Sinapic Acid

• Antioxidant protection
• Anti-inflammatory
• Neuroprotection
• Hepatoprotection

• Cardiovascular support
• Blood glucose regulation
• Anti-cancer properties
• Antimicrobial activity
• Skin protection
• Detoxification support

Sinapic acid exerts its diverse biological effects through multiple mechanisms at the molecular level. As a potent antioxidant, sinapic acid effectively neutralizes free radicals through direct scavenging of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Its unique chemical structure, featuring a phenolic nucleus with two methoxy groups and an extended side chain with a conjugated double bond, allows it to form a resonance-stabilized phenoxy radical that accounts for its potent antioxidant activity. The presence of the two methoxy groups in positions 3 and 5 of the aromatic ring enhances its electron-donating capacity, making it particularly effective at neutralizing free radicals.

Sinapic acid also enhances the body’s endogenous antioxidant defenses by activating the Nrf2 (Nuclear factor erythroid 2-related factor 2) signaling pathway, which leads to increased expression of antioxidant enzymes such as glutathione S-transferase (GST), NAD(P)H:quinone oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1), and γ-glutamylcysteine synthetase (γ-GCS). This activation occurs through sinapic acid’s ability to modify Keap1 (Kelch-like ECH-associated protein 1), the cytosolic repressor of Nrf2, allowing Nrf2 to translocate to the nucleus and bind to antioxidant response elements (ARE) in the promoter regions of target genes. Sinapic acid exhibits strong anti-inflammatory properties by inhibiting the NF-κB (nuclear factor kappa B) signaling pathway, a master regulator of inflammatory responses. It suppresses the phosphorylation and degradation of IκB (inhibitor of kappa B), preventing the nuclear translocation of NF-κB and subsequent expression of pro-inflammatory genes.

Sinapic acid also inhibits the production of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). Additionally, it suppresses the activity of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), thereby reducing the production of prostaglandins and nitric oxide that contribute to inflammation. In the liver, sinapic acid provides hepatoprotection through multiple mechanisms. It enhances the activity of phase II detoxification enzymes, facilitating the elimination of toxins and reducing oxidative stress in hepatocytes.

Sinapic acid also inhibits lipid peroxidation in liver cell membranes and prevents mitochondrial dysfunction, which are key factors in various liver diseases. Furthermore, it modulates the expression of genes involved in lipid metabolism, reducing hepatic steatosis and improving overall liver function. For neuroprotection, sinapic acid crosses the blood-brain barrier and exerts multiple beneficial effects on neuronal cells. It reduces oxidative stress in the brain by scavenging free radicals and enhancing antioxidant enzyme activities.

Sinapic acid inhibits acetylcholinesterase (AChE) activity, increasing acetylcholine levels and potentially improving cognitive function. It also suppresses neuroinflammation by inhibiting microglial activation and reducing the production of pro-inflammatory cytokines in the brain. Additionally, sinapic acid protects against amyloid-β-induced neurotoxicity and tau hyperphosphorylation, which are key pathological features of Alzheimer’s disease. In the cardiovascular system, sinapic acid improves endothelial function by enhancing nitric oxide (NO) production through increased expression and activity of endothelial nitric oxide synthase (eNOS).

It also reduces lipid peroxidation in blood vessels and inhibits platelet aggregation, contributing to its cardioprotective effects. Sinapic acid positively influences lipid metabolism by inhibiting HMG-CoA reductase, the rate-limiting enzyme in cholesterol synthesis, and by promoting cholesterol efflux from cells. For metabolic health, sinapic acid enhances insulin sensitivity by activating the insulin receptor substrate-1 (IRS-1)/phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, which increases glucose uptake in tissues. It also inhibits key enzymes involved in carbohydrate metabolism, such as α-amylase and α-glucosidase, slowing glucose absorption and reducing postprandial glucose spikes.

Sinapic acid demonstrates anticancer potential through multiple mechanisms, including cell cycle arrest, induction of apoptosis in cancer cells, inhibition of angiogenesis, and modulation of various signaling pathways involved in cell proliferation and survival. It also inhibits matrix metalloproteinases (MMPs), which are involved in tumor invasion and metastasis. For skin health, sinapic acid provides photoprotection by absorbing UV radiation and neutralizing UV-induced free radicals. It also inhibits matrix metalloproteinases that degrade collagen and elastin, thereby helping to maintain skin structural integrity and potentially reducing signs of aging.

The optimal dosage range for sinapic acid supplements is not well-established in humans due to limited clinical trials. Based on preclinical studies and the limited human research available, dosages typically range from 20-200 mg per day. For general antioxidant support and preventive benefits, 20-50 mg daily is commonly suggested. Higher doses (100-200 mg) have been used in animal studies targeting specific health conditions, but human equivalent doses require further validation.

