Potential Underexploited Vegetable Crops of Tamil Nadu with Emphasis on Nutritional and Medicinal Value

Underutilized vegetable crops represent a vital yet often neglected segment of agro-biodiversity, offering considerable potential to enhance nutritional security, sustainable agriculture, and resilience to climate change. Tamil Nadu, with its varied agro-climatic zones spanning coastal plains, dry regions, and hilly terrains, supports a rich array of indigenous and lesser-known vegetables adapted to local conditions. This review critically explores the potential of underexploited vegetable crops in the region, focusing on their nutritional and medicinal attributes. It covers leguminous vegetables, cucurbits, tubers, leafy greens, and fruit vegetables, emphasizing their protein, essential mineral, vitamin, antioxidant, and bioactive compound content. These crops exhibit multiple health-promoting properties, including antidiabetic, antioxidant, anti-inflammatory, antimicrobial, and cardioprotective effects. Despite their demonstrated benefits, these vegetables remain marginal due to limited research, weak seed systems, low market integration, and poor consumer awareness. The review also highlights significant constraints and proposes strategies for conservation, crop improvement, value addition, and policy support. Enhancing their cultivation and utilization can strengthen dietary diversity, conserve genetic resources, and promote sustainable nutrition and livelihoods in Tamil Nadu.

DOI

https://doi.org/10.29321/MAJ.10.261269

Pages

114 - 126

Creative Commons

Copyright

© The Author(s), 2026. Published by Madras Agricultural Students' Union in Madras Agricultural Journal (MAJ). This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited by the user.

Keywords

Underutilized vegetables Agro-biodiversity Nutritional value Medicinal properties Climate resilience Tamil Nadu

Introduction

Vegetables are indispensable components of the human diet, serving as primary sources of essential vitamins, minerals, dietary fibre, and a wide range of bioactive compounds necessary for maintaining health and preventing malnutrition (Ramkumar et al., 2025). Adequate intake of vegetables plays a crucial role in addressing micronutrient deficiencies, strengthening immune function, and reducing the risk of non-communicable diseases. In a populous country like India, where food demand continues to rise alongside persistent nutritional imbalances, vegetables contribute significantly to nutritional and food security by ensuring dietary diversity, affordability, and year-round availability (Harris et al., 2022).

Despite India’s remarkable progress in vegetable production, the benefits are primarily derived from a limited number of major commercial crops. A substantial proportion of edible plant diversity remains outside mainstream agriculture. These crops are commonly referred to as underutilized, neglected, minor, or orphan vegetables (Peduruhewa et al., 2021). Underutilized or neglected vegetable crops are plant species with a history of traditional use for food and medicine but that are inadequately researched, poorly commercialized, and weakly integrated into formal seed systems, markets, and policy frameworks. Although they are often locally or regionally important, their potential remains untapped mainly at the national and global levels.

Underutilized vegetables are gaining renewed attention amid climate change and sustainable agriculture. Many of these crops possess inherent tolerance to drought, heat, poor soils, and biotic stresses, require fewer external inputs, and thrive under marginal conditions (Pandiyaraj et al., 2024). Their cultivation can enhance agrobiodiversity, improve ecosystem stability, reduce reliance on a narrow crop base, and support climate-resilient, low-input farming systems, while simultaneously contributing to nutritional and livelihood security (Debbarma et al., 2020).

Tamil Nadu represents a notable hotspot of agro-biodiversity in India, characterized by diverse agro-climatic zones ranging from coastal plains and dry tracts to hill ecosystems. This diversity supports a wide array of indigenous and lesser-known vegetable crops, including leafy greens, tubers, legumes, gourds, and perennial vegetables that are deeply embedded in local food cultures and traditional knowledge systems (Karthick et al., 2024).

In this context, the present review aims to critically document the potential underexploited vegetable crops of Tamil Nadu, with particular emphasis on their nutritional composition and medicinal properties. The review highlights their ecological resilience, traditional relevance, and potential for conservation and broader use in strengthening sustainable agriculture and nutritional security.

