Sinapic acid

Pharmacology & Research

Sinapic acid is a hydroxycinnamic acid — the 3,5-dimethoxy analogue of ferulic acid and caffeic acid — abundant in the Brassicaceae, where it circulates largely as its choline ester sinapine. Its best-characterised property is antioxidant: two methoxy groups plus a para-hydroxyl make it a strong hydrogen donor, and it is a notable peroxynitrite scavenger ^{1,12Reference 1Nićiforović N · 2014Sinapic acid and its derivatives: natural sources and bioactivityView study →Reference 12Zou Y et al. · 2002Peroxynitrite-scavenging activity of sinapic acid isolated from Brassica junceaView study →}. Its deepest preclinical bench is neurological, but the honest headline holds across the page — every efficacy claim is in-vitro or rodent, with no human trials of the isolate.

1. Antioxidant

The dimethoxy/hydroxyl structure makes sinapic acid a strong hydrogen/electron donor — it scavenges DPPH, ABTS, superoxide and notably peroxynitrite ^{12Reference 12Zou Y et al. · 2002Peroxynitrite-scavenging activity of sinapic acid isolated from Brassica junceaView study →}, and induces Nrf2/HO-1 in organ-protection models ^{1Reference 1Nićiforović N · 2014Sinapic acid and its derivatives: natural sources and bioactivityView study →}.

Gap: chemical-assay antioxidant capacity does not establish in-vivo antioxidant benefit in humans; no isolate human data ^{1,12Reference 1Nićiforović N · 2014Sinapic acid and its derivatives: natural sources and bioactivityView study →Reference 12Zou Y et al. · 2002Peroxynitrite-scavenging activity of sinapic acid isolated from Brassica junceaView study →}.

2. Neuroprotective / anxiolytic

Sinapic acid shows anxiolytic-like behaviour in mice reported to be GABA-A-mediated (flumazenil-reversible) ^{4Reference 4Yoon BH et al. · 2007AnimalAnxiolytic-like effects of sinapic acid in miceView study →}, and neuroprotection in an amyloid-β Alzheimer’s mouse model ^{5Reference 52012AnimalNeuroprotective effect of sinapic acid in a mouse model of amyloid-β(1-42)-induced Alzheimer’s diseaseView study →} and a 6-OHDA hemi-parkinsonian rat model ^{6Reference 62015AnimalThe neuroprotective potential of sinapic acid in the 6-hydroxydopamine-induced hemi-parkinsonian ratView study →}, consolidated in a 2024 mechanism review ^{7Reference 72024Pharmacological activities and molecular mechanisms of sinapic acid in neurological disordersView study →}.

Gap: all animal; the GABA-A mechanism rests on one behavioural study, not receptor-confirmed across labs, and there is no human neuro/anxiety data ^{4Reference 4Yoon BH et al. · 2007AnimalAnxiolytic-like effects of sinapic acid in miceView study →}.

3. Anti-inflammatory

Sinapic acid suppresses NF-κB signalling and induces Nrf2/HO-1 across an acetic-acid ulcerative-colitis model ^{8Reference 82022AnimalSinapic acid ameliorates acetic-acid-induced ulcerative colitis in ratsView study →} and diabetic cardiomyopathy/nephropathy models ^{9Reference 92022AnimalSinapic acid ameliorates cardiac dysfunction and cardiomyopathy by modulating NF-κB and Nrf2/HO-1 in STZ-induced diabetic ratsView study →}.

Gap: the anti-inflammatory effect is embedded in disease-model studies, not isolated, with no human data ^{8,9Reference 82022AnimalSinapic acid ameliorates acetic-acid-induced ulcerative colitis in ratsView study →Reference 92022AnimalSinapic acid ameliorates cardiac dysfunction and cardiomyopathy by modulating NF-κB and Nrf2/HO-1 in STZ-induced diabetic ratsView study →}.

4. Antidiabetic

Sinapic acid is antihyperglycemic in diabetic rats ^{10Reference 102013AnimalAntihyperglycemic action of sinapic acid in diabetic ratsView study →}, with downstream heart and kidney protection via Nrf2/HO-1 and NF-κB in STZ models ^{9Reference 92022AnimalSinapic acid ameliorates cardiac dysfunction and cardiomyopathy by modulating NF-κB and Nrf2/HO-1 in STZ-induced diabetic ratsView study →}.