Sinapic acid has moderate oral bioavailability, estimated at approximately 15-25% in humans based on limited studies. The absorption occurs primarily in the small intestine through both passive diffusion and active transport mechanisms involving monocarboxylic acid transporters (MCTs). Free sinapic acid is absorbed more readily than its bound forms found in foods. In plants, sinapic acid often exists as esters (particularly sinapine, the choline ester of sinapic acid), which must be hydrolyzed by intestinal esterases before absorption.

Some sinapic acid may also reach the colon, where it can be metabolized by gut microbiota, potentially producing bioactive metabolites with different properties than the parent compound.

Liposomal encapsulation: Can increase bioavailability by 2-3 times by protecting sinapic acid from degradation and enhancing cellular uptake, Nanoparticle formulations: May increase bioavailability by up to 3-4 times through improved solubility and cellular penetration, Co-administration with piperine (black pepper extract): Can inhibit glucuronidation and increase bioavailability by approximately 30-50%, Phytosomal complexes: Binding sinapic acid with phospholipids can enhance absorption by 2-3 times, Lipophilic esterification: Converting sinapic acid to alkyl esters (particularly medium to long-chain esters like hexyl sinapate or palmitoyl sinapate) can significantly improve lipophilicity and membrane permeability, Taking with a small amount of healthy fats: May enhance absorption of sinapic acid, Consuming with other antioxidants: Synergistic effects have been observed when combined with other antioxidants like vitamin C, vitamin E, or other phenolic compounds, Microemulsion delivery systems: Can improve solubility and stability, potentially enhancing bioavailability

For optimal absorption, sinapic acid supplements are best taken on an empty stomach, 30 minutes before meals or 2 hours after meals. However, if gastrointestinal discomfort occurs, it can be taken with food, preferably with a small amount of healthy fat to enhance absorption. For liver protective effects, taking sinapic acid with meals may be beneficial as it can help neutralize dietary oxidants and support detoxification processes. For antioxidant and anti-inflammatory effects, consistent daily dosing is more important than specific timing.

When used for neuroprotection, some research suggests that morning administration may be preferable, though evidence is limited. For blood glucose management, taking sinapic acid 15-30 minutes before meals may help reduce post-prandial glucose spikes. When used for photoprotection, oral supplements should be taken consistently for at least 4-6 weeks to build up protective effects, while topical applications are most effective when applied in the morning under sunscreen. The half-life of sinapic acid in the body is relatively short (estimated at 1-3 hours), so divided doses throughout the day may provide more consistent benefits for certain conditions.

• Gastrointestinal discomfort (mild nausea, stomach upset)
• Headache (rare)
• Skin irritation (with topical applications in sensitive individuals)
• Allergic reactions (rare, more common in individuals with allergies to plants containing sinapic acid)
• Drowsiness (reported in some individuals at higher doses)
• Temporary increase in liver enzymes (rare, at very high doses)

• Known hypersensitivity or allergy to sinapic acid or plants high in sinapic acid (such as mustard, rapeseed, or certain grains)
• Pregnancy and breastfeeding (due to insufficient safety data)
• Bleeding disorders (theoretical concern due to potential mild antiplatelet effects)
• Scheduled surgery (discontinue 2 weeks before due to potential antiplatelet effects)
• Hormone-sensitive conditions (theoretical concern due to potential weak estrogenic effects)
• Severe liver or kidney disease (use with caution due to limited research)

• Anticoagulant and antiplatelet medications (may enhance blood-thinning effects)
• Antihypertensive drugs (may enhance blood pressure-lowering effects)
• Antidiabetic medications (may enhance blood glucose-lowering effects)
• Hepatotoxic drugs (theoretical concern for additive effects at very high doses)
• Drugs metabolized by cytochrome P450 enzymes (potential for mild interactions)
• Acetylcholinesterase inhibitors (may have additive effects due to sinapic acid’s mild AChE inhibitory activity)
• Sedative medications (potential additive effects with higher doses of sinapic acid)

No official upper limit has been established. Most preclinical studies have used doses equivalent to 200-300 mg daily in humans without significant adverse effects. However, for long-term use, doses above 200 mg daily are not recommended without medical supervision due to limited long-term safety data. For topical applications, concentrations up to 2% have been used safely in cosmetic formulations, though most products use 0.5-1% concentration.

