Introduction

Bunium persicum Boiss. Fedtsch., commonly referred to as black cumin or black caraway, is a lesser-known but significant medicinal, aromatic, and culinary spice belonging to the family Apiaceae. Native to Western Asia, this species is primarily found in the dry temperate regions of the Western Himalayan zone in India, where it is locally known as Kala Jeera. The high-altitude regions of Jammu and Kashmir, Himachal Pradesh, and the Almora hills of Uttarakhand are key centers for its cultivation in India [1, 2].

Among the prominent regions for B. persicum cultivation in the northwestern Himalayas, the Gurez valley, situated along the Indo-Pakistan border, is a major production area in Jammu and Kashmir. While B. persicum is a distinct species, variation in its cultivation methods and local nomenclature exists across different regions [3, 4].

In India, several related species or varieties of Bunium are recognized, including:

• 1.

  B. persicum (Kala Jeera): The most commonly known and utilized species, particularly in Kashmir and Himachal Pradesh.

• 2.

  Bunium bulbocastanum (earthnut or great pignut): Although distinct from B. persicum, it is a related species and is sometimes used similarly in traditional medicinal practices.

• 3.

  Bunium elegans: A less well-known species, which also occurs in similar high-altitude regions but is not as widely used or studied as B. persicum.

These species share ecological niches but vary in their regional importance and applications in traditional medicine, as well as in the local agricultural practices surrounding their cultivation [5, 6].

In Uttarakhand, B. persicum is primarily cultivated in its typical form without any officially recognized distinct varieties [6]. Differences can be caused by environmental factors such as altitude, microclimate conditions, and soil type, these differences do not classify them as separate species. Due to its niche-specific characteristics, the state of Himachal Pradesh has granted B. persicum geographical indication (GI) protection under GI number 432, recognizing its unique geographical and botanical attributes (Table 1).

One of the major limitations to the commercial cultivation of B. persicum is its extended life cycle. The plant’s slow growth and long maturation period have deterred widespread farming, contributing to a decline in its cultivation. Consequently, the species is facing a concerning depletion in its natural habitats, leading to its inclusion in the list of endangered species [8, 9].

B. persicum is often mistakenly known as Nigella sativa or Carum carvi, however, it has been the focus of extensive phytochemical studies. The seed and fruit extracts of B. persicum have demonstrated a variety of bioactive properties, including antimicrobial, antioxidant, anti-inflammatory, and antidiabetic effects. This positions the plant as a potential natural antioxidant and preservative for application in various food systems [10, 11].

Although previous reviews have covered the medicinal properties of B. persicum, this review aims to provide a comprehensive, updated analysis of its morphological, biochemical, and molecular characteristics [12]. Additionally, it explores its phytochemical profile, novel food applications, and therapeutic potential, offering valuable insights for consumers, as well as the food and pharmaceutical industries. The review also highlights critical areas requiring policy intervention to ensure the conservation and sustainable use of this valuable species [13, 14].

Ethnobotanical knowledge

B. persicum belongs to the family Apiaceae or Umbelliferae. Apiaceae family consists of 423 genera, which are herbs, shrubs, trees, and some aromatics. Bunium consist of 166 species. B. persicum is a perennial herbaceous geophyte that generally grows to a height of 30–40 cm [15]. This plant grows primarily in high-altitude regions and is a geophyte, meaning it stores nutrients in underground structures such as tubers, allowing it to survive harsh environmental conditions [16]. The stems are hollow between the nodes and house secretory vessels that produce oils and resins. The plant’s inflorescence, part of the Apiaceae family, consists of a single, convex, or flat-topped flower head. The roots and seeds are used as spices that provide flavor for the food. It is used in a way that gives taste to food. These brown fruits are round in shape and hot in taste [17].

Traditional uses of B. persicum

B. persicum seeds are traditionally used in the treatment of digestive problems and urinary problems, and are well recognized in Iranian folk medicine for their diarrhea-relief, respiratory aid, anti-parasitic, and analgesic (anti-nociceptive) properties [18]. The fruits of B. persicum are also traditionally employed to treat flatulence, spasms, menstrual pain, and infections due to their antimicrobial effects. However, their use in pregnant women is strictly limited as they may induce abortion [19].

