008): "Thirteen brain-penetrating components were identified, including tenuifolin, 3,4,5-trimethoxycinnamic acid, chlorogenic acid, liquiritigenin, and caffeic acid."
• Jun Metal-phenolic interaction engineered potato protein/gelatin multifunctional films for food preservation and freshness monitoring. (International journal of biological macromolecules, 2026, PMID 42119876): "...and incorporating zinc oxide (ZnO) and caffeic acid (CA) through metal-phenolic coordination."
• Jun A comprehensive insight into optimized ultrasound-assisted extraction of bioactive compounds and antioxidant activities from dandelion (Taraxacum officinale) plant extract using response surface methodology. (Ultrasonics sonochemistry, 2026, PMID 42068787): "Under optimized conditions major bioactive compounds identified and quantified were chlorogenic acid, quercetin, apigenin, luteolin-7-O-glycoside, luteolin, p-coumaric acid, caffeic acid, ferulic acid, cichoric acid, isoetin, and caftaric acid."
• Jun Effect of Processing on the Protective Role of Bambusa nutans Wall. ex Munro Extract Against Streptozotocin-Induced Renal Biochemical and Histopathological Alterations in LACA Mice. (Chemistry & biodiversity, 2026, PMID 42216852): "Fermentation significantly enhanced bioactive components, including caffeic acid (up to 28.36%), quercetin (28.39%), chlorogenic acid (37.50%), salicylic acid (59.24%), coumaric acid (61.90%), gallic acid (66.67%)."
• May UPLC-Q-TOF-MS-Driven Systems Pharmacology Analysis of Dengzhan Shengmai Capsule Against Heart Failure: Integrating Serum/Tissue Distribution, Molecular Docking, and scRNA-seq Evidence. (Biomedical chromatography : BMC, 2026, PMID 41952432): "Critical bioactive compounds include caffeic acid, ferulic acid, quercetin-3-O-glucuronide, hyperoside, scutellarin, schizandrin A, and schizandrin B."
• May Organ-Specific Phytochemical Composition and Bioactivity Profiling of Chaerophyllum aksekiense: A Multiassay Antioxidant, Enzyme Inhibition, and Correlation-Based Evaluation. (ChemistryOpen, 2026, PMID 42051056): "LC-ESI-MS/MS analysis revealed distinct distribution patterns of key compounds, including hyperoside, gallic acid, caffeic acid, and hydroxybenzoic acids."