Blood Pressure, Uric Acid, and Anti-Inflammatory Benefits

How celery's phthalides, apigenin, and seed extract support blood pressure, gout prevention, and whole-body inflammation

Celery is one of the most underestimated vegetables in a health-conscious kitchen. Beyond its use as a low-calorie snack, it contains a unique set of compounds — including 3-n-butylphthalide (3nB), apigenin, and luteolin — that have been shown in clinical trials to meaningfully lower blood pressure, reduce systemic inflammation, and inhibit the enzyme responsible for producing uric acid (the driver of gout) [1][4]. A randomized controlled trial found that celery seed extract lowered systolic blood pressure by about 11 mmHg in hypertensive patients over just four weeks [1]. The leaves, seeds, and stalks all contribute differently, making the whole plant worth knowing.

3-n-Butylphthalide: The Blood Pressure Compound

The compound that makes celery distinctive as a blood pressure food is 3-n-butylphthalide (3nB), a phthalide concentrated in celery seed oil and present at lower levels in the stalks. It works through two complementary mechanisms: it relaxes smooth muscle in arterial walls (allowing vessels to widen and pressure to drop) and has mild diuretic activity that reduces the fluid load the heart must manage. This combination produces meaningful blood pressure reduction — not just a marginal effect.

In a randomized, triple-blind crossover clinical trial, patients with mild-to-moderate hypertension received 1.34g of celery seed extract daily for four weeks [1]. Systolic blood pressure fell from 141 to 130 mmHg, diastolic from 92 to 84 mmHg, and mean arterial pressure from 108 to 99 mmHg — all statistically significant (p < 0.001). The placebo group showed no change. A 2025 meta-analysis pooling data from multiple randomized trials confirmed these findings and also found improvements in fasting blood glucose and total cholesterol in celery supplementation groups [4].

Apigenin and Luteolin: Anti-Inflammatory Flavonoids

Celery is one of the most concentrated dietary sources of apigenin, a flavonoid that works by inhibiting cyclooxygenase (COX) and lipoxygenase enzymes — the same enzymes targeted by ibuprofen and aspirin — and by suppressing NF-κB, a master regulator of inflammatory signaling [2]. Luteolin, also abundant in celery, adds overlapping anti-inflammatory effects and has demonstrated neuroprotective and hepatoprotective properties in mechanistic research.

Together, these flavonoids give celery a meaningful anti-inflammatory profile as a whole food. The leaves contain higher concentrations of apigenin and luteolin than the stalks and are often discarded — a wasteful habit if you're interested in the health benefits. Use celery leaves in salads, soups, and smoothies just as you would parsley.

Apigenin also has mild anxiolytic effects through partial agonism at GABA-A receptors, which may partly explain celery's traditional use as a calming food in Ayurveda and traditional European herbalism.

Gout and Uric Acid Reduction

Celery seed extract inhibits xanthine oxidase, the enzyme that converts purines into uric acid. By reducing xanthine oxidase activity, it can lower circulating uric acid — the root cause of gout flares and a contributor to kidney stone formation [3]. Rodent studies of hyperuricemia found that both aqueous and oil-based celery seed extracts significantly reduced serum uric acid and reduced inflammatory markers in joint tissue, with effects comparable in direction (if not magnitude) to pharmaceutical xanthine oxidase inhibitors like allopurinol at equivalent doses [3].

Celery seed is a traditional remedy for gout in both European and Ayurvedic herbalism, and the mechanistic evidence now offers a plausible biochemical explanation for that traditional use.

Stalks vs. Seeds vs. Leaves

Stalks: Provide fiber (pectins and cellulose), vitamin K, folate, vitamin C, and potassium. Lower concentrations of 3nB and flavonoids than seeds, but consumed in meaningful quantities as food. Excellent for blood pressure support through mineral profile alone.

Seeds (spice): Highly concentrated in 3nB and flavone glycosides. Use in cooking as a spice or look for standardized seed extract capsules (150–500mg in clinical studies). The flavor is intense — a little goes a long way.

Leaves: The most nutritionally dense part of the plant for flavonoid content. Treat them like an herb rather than discarding them.

Practical Notes

Juicing celery: Cold-pressed celery juice has become popular, and while the fiber is lost, it does concentrate the water-soluble compounds including nitrates, potassium, and some flavonoids. The evidence for celery juice specifically is thin, but a whole-food celery habit in any form is likely beneficial.

Celery seed supplement: If using for blood pressure or gout, look for standardized extracts. Effects can be additive with antihypertensive medications — inform your doctor if you take them.

Allergen note: Celery is one of the 14 major allergens listed in EU food law and commonly cross-reacts with birch pollen. If you have birch pollen allergy and experience oral tingling when eating raw celery, this is oral allergy syndrome. Cooking typically denatures the responsible proteins.

Oxalate content: Celery contains moderate oxalates. People with calcium oxalate kidney stones may want to moderate raw celery consumption and ensure adequate hydration.

See our Blood Pressure page for a broader overview of natural blood pressure interventions, and our Quercetin page for more on apigenin's close relative and its role in inflammation and longevity.

