Black gram

Black Gram (Vigna mungo L. Hepper)

1. Identity, Botanical Classification, and Common Forms

Botanical and Chemical Identity

Black gram (Vigna mungo L. Hepper) consists of small, black-coloured beans featuring prominently in Asian cuisine, which basically originated from India. Botanically, the species belongs to the family Fabaceae (also designated Leguminosae). More precisely, the plant is an erect, hairy annual with long twining branches; its flowers are small and yellow in colour, and its fruits are cylindrical hairy pods containing one to four seeds each. Black gram grows on an erect, hairy bush with stems diffusing from the base and reaching up to 30–100 cm in height with trifoliate leaves. The fruit looks cylindrical while its hairy pods contain up to 4 to 10 black seeds.

The accepted current botanical name is Vigna mungo (L.) Hepper. The species was previously classified as Phaseolus mungo L. before reclassification into the Vigna genus. It is commonly referred to as Black Gram, Urad daal, and Maash. In Ayurveda, the plant is known as Māsha. In regional Indian languages, it is called minapappu in Telugu and Vulundhu in Tamil.

Common Forms and Preparations

Black urad (sabut) retains the black seed coat intact, conferring higher fibre, polyphenols, and a richer flavour. White urad (dhuli) is split and dehusked — milder in flavour, better suited for fermented batters, faster to cook, and easier to digest. Dal makhani uses whole black urad for its rich texture; idli batter requires the white urad for its unique protein–mucilage properties. Black gram sprouts are also popularly consumed in several regions, including Asia and Western countries; the sprouting process allows several biochemical changes, resulting in improved nutritive quality, including by promoting protein digestibility, increasing the availability of macronutrients, and diminishing antinutrient factors.

Additional culinary and traditional medicinal forms include decoctions of the whole seed or root, pastes applied topically, fermented preparations (idli, dosa), and medicated gruels. Properly processed seeds, sprouts, or decoctions are used therapeutically in a variety of traditional formulations; classical preparations such as Vedhanika (a traditional gruel) enhance digestibility and nourishment.

2. Traditional and Historical Use

Ayurvedic Medicine (Indian Subcontinent)

Black gram (Vigna mungo), commonly known as urad dal, has been an esteemed ingredient in traditional medicine for centuries, particularly in Ayurveda and Siddha systems of healing in South Asia. It is traditionally used for strangulated bowel syndrome, dyspepsia, constipation, neuropathy, hepatopathy, gastritis, diarrhoea, rheumatism, and diabetes, among other conditions.

Known in Ayurvedic classics as Urad (Phaseolus mungo), black gram is described for its nourishing, strengthening, and Vata-pacifying properties. It is considered especially beneficial in conditions associated with Vata imbalance such as debility, emaciation, joint disorders, nervous weakness, and reproductive tissue depletion. Due to its Snigdha (unctuous), Guru (heavy), and Ushna (heating) qualities, it promotes strength, stability, and tissue nourishment, particularly of Mamsa (Muscle Tissue) and Shukra Dhatu (Reproductive Tissue).

Classical Ayurvedic texts such as the Charaka Samhita and Sushruta Samhita mention black gram as an ingredient in topical treatments addressing skin conditions like roughness and inflammation. As cited in the Charaka Samhita, rice prepared with black gram, sesame, green gram, and milk is considered strength-promoting, refreshing, and nourishing. According to Ayurvedic characterisation, black gram possesses emollient, thermogenic, diuretic, aphrodisiac, nutritious, galactagogue, appetiser, laxative, and styptic properties, and is regarded as a nervous tonic. Medicinally, it has been used in traditional Ayurvedic practice to address pain, Parkinson's disease, sciatica, erectile dysfunction, premature ejaculation, asthma, cardiac diseases, loss of taste, constipation, neurological disorders, paralysis, facial paralysis, and debility.

In both Jainism and Ayurveda, black gram is revered for its dietary importance and medicinal properties, being used in rituals, and it is considered an aphrodisiac linked to rituals and well-being. Historically, it was given to those recovering from illness, women needing to boost breast milk production, or individuals seeking to increase vitality and reproductive strength. It is also used as a medicinal herb in Panchakarma (Ayurvedic detoxification) therapies.

