Rhus coraria

Other Names

ArkolDerici sumağıEkşi külüElm-leaved sumacElm-leaved sumachEssigbaumFärberbaumGerber-SumachGerbersumachGewürzsumachKankrasingKankrasringiKarkatakashringiKarkhadagachingiKarkkararingiRhus amoena Salisb.Rhus coriaria f. longifolia (Sennen) SennenRhus coriaria L.Rhus coriaria var. longifolia SennenRhus coriaria var. zebaria ShahbazRhus heterophylla C.C.Gmel.Rhus ornifolia Pall. ex Gueldenst.Rhus sumac O.Targ.Tozz.Rhus variifolia DC.RudhiSamakSammakSicilian sumacSicilya SumağıSimacSomaghSomakSomak ekşiSommaccoSommacco sicilianoSommacoSoumakiSumacSumac des corroyeursSumachSumagaSumagreSumakSumakhSumakiSumakkiSumaqaSummakSummāqSummaqSummaquaTanner's sumacTanner's sumachTitriToxicodendron coriaria (L.) KuntzeZumaqueZumaqueroZuurkruid

Synopsis

Rhus coriaria (Sumac): A Comprehensive Reference

1. Identity: Botanical Classification, Names, and Natural Source

Rhus coriaria L. (family Anacardiaceae) is a medicinal and aromatic plant historically known for its use both as a culinary spice and in traditional medicine. It is commonly known as sumac, a name derived from "sumaga," which means "red" in Syriac. Some people believe the word sumac originated from the Arabic word "summaq," which translates to "dark red," while others trace it to the Syriac "Sumaga." Etymologically, the genus name "Rhus" comes from the Greek "rhous," associated with the color red, due to the vibrant hue of its leaves in autumn and the color of its fruits; "coriaria" means "like leather," referring to its traditional use in the tanning industry.

Rhus coriaria is a hardy, drought-tolerant, deciduous shrub growing to 3 metres (10 ft) at a medium rate, or to a small tree up to 5 m (16 ft) high. The plant is a 3–5 m tall shrub, with long leaves having pinnate veins with 7–8 pairs of small oval leaflets of varying sizes. Rhus coriaria produces dark red drupes with thin flesh, which form dense clusters at branch tips, known as sumac bobs. The plant thrives well in subtropical and temperate climates, particularly in various parts of the Mediterranean, Asia, and northern Africa.

The Rhus genus has over 91 accepted species names in the Anacardiaceae family; Rhus coriaria L. is the only species in Iraq that grows wildly and/or is cultivated near the villages in the north of Iraq.

Common Forms and Preparations

For a long time, R. coriaria has been used as a spice by grinding the dried fruits with salt.
The fruit has a sour taste; dried and crushed, it is a popular spice in the Middle East, used especially in the spice mixture za'atar.
It is part of traditional mixtures such as za'atar in Levantine cuisine and dukkah in Egypt.
Several parts of sumac — including leaves, bark, and flowers — contain functional compounds used for tinctures in the local ethnobotanical tradition.
In modern research and supplementation contexts, sumac is most commonly administered as encapsulated dried powder, with doses in clinical trials typically ranging from 1 to 3 grams per day (see Section 8 below).
The leaves and the bark were traditionally used in leather tanning and contain tannic acid.

2. Traditional and Historical Use

Classical Antiquity

About 2,000 years ago, "De Materia Medica," a voluminous work by the Greek physician Pedanius Dioscorides (40–90 A.D.), described plentiful health merits of sumac, mainly as an anti-flatulent, stomach tonic, and diuretic. Pliny the Elder (1st century CE) described a "reddish berry" used by Sicilians to season fish and preserve meats; the Greek physician Dioscorides noted it as "skechakion," praising its cooling, astringent effect on wounds and digestive upsets. Mature fruits were also known well before lemons to the Europeans since the times of the ancient Romans, who appreciated its sourness and used it in vinaigrettes like lemons in modern times. Theophrastus and Dioscorides also described it as the fruit of a plant used for tanning.

