# Brassica juncea (Mustard Greens)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/brassica-juncea
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-24
**Evidence Score:** 2 / 10
**Category:** Vegetable
**Also Known As:** Brassica juncea, Brown mustard, Indian mustard, Chinese mustard, Leaf mustard, Sarson, Rai saag, Oriental mustard

## Overview

Mustard greens (Brassica juncea) are a dark leafy green rich in the glucosinolate sinigrin (953–1319 µmol/100g fresh weight) and polyphenols such as sinapic acid and chlorogenic acid. These compounds inhibit carbohydrate-digesting enzymes α-amylase and α-glucosidase, suggesting a potential role in blood sugar management, though current evidence is limited to in vitro studies.

## Health Benefits

• Blood sugar regulation through α-amylase and α-glucosidase enzyme inhibition (preliminary evidence from in vitro studies only)
• [Antioxidant activity](/ingredients/condition/antioxidant) from polyphenols including sinapic acid and chlorogenic acid (in vitro evidence)
• Source of bioactive glucosinolates including sinigrin at 953-1319 mg/100g fresh weight (compositional data only)
• Rich in volatile compounds like allyl isothiocyanate with potential bioactivity (chemical analysis only)
• Nutrient-dense leafy green vegetable providing vitamins and minerals (general nutritive value noted)

## Mechanism of Action

Sinigrin, the predominant glucosinolate in Brassica juncea, is hydrolyzed by the enzyme myrosinase upon cell disruption to yield allyl isothiocyanate, which activates Nrf2-mediated [antioxidant](/ingredients/condition/antioxidant) response element (ARE) pathways, upregulating cytoprotective enzymes such as heme oxygenase-1 and [glutathione](/ingredients/condition/detox) S-transferase. The polyphenols sinapic acid and chlorogenic acid competitively inhibit α-amylase and α-glucosidase at the intestinal brush border, slowing glucose liberation from dietary starch and reducing postprandial glucose spikes. Additionally, chlorogenic acid has been shown to modulate hepatic glucose-6-phosphatase activity, potentially reducing endogenous glucose output, though this mechanism has not been confirmed in human trials for this specific species.

## Clinical Summary

The majority of evidence supporting Brassica juncea's health benefits derives from in vitro cell-free and cell-based assays rather than randomized controlled trials in humans. In vitro studies have demonstrated dose-dependent inhibition of α-amylase and α-glucosidase by mustard green extracts, with IC50 values comparable to some pharmaceutical reference compounds in controlled assay conditions. Glucosinolate content, particularly sinigrin at 953–1319 µmol/100g fresh weight, has been quantified analytically, but clinical translation of these enzyme-inhibition findings has not been established in adequately powered human trials. Overall, the evidence base is preliminary and promising, but broad health claims for blood sugar regulation or [antioxidant](/ingredients/condition/antioxidant) therapy in humans are not yet supported by clinical data.