Cross-Cultural and Regional Traditional Uses

Black gram is widely grown across India, especially in Tamil Nadu, Uttar Pradesh, and Madhya Pradesh, flourishing in subtropical climates. Regional culinary traditions differ considerably: in Punjab it becomes the rich, creamy dal makhani slow-cooked with butter and cream; in South India the same lentil is ground and fermented into light idlis or crisp dosas; in Maharashtra it blends into spicy chutneys; in Tamil Nadu it is tempered with mustard seeds and curry leaves; and in Nepal it is simmered into thick, warming stews.

Traditionally, V. mungo is mentioned for its beneficial effects in ailments like ostalgia, abscess, inflammation, rheumatism, and asthma; the seeds are also described as diuretic, emollient, appetiser, thermogenic, nervine tonic, laxative, aphrodisiac, astringent, styptic, and galactagogue. They are also traditionally used in managing epistaxis, schizophrenia, scabies, haemorrhoids, gonorrhoea, leukoderma, heart problems, indigestion, anorexia, constipation, hepatopathy, neuropathy, hysteria, nervous debility, partial paralysis, facial paralysis, and weakness of memory, as well as in erectile dysfunction and premature ejaculation.

3. Key Constituents and Active Compounds

Macronutrient Composition

Black gram is a major pulse crop and has a protein-rich (approximately 24%) and carbohydrate-rich (approximately 59.6%) composition; it also contains high amounts of calcium, phosphorus, and iron. The average content of starch, total soluble sugars, proteins, and lipids across cultivars is approximately 43.5%, 4.84%, 22.0%, and 1.1%, respectively. When raw, black gram contains high levels of protein (25 g/100 g), potassium (983 mg/100 g), calcium (138 mg/100 g), iron (7.57 mg/100 g), niacin (1.447 mg/100 g), thiamine (0.273 mg/100 g), and riboflavin (0.254 mg/100 g).

Phytochemicals and Bioactive Compounds

V. mungo contains phytochemicals including alkaloids, flavonoids, saponins, steroids, tannins, phenolic compounds, fatty acids, carbohydrates, amino acids, vitamins, and carotenoids. The seed coat of Vigna mungo is found to be rich in flavonoids, glycosides, alkaloids, phenolics, carbohydrates, and a group of polyphenolic antioxidants that are apparently responsible for free radical scavenging effects.

Gallic, protocatechuic, vanillic, genistic, and syringic acids are the primary hydroxybenzoic acids present in black gram. Ferulic acid is the major hydroxycinnamic acid derivative found in black gram, and it has been associated with antioxidant, anti-inflammatory, antidiabetic, anticancer, antiaging, antiapoptotic, hepatoprotective, radioprotective, neuroprotective, antiatherogenic, hypotensive, and pulmonary protective properties. Ferulic acid has also been noted to be more stable over longer periods of time than vitamin C.

Black gram accumulates many kinds of flavonol and anthocyanin glycosides; the young leaves accumulate kaempferol 3-O-robinobioside-7-O-rhamnoside (robinin), which possesses galactose at the 3-O position, as the predominant flavonoid. The composition includes the specific flavonoid vitexin, alongside proteins, carbohydrates, and phenolic compounds. A broader survey of bioactive components of Vigna mungo identified flavonoids, isoflavonoids, phytoestrogens, phenolic acids, enzymes, fibres, starches, trypsin inhibitors, phytic acid, lectins, saponins, tocopherols, fatty acids, and proteins.

The mineral composition of the seed coat has been shown to be rich in calcium, sodium, potassium, magnesium, iron, copper, zinc, and manganese.

Antinutritional Factors

Antinutritional factors in black gram include phenolic compounds, tannins, saponins, phytic acid, trypsin inhibitors, and enzymes related to them such as acid- and alkaline phosphatases, and α-galactosidase. The major nutritional constraint with raw Vigna mungo seeds is their high content in condensed tannins and trypsin inhibitors. The seeds also contain significant quantities of flatulence-inducing oligosaccharides — raffinose and stachyose. Soaking for 8 hours (discarding the soak water) and thorough cooking can reduce this; fermentation, as in idli, eliminates most of the flatulence risk.

4. Scientific Evidence by Area of Use

4.1 Antioxidant Activity

In vitro antioxidant activities of aqueous, ethanol, and 80% ethanolic extracts of Vigna mungo seed coat have been assessed. The seed coat was found to contain 27.52% carbohydrates, 10.07% protein, and 48.67% crude fibre; the content of total phenolics and flavonoids was significantly higher in the 80% ethanolic extract than in other extracts. The higher antioxidant potential was shown by the 80% ethanolic extract in DPPH and SOD assays, whereas the aqueous extract showed more scavenging activity in the H₂O₂ assay.