Islamic and Persian Medicine

In addition to its use as a culinary herb and tanning agent, Rhus coriaria has been used in Middle Eastern and South Asian countries, for thousands of years, as a traditional medicine for the treatment of several diseases. Medieval Arab herbalists — al-Tabari and Ibn al-Baytar — incorporated sumac in formulations for diarrhea, dyspepsia, and skin ailments. Sumac has been used as a traditional remedy in the treatment of chronic symptoms of stroke, as described in the Canon of Medicine by Avicenna (Ibn Sina). In Persian traditional medicine, sumac (Rhus coriaria L.) is believed to have atheroprotective effects and is consumed in some Persian dishes.

Unani Medicine

In Iran, R. coriaria is traditionally used as a table spice, especially with rich dishes, and is highly recommended for adjustment of blood lipids in diabetic patients. The Unani system of medicine, which drew on Greco-Persian foundations, used sumac leaves in dyeing, tanning, and the fruits as medicine; the leaves had long been well known in Europe and in the East.

Documented Traditional Therapeutic Applications

Rhus coriaria, a common condiment, appetizer, and souring agent in the Mediterranean region with a long history in traditional medicine, has been prescribed for the treatment of many ailments including diarrhea, ulcer, hemorrhoids, hemorrhage, wound healing, hematemesis, and eye ailments like ophthalmia and conjunctivitis; the plant is also used as a diuretic, antimicrobial agent, abortifacient, and stomach tonic. Rhus coriaria has been used commonly in the remedy of ulcer, anal piles, hepatic disease, diarrhea, animal bites, and pain management, as well as for treatment of pharynx cold inflammations and seizing hemorrhage like hematemesis and hemoptysis. R. coriaria is traditionally used as herbal folk medicine in the treatment of stroke, diarrhea, hypertension, diabetes, atherosclerosis, measles, smallpox, and liver disease. The powdered fruits were also used to stimulate perspiration and reduce cholesterol.

3. Key Constituents and Active Compounds

As of recent counts, over 200 phytochemicals have been isolated from Rhus coriaria, including organic acids, phenolic acids, phenolic compounds conjugated with malic acid derivatives, flavonoids, isoflavonoids, hydrolysable tannins, anthocyanins, terpenoids, and other compounds such as butein, iridoid, and coumarin derivatives.

Major Polyphenolic Classes

Phenolic and gallic acids: The fruits and leaves of Rhus coriaria contain various phenolic acids such as gallic acid, ellagic acid, caffeic acid, and chlorogenic acid.
Flavonoids: Flavonoids identified include quercetin, rutin, kaempferol, luteolin, and apigenin.
Anthocyanins: Anthocyanins such as cyanidin, delphinidin, and peonidin are present. Hydroxyphenyl pyranoanthocyanins and other anthocyanins are responsible for the highly desired red pigments, accounting for the strong pigmentation capacity and colorant ability of sumac.
Tannins: Other significant phytochemical groups include gallotannins, ellagitannins, volatile compounds, organic acids, sugars, polysaccharides, sterols, and vitamins.

General Composition of the Dried Fruit

The overall composition of the dried sumac fruit is mainly composed of moisture (6–11.8%), essential oil content (1.0%), protein (2.3–2.6%), fiber (14.6–22.15%), ash (1.5–2.66%), water-soluble extract (63.8%), and fatty oil (17.4%). The mineral composition of sumac fruits, determined using ICP-AES, showed that K, Ca, Mg, P, Fe, Na, Zn, Mn, Cu, and Al are the predominant elements.

Variability and Standardization

Most studies on sumac have revealed similar phytochemical composition, with polyphenols such as tannins, flavonoids, and conjugated phenolics as major constituents. Importantly, geographic origin affects compound levels: flavonoids and phenolic acids, namely isoquercitrin and gallic acid, were more abundant in fruits from the population of San Biagio Platani (Sicily), while the population from Giarratana was characterized by a higher content of anthocyanins such as cyanidin-3-glucoside.