In Kashmir (India), B. persicum is used as an alternative to Carum carvi (Caraway), which is commonly used to treat menstrual disorders, anorexia, skin conditions, and leucorrhoea. The literature also highlights various therapeutic uses of its seeds, such as antispasmodic and anti-epileptic effects, as well as promoting lactation and lowering blood lipids and lipid levels [20, 21].

In the remote areas of Jammu and Kashmir, and Uttarakhand (India), B. persicum seeds are traditionally used to treat diarrhea, indigestion, and dysentery. Additionally, its fruits are considered effective in treating hematomas, dysuria, kidney stones, and hiccups, and are utilized for managing obesity and digestive issues [22]. The fruits are valued for their role as flavoring agents, galactagogues, carminatives, calmatives, and appetite stimulants (Table 2).

Nutritional potential of B. persicum

B. persicum presents a diverse and rich nutritional profile, making it an important food ingredient with potential health benefits. Its moderate carbohydrate content, essential fatty acids, mineral richness, and the presence of vital vitamins, amino acids, and fibers make it a valuable addition to a balanced diet. Regular consumption of black cumin could contribute to improved cardiovascular health, digestive function, immune response, and overall well-being, especially when used in conjunction with other healthy dietary habits [30–35].

• 1.

  Carbohydrates (35–40%): B. persicum is moderately rich in carbohydrates, which contribute to its energy value. Carbohydrates found in black cumin consist of polysaccharides and simple sugars, which provide a quick source of energy, e.g., glucose, fructose.

• 2.

  Fatty acids (10–12%): Though B. persicum is not particularly high in fats, the seeds contain essential fatty acids. The presence of unsaturated fatty acids makes black cumin oil a valuable addition to the diet, contributing to the regulation of lipid metabolism and maintaining healthy cholesterol levels, e.g., linoleic acid, oleic acid.

• 3.

  Minerals: B. persicum is an excellent source of various essential minerals, including:

  • Iron (3–5%)

  • Calcium (6–9%)

  • Magnesium (2–4%)

  • Potassium (2–5%)

  • Phosphorus (1–3%)

• 4.

  Vitamins: The seeds of B. persicum are packed with vitamins, especially those with antioxidant properties. Key vitamins include:

  • Vitamin C

  • Vitamin A

  • B-vitamins (B1, B2, and B3)

• 5.

  Amino acids: Black cumin seeds are an important source of amino acids, including essential ones that the body cannot synthesize. These include lysine, methionine, tryptophan, and phenylalanine, which are crucial for protein synthesis, tissue repair, and various metabolic processes.

• 6.

  Dietary fibers (20–25%): The fiber content in B. persicum is substantial, which plays an important role in digestive health. The seeds contain both soluble and insoluble fibers:

  • Soluble fiber helps regulate blood sugar levels and reduce cholesterol by absorbing water in the digestive tract.

  • Insoluble fiber contributes to bowel regularity, preventing constipation and promoting healthy gut bacteria growth.

Dietary fiber also has a prebiotic effect, fostering the growth of beneficial bacteria in the gut, which in turn supports better digestion and nutrient absorption.

Bioactive potential of B. persicum

Bioactive compounds found in B. persicum contribute significantly to its medicinal and therapeutic properties. These compounds are responsible for various biological activities (Table 3) [36–39].

• 1.

  Antioxidant activity: The seeds are rich in phenolic compounds and flavonoids, both of which are potent antioxidants. These compounds play a key role in scavenging free radicals, reducing oxidative stress, and preventing cellular damage caused by oxidative reactions. The high antioxidant activity makes black cumin a promising agent for preventing degenerative diseases, including cancer, cardiovascular diseases, and neurodegenerative conditions like Alzheimer’s.

  • Phenolic compounds such as quercetin, kaempferol, and other flavonoids are the major contributors to the antioxidant profile.

• 2.