## Nutritional Profile

Mustard greens (Brassica juncea) are a low-calorie, nutrient-dense leafy vegetable. Per 100g fresh weight: Energy ~26-27 kcal, Water ~90-91g, Carbohydrates ~4.7g, Protein ~2.7-3.0g (relatively high for a leafy vegetable), Fat ~0.4g, Dietary Fiber ~3.2g. Key vitamins: Vitamin K1 (phylloquinone) ~257-593 µg (highly variable by cultivar and growing conditions; bioavailability moderate due to fat-soluble nature, enhanced with dietary fat co-consumption), Vitamin C (ascorbic acid) ~70-130 mg (substantial contributor to daily requirements; sensitive to heat and oxidation), Vitamin A (as beta-carotene) ~140-580 µg RAE, Folate ~12-187 µg DFE (wide range reported across cultivars), Vitamin E (alpha-tocopherol) ~2.0-2.1 mg. Key minerals: Calcium ~115-150 mg (bioavailability reduced by oxalate content; estimated absorption ~40-50% compared to dairy calcium at ~30-32%), Potassium ~384 mg, Magnesium ~32-33 mg, Iron ~1.5-1.8 mg (non-heme; bioavailability enhanced by co-consumed Vitamin C), Phosphorus ~58 mg, Manganese ~0.48 mg, Zinc ~0.25 mg, Selenium ~0.9 µg. Bioactive glucosinolates: Sinigrin (allyl glucosinolate) at 953-1319 mg/100g fresh weight is the dominant glucosinolate; upon tissue disruption, myrosinase enzyme converts sinigrin to allyl isothiocyanate (AITC), the primary bioactive hydrolysis product responsible for characteristic pungency. Additional glucosinolates present at lower concentrations include gluconapin and glucobrassicanapin. Glucosinolate bioavailability and conversion to isothiocyanates is significantly reduced by cooking, which inactivates myrosinase; gut microbiota can partially compensate for myrosinase inactivation in cooked preparations. Polyphenols: Sinapic acid (hydroxycinnamic acid derivative) and sinapine (sinapic acid choline ester) are characteristic compounds; chlorogenic acid and kaempferol glycosides also present; total polyphenol content approximately 150-400 mg GAE/100g fresh weight depending on cultivar and post-harvest handling. Carotenoids: Lutein and zeaxanthin present (approximate combined ~3.0-4.0 mg/100g), relevant to macular health; fat-soluble and bioavailability enhanced with lipid co-consumption. Volatile compounds: Allyl isothiocyanate (AITC) is the principal volatile formed enzymatically from sinigrin hydrolysis; also includes 2-propenyl glucosinolate degradation products. Oxalates present at moderate levels (~0.03-0.05g/100g), which may modestly reduce calcium and iron bioavailability. Phytic acid present at low levels compared to legumes. Notably, mustard greens are a meaningful dietary source of Vitamin K, Vitamin C, and glucosinolate-derived bioactives, with nutrient retention best preserved through light steaming or minimal cooking time.

## Dosage & Preparation

No clinically studied dosage ranges have been established for Brassica juncea extracts, powders, or standardized forms due to the absence of human trials. Sinigrin content in leaves ranges from 953-1319 mg/100g fresh weight, but therapeutic dosing remains undetermined. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Mustard greens consumed in typical dietary quantities are generally regarded as safe for most healthy adults, but high-dose concentrated extracts may cause gastrointestinal irritation including bloating, cramping, or diarrhea due to allyl isothiocyanate release from sinigrin hydrolysis. Brassica juncea contains goitrogenic compounds that may impair [thyroid](/ingredients/condition/hormonal) iodine uptake when consumed in very large amounts, making it a potential concern for individuals with hypothyroidism or iodine deficiency, particularly when eaten raw. Individuals taking warfarin or other anticoagulants should use caution, as mustard greens are a significant source of vitamin K, which can antagonize anticoagulant therapy and require dosage adjustment. Safety during pregnancy has not been formally studied for concentrated extracts; dietary consumption is considered acceptable, but high-dose supplementation should be avoided without medical supervision.

## Scientific Research

No human clinical trials, RCTs, or meta-analyses specifically on Brassica juncea mustard greens were found in the research results. Available evidence consists solely of in vitro studies showing potential antihyperglycemic effects through enzyme inhibition and compositional analyses of bioactive compounds.

## Historical & Cultural Context

Brassica juncea has been used worldwide as both a food spice and in folk medicine, particularly within Asian traditional systems. Its use has centered on nutritive and medicinal values, including potential diabetes management through [antioxidant](/ingredients/condition/antioxidant) properties, though specific historical durations are not documented.

## Synergistic Combinations

Broccoli sprouts, turmeric, green tea extract, sulforaphane, vitamin C

## Frequently Asked Questions

### How much sinigrin is in mustard greens?

Brassica juncea contains approximately 953–1319 µmol of sinigrin per 100 grams of fresh weight, making it one of the richer dietary sources of this glucosinolate. Sinigrin content can vary based on cultivar, growing conditions, and preparation method, with cooking and boiling reducing levels by releasing and degrading glucosinolates into the cooking water.