4. Established Mechanisms of Action

Antioxidant Activity

Most of the antioxidant potential and therapeutic roles of sumac are increasingly attributed to its constituent tannins, flavonoids, and phenolic acids. The antioxidant and antibacterial properties of sumac extract are mainly due to its phenolic components, such as tannins, gallic acid, and various flavonoids. Rhus coriaria appears to exert its protective effects by increasing the activities of detoxifying enzymes, including glutathione S-transferase (GST) and its isozymes in human plasma; additionally, it may reduce DNA damage through direct ROS scavenging activity. Gallic acid, a major constituent in sumac fruit, was also shown to reduce H₂O₂-induced DNA damage in human lymphocytes at a level comparable to sumac itself, suggesting gallic acid could account for a significant portion of the genoprotective effect.

Anti-inflammatory Mechanisms

The phenolic content and bioactivity of sumac extracts are associated with nuclear factor kappa B (NF-κB) impairment, considered the main putative anti-inflammatory mechanism. Sumac is abundant in phenolic antioxidants, including tannins and flavonoids, well-documented to exert beneficial effects on blood pressure; specifically, two key flavonoids — quercetin and apigenin — positively regulate blood pressure by enhancing the expression of angiotensin-converting enzyme-2 (ACE-2) in the kidneys.

Glycemic and Metabolic Mechanisms

In vitro studies have attributed inhibitory effects on pancreatic alpha-amylase and alpha-glucosidase, inhibition of SREBP1 gene expression, and increased expression of GLUT4 and PPAR-γ genes to sumac. These enzyme-inhibitory effects would be consistent with reduced postprandial glucose absorption.

Vasorelaxant and Cardiovascular Mechanisms

The vasorelaxant effect of sumac is mediated through stimulation of multiple signaling cascades, which include PI3-K/Akt, eNOS, nitric oxide (NO), soluble guanylate cyclase (sGC), cGMP, protein kinase G (PKG), COX, adenylyl cyclase/cAMP, and ATP-gated potassium channels. These findings strongly support the favorable potential cardio- and vasculo-protective action of Rhus coriaria and open the doors toward the use of this plant in amelioration of cardiovascular diseases such as atherosclerosis, aortic aneurysms, and hypertension.

Anti-H. pylori Gastric Mechanism

Sumac extracts inhibited IL-8 release (IC₅₀s < 70 μg/mL) during Helicobacter pylori infection and exhibited direct antibacterial activity at comparable concentrations (MIC = 100 μg/mL); this bioactivity was maintained after simulated gastric digestion and was associated with NF-κB impairment.

5. Scientific Evidence by Area of Use

5.1 Glycemic Control and Diabetes

This is one of the most studied therapeutic areas for sumac in clinical settings. Individual randomized controlled trials have generated positive findings, but meta-analytic pooling has produced inconsistent results.

Individual RCTs: A double-blind randomized controlled clinical trial conducted on 41 type 2 diabetic volunteers, randomly assigned to 3 g/day sumac powder (n=22) or placebo (n=19) over 3 months, showed significant decreases in serum glucose and HbA1c and also apoB levels at the end of the study (P < 0.0001, P = 0.002, and P < 0.0001, respectively).

Meta-analytic findings (2021): A random-effects meta-analysis of 6 clinical trials with 278 total participants suggested no statistically significant effects on the levels of fasting blood glucose (−7.08 mg/dl, 95% CI: −14.85 to 0.70, P = 0.07), glycosylated hemoglobin (HbA1c) (−0.48%, 95% CI: −1.01 to −0.04, P = 0.07), HOMA-IR (−0.97, 95% CI: −1.96 to 0.02, P = 0.05), or insulin following supplementation with sumac powder; the conclusion was that this meta-analysis showed no significant effects on any glycemic indices.

More recent meta-analysis (2025): A newer meta-analysis revealed a statistically significant decrease in insulin levels and HOMA-IR among participants treated with sumac, though these findings seem to contradict the results of a prior meta-analysis.

Evidence characterization: Many clinical trials have indicated the potent anti-diabetic property of sumac, but results on several glycemic indices have been inconclusive; more high-quality RCTs with longer duration are needed to further clarify the effects of sumac on blood glucose control, especially among patients with diabetes. The body of evidence is currently preliminary and mixed; heterogeneity between trials is substantial and study quality is variable.