The evidence base for antioxidant activity is predominantly in vitro. The seed coat of Vigna mungo not only exhibits good antioxidant properties but is also rich in phytochemicals, minerals, protein, and fibre. No controlled human clinical trials specifically evaluating the antioxidant efficacy of black gram extract in isolation have been identified in the reviewed literature.

4.2 Glycaemic Regulation and Antidiabetic Effects

Black gram, particularly in its sprouted form, is popularly consumed; the sprouting process promotes protein digestibility, increases macronutrient availability, and diminishes antinutrient factors. Black gram contains vitexin and other flavonoids and phenolic compounds that may benefit faster removal of free fatty acids from circulation, reducing total cholesterol by increasing lipoprotein lipase activity. The extract has a low glycaemic index and high fibre content.

When normal and alloxan-induced diabetic guinea pigs were fed a whole-seed diet of Phaseolus mungo (black gram) for four weeks, blood glucose, serum total lipids, triglycerides, and the esterified fraction of cholesterol were significantly lowered, while serum phospholipid was unaltered. The total cholesterol/phospholipid ratio also decreased in both normal and diabetic animals, indicating an antiatherogenic effect. This is an animal study and cannot be extrapolated directly to humans.

The seed husks of some legumes, including black gram, are a source of phytochemicals with bioactive qualities such as antioxidant, antidiabetic, anti-obesity, antimicrobial, and anticancer activities, according to a 2025 PMC review of black gram husk. In a multi-omics study of mung bean species including black mung (V. mungo), all mung samples exerted noteworthy dose-dependent inhibitory potential towards α-amylase and α-glucosidase enzymes; gamma-aminobutyric acid (GABA), gallic acid, and beta-sitosterol were highlighted as possible efficacy metabolites mediating antidiabetic potential. This study was conducted in vitro and using metabolomics analysis, not a human trial.

Overall, the antidiabetic evidence for black gram remains preliminary, based on animal models, cell-based assays, and in vitro enzyme-inhibition studies. No published randomised controlled trials in humans were identified in the reviewed literature.

4.3 Anti-Inflammatory and Anti-Osteoarthritic Activity

Pharmacological studies have reported that V. mungo possesses anti-inflammatory activity, analgesic activity, anticancer activity, hepatoprotective activity, and MMP (matrix metalloproteinase) inhibiting activity.

A rodent study evaluated the effect of Vigna mungo hydroalcoholic extract (VMHA) in a papain-induced osteoarthritis (OA) rat model. OA was induced by intra-articular injection of papain (4% w/v) along with cysteine (0.03 M) on days 1, 4, and 7, and VMHA was administered orally at three doses (100, 200, and 400 mg/kg) after the last papain injection. The anti-osteoarthritic activity was evaluated by measuring knee joint diameter, grip strength, locomotion activity, and hanging time. Results showed that VMHA improved the inflammatory condition at all doses, but statistically significant (P < 0.05) attenuation of inflammation was present only at 400 mg/kg. Grip strength, locomotion activity, and hanging time were also significantly improved at 100 mg/kg, but the two higher doses were not found to be effective for those endpoints. This is an animal study only; no human clinical data exist for this endpoint.

4.4 Hepatoprotective and Nephroprotective Effects

Reported pharmacological activities of V. mungo compounds — based on in vitro and in vivo evidence — include hepatoprotective and nephroprotective activities, in addition to antioxidant, antidiabetic, anti-hyperlipidaemic, immunostimulatory, antibacterial, anthelmintic, thrombolytic, anti-inflammatory, analgesic, anticonvulsant, nootropic, anti-osteoarthritic, aphrodisiac, spermatogenic, and anticancer activities. The Phytochemistry Reviews (2024) comprehensive review by Hamid et al. (published in Springer Nature, indexed on PubMed) compiled available evidence on hepatoprotective activity from preclinical sources, including a referenced study evaluating the aqueous extract of Vigna mungo on rifampicin-induced toxicity in albino rats.