Gap: rodent STZ models only; the glucose-lowering magnitude and mechanism are not defined in humans ^{9,10Reference 92022AnimalSinapic acid ameliorates cardiac dysfunction and cardiomyopathy by modulating NF-κB and Nrf2/HO-1 in STZ-induced diabetic ratsView study →Reference 102013AnimalAntihyperglycemic action of sinapic acid in diabetic ratsView study →}.

5. Anticancer

Sinapic acid is pro-apoptotic and anti-proliferative in PC-3 and LNCaP prostate cancer cell lines ^{11Reference 112018Anticancer mechanism of sinapic acid in PC-3 and LNCaP human prostate cancer cell linesView study →}.

Gap: in-vitro cell lines only, with no in-vivo tumour or human evidence — clearly experimental ^{11Reference 112018Anticancer mechanism of sinapic acid in PC-3 and LNCaP human prostate cancer cell linesView study →}.

Mechanisms

Target / pathway	Effect	Relevant to
Direct radical scavenging (DPPH, ABTS, superoxide, peroxynitrite)	H-atom/electron donation neutralises ROS/RNS	antioxidant
Nrf2 / HO-1	induced → upregulated antioxidant defence	antioxidant, diabetic organ protection
NF-κB	suppressed → ↓ pro-inflammatory cytokines	anti-inflammatory, colitis, cardiomyopathy
GABA-A receptor (reported, flumazenil-reversible)	positive modulation → anxiolytic-like behaviour	anxiolytic
Apoptotic signalling (in vitro)	pro-apoptotic in prostate lines	anticancer (preclinical)

Pharmacokinetics

Sinapic acid is absorbed but extensively metabolised and conjugated — bioavailability is moderate at best. As a hydroxycinnamic acid it undergoes phase-II conjugation (glucuronidation/sulfation) and O-methylation, and in food it circulates substantially as its choline ester sinapine and as bound sinapate esters that require hydrolysis before absorption ^{1,3Reference 1Nićiforović N · 2014Sinapic acid and its derivatives: natural sources and bioactivityView study →Reference 32021ReviewPharmacological and therapeutic applications of sinapic acid — an updated reviewView study →}. Reviews consistently describe rapid clearance and metabolite-dominated exposure rather than high free-parent levels ^{1,2Reference 1Nićiforović N · 2014Sinapic acid and its derivatives: natural sources and bioactivityView study →Reference 2Chen C · 2016Sinapic acid and its derivatives as medicine in oxidative-stress-induced diseases and ageingView study →}. Rat studies also show sinapic acid can inhibit CYP-mediated metabolism of co-administered drugs, raising exposure of dasatinib and aripiprazole ^{13Reference 132023AnimalHerb-drug interaction: effect of sinapic acid on the pharmacokinetics of dasatinib in ratsView study →} — a genuine (rodent-only) interaction flag. No validated human pharmacokinetic parameters exist for the isolate.

Clinical trials

There are no registered or published human clinical trials of isolated sinapic acid for any indication. All efficacy data are in-vitro or rodent; human exposure is dietary only (mustard, rapeseed/canola products, whole grains, some vegetables and berries).

Last checked: July 2026.

Toxicity & Safety

Sinapic acid is a common dietary phenolic acid, consumed routinely in mustard, whole grains and Brassica vegetables, and reviews report no notable toxicity signal at studied doses with generally favourable safety in animal models ^{1,2,3Reference 1Nićiforović N · 2014Sinapic acid and its derivatives: natural sources and bioactivityView study →Reference 2Chen C · 2016Sinapic acid and its derivatives as medicine in oxidative-stress-induced diseases and ageingView study →Reference 32021ReviewPharmacological and therapeutic applications of sinapic acid — an updated reviewView study →}. The main theoretical caution is the CYP-inhibition interaction seen in rats for narrow-therapeutic-index drugs (dasatinib, aripiprazole) ^{13Reference 132023AnimalHerb-drug interaction: effect of sinapic acid on the pharmacokinetics of dasatinib in ratsView study →}, relevant only to hypothetical concentrated-supplement use, not to dietary intake.

Pregnancy & lactation

Dietary amounts fine; avoid isolated supplements. Sinapic acid as normal food (mustard, whole grains, vegetables) is considered safe, but concentrated/supplemental use has no reproductive-safety or human data and no established safe dose — so it is not recommended in pregnancy or lactation.

Dosage

There is no established human dose — sinapic acid is not sold or standardised as an isolate for a defined indication, and intake is dietary and unquantified in practice. All dosing figures in the literature are animal (mg/kg oral in rodent models) and do not translate to a human recommendation.

References