5.2 Lipid Profile and Cardiovascular Risk

Rhus coriaria (sumac) is a medicinal spice particularly in Middle Eastern countries that is well known as an anti-lipid spice; a systematic review and meta-analysis was conducted including RCTs assessing its effect on blood lipid profiles. After reviewing these publications, 4 RCTs were potentially eligible and included; based on the results, RC has positive effects on different indices of the lipid profile.

Sumac supplementation enhances glycemic control and lipid metabolism, indicating potential cardiometabolic benefits in reducing cardiovascular disease risk factors. A comprehensive systematic review and meta-analysis assessed the impact of sumac supplementation on cardiovascular disease risk factors, including anthropometric measures, glycemic profile, inflammatory markers, and lipid profile, and also explored the dose-response relationship and optimal duration of supplementation.

Many clinical trials have investigated the effects of sumac supplementation on CVD risk factors; however, these studies have yielded contradictory findings.

Evidence characterization: Clinical evidence in this area is moderate but inconsistent. Most individual trials are small (fewer than 100 participants), and meta-analyses differ in the number and type of studies included. Results for LDL-C and total cholesterol reduction appear more consistently positive than for HDL-C or triglycerides.

5.3 Blood Pressure

Ardalani et al. (2016) reported that sumac (Rhus coriaria) extract significantly reduced blood pressure and BMI in hypertensive patients when used alongside the drug captopril, showing better results than captopril alone after eight weeks; the anti-hypertensive effect was attributed to the presence of flavonoids (such as luteolin, apigenin, and quercetin) and antioxidants in sumac.

Sumac was effective in the reduction of diastolic blood pressure in two studies; a pre-clinical study also showed a significant reduction in both systolic and diastolic blood pressure alongside increased nitric oxide expression.

Evidence characterization: Human clinical evidence is limited to a small number of trials. Mechanistic support from laboratory studies is more robust. Overall evidence is preliminary; well-powered, independent RCTs are lacking.

5.4 Non-Alcoholic Fatty Liver Disease (NAFLD)

Several clinical trials have investigated sumac specifically in NAFLD populations:

Trial 1 (84 participants, 12 weeks): Eighty-four patients diagnosed with NAFLD were included in a randomized double-blind placebo-controlled clinical trial; they were randomly assigned to receive 2,000 mg per day sumac powder (n=42) or placebo (n=42) for 12 weeks, with both groups also receiving a 500-calorie deficit diet plan. According to the results of this study, daily consumption of 2,000 mg of sumac powder in NAFLD patients for 12 weeks could decrease systolic blood pressure, AST, ALT, total cholesterol, LDL-C, and triglycerides.

Trial 2 (45 participants, 8 weeks): In a double-blind randomized controlled trial, 45 NAFLD patients were randomly divided into two groups; the intervention group received sumac capsules (3 g/day) with a balanced diet for 8 weeks while the placebo group received placebo with a balanced diet; anthropometric indices, lipid profile, fasting blood glucose, insulin, HOMA-IR, AST, ALT, hs-CRP, and malondialdehyde were measured. The results revealed a significant decrease in anthropometric indices including weight, BMI, waist circumference, body fat mass, body fat percentage, and visceral fat score.

In vitro studies also showed that sumac powder could protect hepatocytes against oxidative stress by reducing reactive oxygen species (ROS) production and lipid peroxidation, and through regulation of glutathione in the mitochondrial membrane.

Evidence characterization: Clinical evidence for NAFLD is emerging and promising but rests on a small number of relatively short trials. Results should be interpreted with caution.

5.5 Antioxidant Activity in Humans

One human study showed for the first time that sumac is a potent antioxidant which protects humans against oxidative DNA damage, and suggested that gallic acid may account for sumac's effects. A double-blind randomized placebo-controlled trial on 41 type 2 diabetic volunteers, assigned to either 3 g per day sumac powder or placebo for 3 months, showed a significant increase in paraoxonase 1 (PON1) activity and significant decreases in insulin and other markers.