Evidence quality note: Scientific data in support of the biological activities of V. mungo are currently scarce, and more in-depth research to determine clinical efficacy has been called for. All available hepatoprotective and nephroprotective data come from preclinical (animal) models.

4.5 Nootropic (Cognitive) Effects

Evaluation of nootropic activity of Vigna mungo Linn. on scopolamine-induced cognitive dysfunction in mice has been published. Traditional Ayurvedic sources list weakness of memory as one of the conditions addressed by black gram preparations. The nootropic evidence is strictly preclinical (animal model); no human trial data were identified.

4.6 Aphrodisiac and Spermatogenic Effects

An experiment conducted on Sahiwal cattle was designed to determine the effect of supplementation of dried and ground black gram foliage (Vigna mungo L.) on milk composition with special reference to arginine content to understand the Ayurvedic concepts highlighted in Vajikarana Chikitsa (aphrodisiac therapy). Classical Ayurvedic texts describe fresh black gram as an ingredient in both virilific ghee and virilific pill preparations. The spermatogenic and aphrodisiac claims associated with black gram in the scientific literature derive from preclinical and traditional sources; no human clinical trial data were identified.

4.7 Cardiovascular and Lipid-Modulating Effects

Pulses are valued for their protein content as well as their low glycaemic index and are commonly included in diets in the Indian subcontinent. Daily intake of pulses is suggested to reduce the risk of cardiovascular diseases, digestive tract diseases, and obesity. For black gram specifically, anti-hyperlipidaemic activity has been noted in animal studies, and feeding of whole black gram seeds was observed to significantly lower blood glucose, serum total lipids, triglycerides, and the esterified fraction of cholesterol in both normal and diabetic guinea pigs, with the total cholesterol/phospholipid ratio also decreasing — indicating an antiatherogenic profile. This evidence remains animal-level only.

4.8 Digestive and Gastrointestinal Effects

Germination, which breaks seed dormancy by activating endogenous enzymes, is identified as the most effective and economical option to boost the nutritional qualities of black gram and reduce the activity of antinutrients; germination has been associated with enhanced bioactive compounds including those with antidiabetic, antihypertensive, and anticancer activities in cereals and pulses generally. Dietary fibre in pulses like black gram is broadly associated with improved bowel regularity and gut function, consistent with the traditional attribution of laxative properties.

5. Body Systems and Health Areas Associated with Black Gram

• Musculoskeletal system: Decoction of black gram is traditionally used in Vata disorders such as arthritis, joint pain, fatigue, and weakness.
• Nervous system: Black gram is regarded as a good nervous tonic and has traditionally been associated with managing neurological disorders, paralysis, facial paralysis, Parkinson's disease, sciatica, and debility.
• Reproductive system: Black gram promotes strength, stability, and tissue nourishment particularly of Shukra Dhatu (Reproductive Tissue); classical texts mention its role in improving vitality, semen quality, and physical endurance.
• Digestive system: Traditional uses include strangulated bowel syndrome, dyspepsia, constipation, gastritis, and diarrhoea.
• Liver and kidneys: Traditional use includes hepatopathy (liver disorders), and preclinical pharmacological work has been conducted on hepatoprotective and nephroprotective activities.
• Skin: In Ayurvedic practice, black gram is used in topical preparations such as pastes and oils for improving skin texture, treating dryness, and supporting wound healing; it is also included in herbal formulations for softening and moisturising the skin.
• Cardiovascular system: Traditional and preclinical associations with antiatherogenic and lipid-modulating effects, as noted above.
• Metabolic/endocrine: Low glycaemic index, alpha-glucosidase inhibition, and antidiabetic properties studied in vitro and in animal models.

6. Dosage Forms and Reported Dosages

Black gram is consumed most commonly as a dietary pulse in its whole, split, or dehulled form. Reported dosages from preclinical pharmacological studies are in the following ranges:

• In a rat osteoarthritis model, Vigna mungo hydroalcoholic extract (VMHA) was administered orally at doses of 100, 200, and 400 mg/kg body weight after the last papain injection.
• Significant anti-inflammatory attenuation was observed at the 400 mg/kg dose; improvement in grip strength, locomotion activity, and hanging time was significant at 100 mg/kg.
• In the guinea pig lipid study, animals received a whole-seed diet of black gram for four weeks, with effects measured on blood glucose, serum lipids, triglycerides, and cholesterol fractions.