  Antimicrobial and antifungal activity: B. persicum has demonstrated significant antimicrobial properties, making it an effective agent against a broad spectrum of bacteria, fungi, and even some viruses. The essential oils (EOs) and extracts of black cumin seeds have been found to exhibit strong inhibitory effects against pathogenic microorganisms, such as Escherichia coli, Staphylococcus aureus, Candida albicans, and Aspergillus niger.

  • Thymol and carvacrol, key components of B. persicum EOs, are primarily responsible for its antimicrobial activity. These bioactive compounds disrupt microbial cell membranes, leading to the inhibition of their growth and proliferation.

• 3.

  Anti-inflammatory properties: Chronic inflammation is linked to numerous diseases, including arthritis, cardiovascular disorders, and cancer. B. persicum has been shown to have strong anti-inflammatory activity. This is associated with the presence of compounds such as flavonoids and terpenoids, which inhibit the production of pro-inflammatory substances such as prostaglandins and cytokines.

  • Terpenes like p-cymene and β-pinene found in black cumin oil have shown significant effects in reducing inflammatory responses, making it a useful agent in managing inflammatory conditions.

• 4.

  Anti-carcinogenic and anti-tumor activity: In vitro studies have suggested that extracts from black cumin seeds suppress the growth of cancer cells and trigger apoptosis (programmed cell death) in multiple cancer cell lines, including colon and breast cancer cells.

  • Thymoquinone, a bioactive compound present in B. persicum, is especially noted for its anti-tumor properties.

• 5.

  Gastroprotective activity: The bioactive compounds in B. persicum also contribute to its gastroprotective properties. Traditional medicine has used black cumin to treat various gastrointestinal disorders such as indigestion, bloating, and stomach ulcers.

  • EOs in the seeds have been shown to possess anti-ulcer activity, potentially offering protection against conditions like gastric ulcers induced by stress or medication [such as non-steroidal anti-inflammatory drugs (NSAIDs)].

• 6.

  Cardioprotective effects: Cardiovascular health can benefit significantly from the bioactive components in B. persicum. Studies indicate that the antioxidant and anti-inflammatory compounds in black cumin help improve lipid profiles by lowering low-density lipoprotein (LDL) and increasing high-density lipoprotein (HDL).

  • Flavonoids and polyphenolic compounds found in black cumin seeds are key players in enhancing cardiovascular protection by reducing oxidative stress and inflammation that can damage heart tissues.

• 7.

  Anti-diabetic and metabolic benefits: Several studies have demonstrated that B. persicum has potential anti-diabetic effects by improving insulin sensitivity and reducing blood sugar levels. The seed extract appears to help regulate glucose metabolism and may offer therapeutic benefits for individuals with type 2 diabetes.

  • Flavonoids and other bioactive compounds in black cumin appear to influence glucose uptake and insulin secretion, making it a promising supplement for managing diabetes and related metabolic disorders.

• 8.

  Neuroprotective potential: Emerging research suggests that B. persicum may possess neuroprotective properties due to its high antioxidant content by reducing oxidative damage and inflammation in neural tissues. Although, some of the bioactive compounds in black cumin seeds have shown potential for improving memory and cognitive function, making it a promising natural agent for supporting brain health.

Table 3.

The main bioactive components of the Bunium persicum extract/essential oil and their structures (https://pubchem.ncbi.nlm.nih.gov/)

S.No.	Compound name	GC-MS data (%)	Compound structure	PubChem CID	References
1	Cuminaldehyde	27.80–5.96		326	[40]
2	γ-Terpinene	19.20–10.50		7461	[41]
3	γ-Terpinene-7-al	19.20–9.40		6429112	[42]
4	p-Cymene	15.90–4.31		7463	[43]
5	Limonene	48.40–4.42		22311	[44]
6	Carvone	78.80–23.30		7439	[45]
7	α-Pinene	11.27–2.37		6654	[46]
8	α-Terpinene	11.13–7.30		7462	[47]
9	Germacrene D	16.20		5317570	[48]
10	cis-Limonene oxide	1.80		6857487	[49]
11	trans-Carveol	1.30		94221	[50]
12	Menthone	1.20		26447	[51]
13	Bornyl acetate	2.90		93009	[52]
14	trans-Dihydrocarvone	14		6432474	[53]

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Recent GC-MS analyses have identified novel bioactive constituents in B. persicum EOs, such as dihydrocarvone and bornyl acetate, which show promising anti-inflammatory and antimicrobial activities [54].