5.6 Antimicrobial Activity

In vitro antimicrobial testing of R. coriaria leaf extract showed high inhibitory effects against Candida albicans (17 mm), E. coli (16 mm), P. aeruginosa (21 mm), S. aureus (17 mm), and K. pneumoniae (15 mm); LC-MS/MS analysis revealed that the leaves are rich in gallic acid, caffeic acid, and ascorbic acid, which may be strongly associated with these biological activities.

One study provided what the authors described as the first demonstration of the potential role of sumac as a nutraceutical useful in H. pylori-related gastritis.

Evidence characterization: Antimicrobial evidence is predominantly in vitro. No well-designed human clinical trials have validated antimicrobial effects against specific pathogens in vivo.

5.7 Anticancer Activity

The potential antitumor effects of sumac were explored in human cancer cell lines — MCF-7 (breast), PC-3 (prostate), and SKOV3 (ovarian) — using in vitro assays; apoptotic and cell survival assays were also conducted. In one such study, cytotoxicity was determined by MTT assay against MCF7 breast cancer cells and L929 mouse fibroblast cells; the extract was able to inhibit proliferation of MCF7 breast cancer cells with an IC₅₀ of 129.1 ± 9.27 μg/mL.

Evidence characterization: All anticancer evidence is in vitro only. No human clinical trials of sumac for cancer treatment or prevention have been published. These data are at the earliest stage of evidence and cannot be extrapolated to clinical use.

5.8 Inflammation Markers (hs-CRP)

A systematic review and meta-analysis was conducted to evaluate the impacts of sumac supplementation on high-sensitivity C-reactive protein (hs-CRP) concentrations, based on the PRISMA framework and registered in the PROSPERO database; databases including Web of Science, PubMed, Scopus, and Cochrane Library were searched up to February 2025. Dose-response findings from a separate meta-analysis suggested that a daily intake of approximately 2–3 g may be optimal for enhancing HDL levels and reducing inflammatory markers.

5.9 Metabolic Syndrome — Systematic Review

Reviewing 23 relevant studies (from PubMed, Web of Science, Scopus, EMBASE, Cochrane, Ovid, and Google Scholar, from 1966 to December 2020) using the Jadad scale to assess evidence quality, and covering English, Arabic, and Persian literature including both animal and human studies evaluating efficacy on any components of metabolic syndrome, demonstrated that R. coriaria is able to decrease the levels of blood glucose, glycated haemoglobin, serum insulin, and insulin resistance.

6. Body Systems and Health Areas

Several studies have demonstrated a wide range of pharmacological and biological activities of the different parts of Rhus coriaria, including antioxidant, antimicrobial, antidiabetic, cardioprotective, antidyslipidemia, antinociceptive, neuroprotective, dental protection, and anticancer effects. The following body systems have received at least some research attention:

Cardiovascular system: Lipid-lowering, antihypertensive, antiatherosclerotic, vasorelaxant, and antithrombotic activity have all been documented in laboratory or clinical contexts.
Endocrine/metabolic system: Antidiabetic, hypoglycemic, and insulin-sensitizing effects have been investigated in multiple human RCTs.
Gastrointestinal system: Traditional and some experimental evidence covers diarrhea, ulcer, hemorrhoids, and wound healing of gastrointestinal tissue. In vitro evidence exists for anti-H. pylori activity.
Hepatic system: In vitro studies showed sumac could protect hepatocytes against oxidative stress by reducing ROS production and lipid peroxidation. Clinical trials in NAFLD patients have shown reductions in liver enzymes AST and ALT.
Immune/inflammatory system: Anti-inflammatory mechanisms via NF-κB inhibition and suppression of pro-inflammatory cytokines have been reported in laboratory models.
Genitourinary system: Sumac fruits were used in folk medicine to treat urinary system issues.
Ocular health: Traditional medicine includes use for eye ailments like ophthalmia and conjunctivitis.
Oncology (preclinical only): In vitro cytotoxic activity against several cancer cell lines has been reported.