In the United States, sinapic acid is not approved as a drug but is generally recognized as safe (GRAS) as a food component naturally present in many common foods. As a dietary supplement ingredient, it falls under the Dietary Supplement Health and Education Act (DSHEA) of 1994, which means manufacturers cannot make specific disease treatment claims but can make structure/function claims about its effects on normal body functions. For cosmetic use, sinapic acid is approved as a skin conditioning agent and antioxidant. The FDA does not require pre-market approval for dietary supplements containing sinapic acid, but manufacturers are responsible for ensuring safety and accurate labeling.

Sinapic acid is less commonly found as a standalone supplement compared to other phenolic acids like ferulic acid, and is more often included as part of complex plant extracts or formulations.

Eu: In the European Union, sinapic acid is recognized as a natural food component and is permitted in food supplements under the Food Supplements Directive (2002/46/EC). It must comply with general food safety regulations. Novel food authorization may be required for certain applications or extraction methods. For cosmetic use, it is listed in the European Inventory of Cosmetic Ingredients as an antioxidant and skin conditioning agent. The European Food Safety Authority (EFSA) has not issued specific health claims for sinapic acid.

Canada: Health Canada permits sinapic acid in natural health products (NHPs) with appropriate safety data. It is listed in the Natural Health Products Ingredients Database (NHPID) with antioxidant and skin conditioning roles. Product license applications must include quality, safety, and efficacy information. As with the US, it is more commonly found as part of plant extracts rather than as an isolated compound.

Australia: The Therapeutic Goods Administration (TGA) permits sinapic acid in listed complementary medicines. It is included in the Australian Inventory of Chemical Substances (AICS) and permitted for use in cosmetics and personal care products. Specific therapeutic claims require higher levels of evidence and registration as a registered medicine.

Japan: In Japan, sinapic acid is approved as a food component and is also permitted in quasi-drug formulations for skin conditioning and antioxidant properties. The Ministry of Health, Labour and Welfare regulates its use in various applications.

China: The National Medical Products Administration (NMPA) permits sinapic acid in both cosmetic formulations and health food products with appropriate registration. Traditional Chinese Medicine formulations containing sinapic acid-rich herbs have separate regulatory pathways.

India: The Food Safety and Standards Authority of India (FSSAI) recognizes sinapic acid as a natural food component. For use in Ayurvedic and traditional formulations, it falls under AYUSH regulations when present in natural herbal extracts.

Medium to high

For standard sinapic acid supplements (20-50 mg daily): $0.40-$1.20 per day. For higher potency supplements (100-200 mg daily): $0.90-$3.00 per day. Enhanced delivery forms (liposomal, phytosomal): $1.80-$4.50 per day. Topical formulations: $1.20-$6.00 per daily application, depending on concentration and additional ingredients. Sinapic acid esters (particularly lipophilic esters): $1.50-$4.00 per day.

Sinapic acid offers moderate value for its cost, particularly when considering its multiple health benefits. However, it is generally more expensive than more common phenolic acids like ferulic acid, primarily due to lower commercial production volumes and more limited market presence. For general antioxidant support, more cost-effective alternatives exist (such as vitamin C or ferulic acid), but sinapic acid’s unique mechanisms and potential specific benefits for liver and neurological health may justify the higher cost for certain health goals. The best value is typically found in products that contain sinapic acid as part of a broader spectrum of phenolic compounds from natural extracts, such as those from mustard seed, rapeseed, or whole grain sources.

These provide not only sinapic acid but also complementary compounds that may work synergistically. Enhanced delivery systems significantly increase cost but may provide better value through improved bioavailability, especially for individuals with absorption issues or those seeking specific therapeutic effects. For skin health and photoprotection, topical formulations that combine sinapic acid with other antioxidants like vitamins C and E offer good value despite higher upfront costs, as they provide scientifically validated benefits that may reduce the need for more expensive cosmetic procedures. Consumers should be cautious of very low-priced products claiming to contain pure sinapic acid, which may contain lower purity or potency than claimed.

Similarly, extremely high-priced products often reflect marketing rather than superior quality. For most health applications, moderate price point products from reputable manufacturers offer the best balance of quality and value. Food sources of sinapic acid (such as mustard seeds, whole grains, and certain fruits and vegetables) provide the most cost-effective way to obtain this compound, though in lower concentrations than supplements. Incorporating these foods into the diet is generally the most economical approach to obtaining the benefits of sinapic acid.

Pure sinapic acid powder typically has a shelf life of 1-2 years

when properly stored. Capsules and tablets generally have a shelf life of 1-2 years. Liquid formulations and topical products containing sinapic acid usually have shorter shelf lives of 6-12 months after opening due to increased vulnerability to oxidation. Sinapic acid esters, particularly lipophilic esters like palmitoyl sinapate, generally have improved stability compared to free sinapic acid, with shelf lives of 2-3 years

when properly stored.