### Can mustard greens help lower blood sugar?

Preliminary in vitro research shows that mustard green extracts inhibit the carbohydrate-digesting enzymes α-amylase and α-glucosidase, which are key targets for slowing postprandial glucose absorption—a mechanism similar to the diabetes drug acarbose. However, these findings come exclusively from laboratory studies, and no human clinical trials have confirmed that eating mustard greens or taking mustard green extracts produces meaningful reductions in blood glucose in people with diabetes or prediabetes.

### What antioxidant compounds are found in mustard greens?

Brassica juncea contains notable concentrations of the polyphenols sinapic acid and chlorogenic acid, both of which scavenge reactive oxygen species and activate Nrf2 antioxidant signaling pathways in vitro. Sinigrin hydrolysis also produces allyl isothiocyanate, which further induces endogenous antioxidant enzymes including glutathione S-transferase and heme oxygenase-1, though these effects have been demonstrated primarily in cell culture models rather than human subjects.

### Are mustard greens safe for people with thyroid conditions?

Mustard greens contain goitrogenic glucosinolates that, when hydrolyzed, can interfere with thyroid peroxidase activity and reduce iodine uptake by the thyroid gland, which is a concern primarily at high intake levels or in individuals already iodine-deficient. Cooking mustard greens significantly degrades myrosinase enzyme activity, reducing the conversion of glucosinolates to active goitrogens, so moderate cooked consumption is generally considered lower risk. Individuals with diagnosed hypothyroidism or those on thyroid hormone replacement therapy should consult their physician about appropriate intake levels.

### Do mustard greens interact with blood thinners like warfarin?

Yes, mustard greens are a significant dietary source of vitamin K1 (phylloquinone), which directly antagonizes the anticoagulant mechanism of warfarin by facilitating clotting factor synthesis in the liver. Patients stabilized on warfarin who suddenly increase or decrease their mustard green consumption may experience clinically significant changes in their INR (International Normalized Ratio), potentially increasing clotting or bleeding risk. These individuals should aim for consistent weekly intake of vitamin K-rich vegetables and inform their prescribing physician or anticoagulation clinic of any major dietary changes.

### What is the difference between raw and cooked mustard greens in terms of glucosinolate content?

Raw mustard greens retain their full glucosinolate content (953-1319 mg/100g), which are the precursors to bioactive compounds like sulforaphane and allyl isothiocyanate. Cooking, particularly boiling or steaming, can reduce glucosinolate levels by 20-50% depending on cooking duration and method, though some bioactive compounds may still remain or be converted during the heating process. For maximum glucosinolate intake, consuming mustard greens raw or lightly sautéed is preferable.

### Are mustard greens safe for pregnant or breastfeeding women?

Mustard greens are a nutrient-dense whole food that is generally safe for pregnant and breastfeeding women when consumed in typical dietary amounts as part of a balanced diet. However, high-dose supplements or concentrated extracts containing glucosinolates have not been adequately studied in pregnancy, so food-based consumption is preferred over supplemental forms during these periods. Pregnant women should consult their healthcare provider before using mustard greens supplements or extracts.

### How does cooking method affect the allyl isothiocyanate content in mustard greens?

Allyl isothiocyanate is generated when mustard greens are chopped or chewed, as enzymes (myrosinase) convert glucosinolates during cell disruption; cooking can deactivate myrosinase and reduce this conversion. Steaming or quick sautéing at lower temperatures preserves more enzymatic activity compared to boiling or high-heat cooking, which may minimize allyl isothiocyanate formation. For optimal volatile compound production, consuming mustard greens raw or minimally processed allows for maximal enzymatic conversion.

---

*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
*License: CC BY-NC-SA 4.0 — Attribution required. Commercial use: admin@hermeticasuperfoods.com*