Discussion

The present review summarizes the ethnobotanical uses, phytochemical composition, and medicinal properties of B. persicum. The traditional uses of its seeds, roots, and EOs are corroborated by modern scientific evidence, highlighting its therapeutic potential [54].

This plant is used in treating a wide range of conditions, including neurological disorders, gastrointestinal diseases, respiratory issues, cardiovascular dysfunctions, microbial infections, and urinary tract diseases.

Furthermore, its beneficial effects in diabetes management are supported by its antioxidant, hypoglycemic, antihyperlipidemic, α-amylase inhibitory, and insulin secretion-enhancing activities. Advances in molecular studies have elucidated the mechanisms through which B. persicum compounds modulate inflammatory pathways and cellular oxidative stress [55].

Moreover, the integration of B. persicum into functional foods and nutraceuticals has been gaining traction due to its broad spectrum of health benefits. This dual role in enhancing food safety and delivering therapeutic benefits positions B. persicum as a valuable ingredient in the functional food industry.

The antimicrobial properties of B. persicum are driven by key secondary metabolites such as thymol and carvacrol. These terpenoids disrupt microbial cell membranes, leading to growth inhibition of pathogens such as Escherichia coli and Staphylococcus aureus. These findings align with the observed traditional use of B. persicum in treating infections and preserving food products. However, the variability in antimicrobial activity across different plant populations underscores the influence of environmental and genetic factors on phytochemical composition [56].

In a present study, the methanolic extracts of B. persicum were found to have 683 anti-inflammatory effects by blocking albumin denaturation that contributes to the 684-inflammation process [57]. The EO was obtained from leaves and its constituents were identified using GC-MS analysis. Then, the antifungal ability of the EO and its main constituents against Colletotrichum lindemuthianum was investigated using in vitro and in vivo assays. The effects of the EO and its main constituents on cell wall degrading enzymes (CWDEs) activity such as pectinase, cellulase, and xylanase, as well as part of the mechanisms involved in the infection process of this fungus, were demonstrated. On the other hand, the anti-glycation potential of polyphenol-rich plant extracts has been shown previously and B. persicum has been demonstrated to possess a high level of polyphenols; so, B. persicum hydroalcoholic extract has a good effect on diabetic disease. Moreover, the abortive property might be due to estrogenic and uterine tonic activities.

Phenolic compounds, including caffeic acid and p-coumaric acid, are identified as key contributors to antioxidant and anti-tyrosinase activities. Flavonoids are noted for their roles in providing antioxidant, anti-diabetic, analgesic, anti-inflammatory, and antiulcerogenic effects. Additionally, terpenoids such as p-cymene and γ-terpinene demonstrate analgesic and antimicrobial properties. Cuminaldehyde is associated with various biological functions, while alkaloids exhibit potential anti-hemotoxic effects.

The selection of desired genotypic traits can enhance the efficiency and productivity of species while ensuring their preservation for future generations, particularly as human activities increasingly threaten overall genetic diversity [58].

Recent studies have identified promising antioxidant, anti-inflammatory, and antimicrobial properties in B. persicum, positioning it as a potential candidate for developing natural therapeutics. The plant’s bioactive compounds have shown efficacy in managing metabolic disorders, such as diabetes and hyperlipidemia, which are of growing concern in modern healthcare.

Conclusion

B. persicum is a highly valued spice and medicinal plant, recognized for its rich phytochemical composition and diverse bioactive properties. It holds significant promise in traditional and modern medicine, with applications ranging from antimicrobial to metabolic disorder management. Further research and sustainable cultivation practices are essential to preserve its therapeutic potential and promote its integration into functional foods and nutraceuticals.