Store in a cool, dry place away from direct sunlight and heat sources. Ideal temperature range is 15-25°C (59-77°F). Keep container tightly closed when not in use to prevent moisture absorption. For topical products, refrigeration after opening may extend stability.

Avoid storing near strong-smelling substances as sinapic acid may absorb odors. For powder forms, use a desiccant in the container if the original packaging doesn’t include one. Sinapic acid is more stable under slightly acidic conditions (pH 5-6) than under neutral or basic conditions, so formulations with appropriate pH buffering may have extended stability.

Exposure to light (especially UV light) accelerates oxidation, High temperatures (above 30°C/86°F) significantly reduce stability, Moisture and humidity promote hydrolysis and degradation, Alkaline pH conditions (pH > 7) increase degradation rate, Presence of metal ions (particularly iron and copper) catalyzes oxidation, Oxygen exposure leads to oxidative degradation, Microbial contamination can occur in liquid formulations without proper preservatives, Repeated freeze-thaw cycles accelerate degradation, For topical formulations, incompatible ingredients may reduce stability, Enzymatic degradation can occur in some formulations, Sinapic acid may undergo isomerization from the trans to cis form under certain conditions, particularly when exposed to UV light, which can reduce its biological activity

Synthesis Methods

Natural Sources

Quality Considerations

Sinapic acid has a rich history of indirect traditional use, primarily through the consumption of plants and foods that naturally contain high levels of this compound. While sinapic acid itself was not specifically identified or isolated until the early 20th century, many traditional medicinal plants rich in this compound have been used for centuries across different cultures. In traditional European herbal medicine, mustard seeds and preparations, which are particularly rich in sinapic acid (often in the form of sinapine, its choline ester), were used for their warming properties, as rubefacients (substances that increase blood flow to the skin), and for respiratory conditions. Mustard plasters were a common traditional remedy for chest congestion, coughs, and muscle pain.

In Traditional Chinese Medicine (TCM), various Brassica vegetables and seeds containing sinapic acid were incorporated into formulations for their warming properties and to support digestive health. These plants were often used to dispel ‘cold’ and ‘damp’ conditions according to TCM principles. In Ayurvedic medicine, mustard seeds and oil (sarson) have been used for thousands of years for their warming, stimulating, and detoxifying properties. They were applied externally for muscle pain and internally for digestive and respiratory conditions.

In traditional Nordic and Eastern European cuisines, rye bread and fermented foods rich in sinapic acid were dietary staples, valued not only for their nutritional properties but also for their preservative effects and health benefits. The fermentation process may have enhanced the bioavailability of sinapic acid and other phenolic compounds. Native American healing traditions utilized various plants containing sinapic acid, including certain berries and wild mustard relatives, for their medicinal properties. These were often used for pain relief, wound healing, and respiratory conditions.

The modern scientific interest in sinapic acid began in the early 20th century when it was first isolated and characterized, but significant research into its health benefits only gained momentum in the 1980s and 1990s with the growing interest in plant phenolics and antioxidants. Initially, sinapic acid was primarily studied for its role as a natural antioxidant in food preservation. Its application in nutritional supplements is relatively recent, emerging in the last 10-15 years as research on its health benefits has expanded. In contemporary food science, sinapic acid and its derivatives (particularly sinapine) have been recognized as important bioactive compounds in mustard, rapeseed, and various whole grains.

The bitter taste associated with some of these foods is partly attributed to sinapic acid compounds, and food processing techniques have been developed to either reduce this bitterness or enhance the extraction and bioavailability of these beneficial compounds. Today, sinapic acid is recognized as a multifunctional compound with applications spanning from food preservation to cosmetic formulations and health supplements, representing a bridge between traditional plant-based healing and modern evidence-based approaches to health and wellness.

No comprehensive meta-analyses specifically on sinapic acid interventions have been published to date. Most evidence comes from individual preclinical studies, in vitro research, and limited human trials., Several systematic reviews have included sinapic acid as part of broader analyses of phenolic compounds and their health effects, particularly in the context of dietary antioxidants.

Investigation of sinapic acid derivatives for neuroprotective effects in models of Alzheimer’s disease, Evaluation of sinapic acid-rich extracts for hepatoprotective effects against drug-induced liver injury, Sinapic acid alkyl esters as novel food preservatives and antioxidants, Topical formulations containing sinapic acid for photoprotection and skin aging, Sinapic acid as a complementary approach for managing metabolic syndrome components