No human clinical dosage has been established for black gram extract as a dietary supplement in any reviewed source. Dosage data come exclusively from preclinical (animal) models. As a dietary staple, black gram is consumed in India and South Asia in amounts ranging from approximately 30–100 g of dry seeds per serving as part of regular meals, though no standardised therapeutic dosage has been defined in the scientific literature reviewed.

7. Processing Effects on Bioavailability and Antinutrients

Various processes like cooking, soaking, and germination affect the bioactive components of black gram. Domestic processing and cooking methods — including soaking, ordinary and pressure cooking of soaked and unsoaked seeds, and sprouting — significantly lowered phytic acid, saponin, and polyphenol contents. Soaking for 18 hours removed 31–37% of the phytic acid; the extent of removal was higher with longer soaking periods. Loss of the antinutrients was greater when soaked seeds were cooked rather than unsoaked seeds.

Germination is identified as the most effective and economical option to boost the nutritional qualities and reduce antinutrient activity in pulses. Germination resulted in reductions of phytic acid by up to 75.65% and trypsin inhibitor activity by up to 39.20% in pulses studied; however, saponin levels showed a significant increase, rising nearly threefold with germination.

Heat treatments including boiling, roasting, microwave cooking, and autoclaving bring about total removal of trypsin inhibitors. Processing can enhance the use of pulses by reducing the levels of antinutritional factors and by modifying the structures of starch granules and protein bodies, which in turn modulates their functional properties.

8. Safety Considerations and Notable Interactions

Purine Content and Gout / Hyperuricaemia

Urad dal has high purine content. People with gout, kidney stones, or elevated uric acid should limit urad dal to 50 g cooked per day and stay well hydrated. Purines are natural substances present in many foods; when the body breaks them down, uric acid is produced. Under normal circumstances, this uric acid dissolves in the bloodstream and is removed through urine. Problems arise when the body either produces too much uric acid or struggles to eliminate it efficiently — excess can accumulate and may lead to gout attacks or joint discomfort. Legumes, including urad dal, typically contain moderate levels of purines; nutritional analyses suggest most pulses provide roughly 50–150 mg of purines per 100 grams. By comparison, organ meats, certain fish, and red meat contain significantly higher amounts.

Kidney Considerations and Oxalate/Phosphorus

High oxalate content in urad dal may contribute to the formation of kidney stones in susceptible individuals. The high phosphorus content (385 mg/100 g) requires restriction in chronic kidney disease (CKD).

Digestive Tolerance

Some people with sensitive digestive systems may experience discomfort when consuming urad dal, especially if it is not cooked thoroughly. The significant raffinose and stachyose content can cause flatulence; soaking for 8 hours, discarding the water, and thorough cooking reduce this effect. Fermentation, as in idli, eliminates most of the flatulence risk.

Allergy

While rare, some individuals may be allergic to urad dal, which can result in allergic reactions such as itching, hives, or gastrointestinal distress. Germination for ten days alters the immunoreactivity of black gram vicilin proteins; a study investigated the effect of germination on the immunoreactivity of black gram and mung bean vicilins using ELISA and Western blot analyses. Electrophoretic analysis of sprouted black gram showed a gradual decrease in the 40–60 kDa polypeptides with a concomitant increase in the 9–26 kDa polypeptides — suggesting that protein structure, and potentially allergenicity, is altered by sprouting.

Blood Glucose–Lowering Interactions

Urad dal can interact with certain medications, particularly those that affect blood sugar levels. People taking medication for diabetes should monitor their blood sugar levels when incorporating urad dal into their diet. This reflects the documented in vitro and animal-level antidiabetic activity through enzyme inhibition (α-amylase and α-glucosidase) and potential additive effects.

Evidence Quality Summary

The overall quality of evidence supporting therapeutic uses of black gram as a dietary supplement is low to very low by contemporary clinical research standards. Scientific data in support of the biological activities of V. mungo are currently scarce, and more in-depth research is needed to determine clinical efficacy. The majority of pharmacological claims derive from in vitro assays and animal experiments. No adequately powered, peer-reviewed randomised controlled trials in human subjects evaluating black gram extract or powder as a therapeutic agent have been identified in the reviewed peer-reviewed literature. Black gram's nutritional profile — including its protein, fibre, micromineral, and polyphenol content — is well documented and broadly consistent with the known health-associated properties of legumes in general.

References

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