Evidence Review

Randomized Controlled Trial: Celery Seed Extract for Hypertension (Shayani Rad et al., 2022)

This randomized, triple-blind, placebo-controlled, crossover clinical trial enrolled 52 patients with mild-to-moderate essential hypertension and is the most rigorous human study on celery and blood pressure to date [1]. Participants received either celery seed extract (four 335mg capsules per day = 1.34g/day) or matching placebo for four weeks, then crossed over after a washout period. Key results in the celery arm:

Systolic BP: 141.2 ± 5.9 → 130.0 ± 4.4 mmHg (p < 0.001)
Diastolic BP: 92.2 ± 5.7 → 84.2 ± 4.9 mmHg (p < 0.001)
Mean arterial pressure: 108.5 ± 5.8 → 99.5 ± 4.7 mmHg (p < 0.001)
Pulse pressure: 49.0 ± 6.2 → 45.8 ± 6.0 mmHg (p < 0.01)

The placebo group showed no statistically significant changes in any blood pressure parameter. Additionally, fasting blood sugar, LDL cholesterol, and total cholesterol improved significantly in the celery group, and kidney and liver function markers remained stable — confirming the safety profile. The crossover design strengthens causal inference by using each participant as their own control. Limitations: small sample (n=52); four-week duration does not confirm long-term efficacy; the extract concentration may differ from commercially available products; patients on blood pressure medications were excluded, so combination effects are unknown.

Systematic Review and Meta-Analysis (Liu et al., 2025)

The most current synthesis of human evidence, this 2025 meta-analysis published in Frontiers in Nutrition pooled data from available randomized controlled trials assessing celery in various forms (whole food, juice, and extract) on cardiometabolic outcomes in adults [4]. The pooled analysis confirmed significant reductions in both systolic and diastolic blood pressure across trials. Additionally, significant improvements were found in fasting blood glucose and total cholesterol. The authors noted substantial heterogeneity in preparation type, dose, and duration across included studies — a limitation that makes precise dosing recommendations difficult. The review calls for standardized extraction protocols and larger, longer trials before clinical recommendations can be formalized. Despite heterogeneity, the consistent direction of effect across multiple trials and preparation types strengthens confidence in celery's blood pressure and metabolic effects.

Antioxidant and Phytochemical Review (Kooti and Daraei, 2017)

This systematic review published in the Journal of Evidence-Based Complementary and Alternative Medicine identified and characterized the major bioactive compounds in celery responsible for its health effects [2]. Celery's primary phytochemicals include:

Apigenin and luteolin (flavones): COX and lipoxygenase inhibitors; NF-κB suppression; GABA-A receptor modulation
Caffeic acid and p-coumaric acid (phenolic acids): free radical scavengers with demonstrated lipid peroxidation inhibition in standardized assays
3-n-Butylphthalide (phthalide): vasodilator via smooth muscle relaxation; calcium channel antagonism; mild diuretic
Apiin and other flavone glycosides (in seeds specifically): xanthine oxidase inhibition; uric acid reduction

The review found that celery extracts demonstrated consistent antioxidant activity across multiple assay types (DPPH, ABTS, ferric reducing power), with the seed fractions generally showing the highest potency. The authors noted that while in vitro antioxidant assays have limited direct translation to in vivo outcomes, the consistent concentration-dependent activity and the alignment with clinical findings in blood pressure research supports mechanistic plausibility. Limitations of the review: the field was relatively early at time of publication; many cited studies were in animals or in vitro; human clinical trial data was sparse in 2017 (now more available).

Animal Models: Gout and Hyperuricemia (Li et al., 2019)

This rodent study tested celery seed aqueous extract (CSAE) and celery seed oil extract (CSOL) in two separate animal models of hyperuricemia and gouty arthritis induced by potassium oxonate and yeast extract [3]. Key findings:

Both CSAE and CSOL significantly reduced serum uric acid levels in hyperuricemic mice (p < 0.05 vs. model group)
Both extracts reduced xanthine oxidase activity in serum and liver tissue — the mechanism of action for uric acid reduction
In the gouty arthritis model, both extracts reduced joint swelling and inflammatory markers including TNF-α, IL-1β, and IL-6 in joint tissue
CSOL showed somewhat stronger uric acid-lowering effects, while CSAE showed stronger anti-inflammatory effects, suggesting different active compound profiles between aqueous and oil fractions

The xanthine oxidase inhibition data provides direct mechanistic support for celery's traditional use in gout management. However, the animal-to-human translation has limitations: rodent uric acid metabolism differs somewhat from humans (humans lack the enzyme uricase that most mammals have), and doses used in animal studies are not directly comparable to typical human consumption. No randomized human trials specifically on celery and gout have been published as of 2025, making this a mechanistically supported but clinically unconfirmed application. Preliminary evidence is promising enough to warrant human trials.

Evidence Strength Summary

The blood pressure evidence is the strongest — supported by a well-designed crossover RCT in humans, a 2025 meta-analysis, and a plausible, well-characterized mechanism (3nB-mediated vasodilation). The anti-inflammatory and antioxidant properties are supported by phytochemical characterization and mechanistic data but lack large-scale human trials specifically targeting inflammatory outcomes. The gout and uric acid evidence is mechanistically solid at the animal level but awaits human clinical confirmation. Overall, the evidence base supports celery (particularly seed extract) as a meaningful food-based tool for blood pressure management and a promising candidate for gout prevention — with a better safety profile than most pharmaceutical alternatives.

References

Effect of celery (Apium graveolens) seed extract on hypertension: A randomized, triple-blind, placebo-controlled, cross-over, clinical trialShayani Rad M, Moohebati M, Mohajeri SA. Phytotherapy Research, 2022. PubMed 35624525 →
A Review of the Antioxidant Activity of Celery (Apium graveolens L)Kooti W, Daraei N. Journal of Evidence-Based Complementary and Alternative Medicine, 2017. PubMed 28701046 →
Anti-gouty arthritis and anti-hyperuricemia properties of celery seed extracts in rodent modelsLi S, et al.. Molecular Medicine Reports, 2019. PubMed 31702020 →
Effects of celery (Apium graveolens) on blood pressure, glycemic and lipid profile in adults: a systematic review and meta-analysis of randomized controlled trialsLiu D, Zhao H, Xu H, Hu J. Frontiers in Nutrition, 2025. PubMed 40765738 →