7. Dosage Forms and Dosages Reported in Studies

The following dosages are reported directly from the cited clinical literature and do not represent any recommendations:

3 g/day of sumac powder (encapsulated): Used in a 3-month double-blind RCT in 41 type 2 diabetic volunteers assessing effects on glycemic status, apolipoproteins, and total antioxidant capacity. Participants were randomly assigned into 3 g/day sumac powder (n=22) or placebo (n=19) groups over 3 months.
3 g/day of sumac powder (capsules): Used for 8 weeks in an NAFLD trial. In a double-blind randomized controlled trial, 45 NAFLD patients were randomly divided into two groups; the intervention group received sumac capsules (3 g/day) with a balanced diet for 8 weeks.
2,000 mg/day (2 g/day) of sumac powder for 12 weeks: Used in another NAFLD RCT in 84 patients. Patients were randomly assigned to receive 2,000 mg per day sumac powder (n=42) or placebo (n=42) for 12 weeks.
500 mg three times per day (1,500 mg/day) in capsule form: The case group received capsules containing 500 mg of powdered sumac fruits three times a day for one month in a dyslipidemia study.
Dose-response analysis: Dose-response findings from one meta-analysis suggested that a daily intake of approximately 2–3 g may be optimal for enhancing HDL levels and reducing inflammatory markers.

Sumac is also encountered as an aqueous extract, hydroalcoholic extract, and ethanolic extract in laboratory and preclinical research, though these forms are not standardized for clinical supplementation.

8. Safety Considerations and Interactions

General Safety Profile

Accumulating evidence supports the antibacterial, antinociceptive, antidiabetic, cardioprotective, neuroprotective, and anticancer effects of this plant; notably, toxicity studies show that sumac is very safe to consume by humans and has little toxicity. From the search of available literature, sumac has maintained a good track record for safety, with little or no reported adverse effects.

Anacardiaceae Family Cross-Reactivity

However, given that sumac belongs to the cashew family Anacardiaceae, people with allergies to those foods may want to take caution in the use of sumac to avoid any potential allergic reactions; it should also be noted that poison sumac (Toxicodendron vernix) also belongs to the Anacardiaceae. These are taxonomically distinct plants, but the family relationship warrants awareness in sensitized individuals.

Herb–Drug Interactions: Blood Pressure Medications

One study reported that sumac extract significantly reduced blood pressure in hypertensive patients when used alongside the drug captopril, showing better results than captopril alone after eight weeks. This co-administration finding suggests potential additive or synergistic hypotensive effects when sumac is used alongside antihypertensive drugs; the clinical significance requires further study.

Interactions with Antidiabetic Medications

Investigations into potential synergistic effects when sumac is combined with conventional medications or other natural compounds should be prioritized; such studies could illuminate combination strategies that maximize therapeutic benefits while mitigating potential adverse interactions, especially in patients with comorbid conditions such as metabolic syndrome, type 2 diabetes, or dyslipidemia. Given documented hypoglycemic effects in several RCTs, patients using insulin or oral hypoglycemic agents should be aware of the potential for additive blood glucose lowering.

Limitations of Existing Safety Data

Recent studies have pointed out that many medicinal herbs could exhibit some adverse effects; therefore, it is essential to consider this when evaluating safety. The clinical trials published to date have been short (3 months or less), with no long-term safety data in humans. Long-term safety trials in humans are scarce, and large-scale studies on cardiovascular endpoints remain lacking.

Exclusion Criteria Observed in Trials

In NAFLD trials, exclusion criteria included pregnant or lactating women, patients undergoing obesity surgeries or weight loss diets, and those taking herbal or biochemical medicines affecting liver function (ursodeoxycholic acid, phenytoin, amoxicillin, or lithium) or any medical treatment for NAFLD, or any dietary supplements (fiber, omega-3, and antioxidants) in the past three months. These exclusions indicate areas where interactions with sumac supplementation were considered a clinical concern by investigators.

References

Health Conditions

Health conditions that Rhus coraria may help support.

No conditions available.

Body Systems

Body systems that Rhus coraria may help support.

No body systems available.