Methodology

Agro-Climatic Diversity of Tamil Nadu

Tamil Nadu exhibits considerable agro-climatic diversity, ranging from the humid coastal plains and fertile river basins to semi-arid interiors and cool hill ecosystems, which collectively favour the cultivation of a wide range of underutilized vegetable crops. Variations in rainfall (monsoonal dependence), temperature regimes, soil types, and altitude enable the successful growth of indigenous leafy vegetables, tubers, legumes, gourds, and perennial vegetables adapted to marginal and low-input conditions. This ecological heterogeneity supports rich vegetable diversity and provides opportunities to promote climate-resilient, nutritionally important underexploited crops across the state's different farming systems (Government of Tamil Nadu, 2020).

Criteria for categorizing vegetables as underutilized

To qualify as an underutilized vegetable crop, a plant generally exhibits the following characteristics (Thakur, 2014):

· Its edibility is well established through scientific studies or long-standing ethnobotanical knowledge.

· The crop has a history of cultivation, either historically or within restricted geographical regions rather than widespread commercial areas.

· Present-day cultivation and consumption levels are substantially lower when compared with commonly grown conventional vegetables.

· Organized systems for seed production, certification, and distribution are poorly developed or absent.

· The crop is closely associated with traditional, indigenous, or community-specific uses in certain localities.

· It has attracted minimal focus from agricultural research programs, extension networks, farmers, policy planners, and technology developers.

· Despite limited recognition, the crop often possesses superior nutritional value, medicinal or therapeutic benefits, and/or multiple functional uses, underscoring its untapped potential.

Results Discussion

Nutritional and Medicinal Properties of Diverse Underutilized Vegetables of Tamil Nadu

a) Underutilized Leguminous Vegetables

Underutilized leguminous vegetables represent a diverse group of nutrient-rich crops with high agronomic, nutritional, and medicinal potential that remain inadequately exploited in mainstream food and farming systems (Figure 1).

1. Faba bean. Faba bean (Vicia faba L.; Fabaceae), commonly referred to as broad bean, Windsor bean, winter bean, or bakla bean, is a minor legume vegetable cultivated mainly in the hilly regions of India. It is used for human consumption, animal feed, and as green manure, improving soil fertility through biological nitrogen fixation (Jensen et al., 2010). In the Nilgiris district of Tamil Nadu, broad beans are consumed as fresh seeds, tender pods, or dried seeds, and despite being underutilised, they fetch reasonable market prices (Raja et al., 2023; Raja et al., 2025). Faba bean is nutritionally rich, with high protein (29.4%) and carbohydrates (51-68%) and low fat (1.5%); 100 g of seeds provides protein (4.5 g), carbohydrates (7.2 g), vitamin C (12.0 mg), calcium (50 mg), and iron (1.4 mg). At the same time, the green pods and leaves contain bioactive phytochemicals (Akgun and Canci, 2023). Faba bean contains flavonoids with antioxidant, antiviral, anticancer, anti-inflammatory, and anti-atherosclerotic effects, and L-DOPA, a dopamine precursor used in Parkinson’s disease therapy (Debnath et al., 2025).

2. Winged bean. Winged bean (Psophocarpus tetragonolobus (L.) DC.; Fabaceae) is an underutilized, self-pollinated tropical legume of Southeast Asian or Papua New Guinea origin, valued for its climate adaptability, high nutritional quality, strong nitrogen fixation, multiple edible parts, and processing potential (Paliwal et al., 2020). Winged bean is known as a “supermarket on a stalk” because all its plant parts are edible, and its soybean-like nutritional value earns it the nickname “soybean of the tropics” (Khan, 1976). Winged bean is a nutrient-dense legume with seeds high in protein (29–37%), oil (15–20%), amino acids, vitamins, and minerals, and protein-rich leaves and tubers (12–20%) comparable to those of soybean (Tribhuvan et al., 2024). Winged bean has notable medicinal value, as its high niacin content helps lower cardiovascular risk and its bioactive compounds support traditional therapeutic and cosmetic uses.

3. Cluster bean. Cluster bean (Cyamopsis tetragonoloba (L.) Taub.; Fabaceae), a drought-tolerant multipurpose legume commonly known as guar, is native to India, the world’s leading producer which accounts for about 75% of global production. The tender immature pods used as vegetables are nutrient rich, containing moisture (81%), energy (16 kcal), carbohydrates (10.8 g), protein (3.2 g), fat (1.4 g), vitamin C (49 mg), vitamin A (65.3 IU), calcium (57 mg), and iron (4.5 mg) per 100 g of fresh edible portion (Manivannan et al., 2016). Cluster bean possesses substantial medicinal value due to its guar gum–rich soluble fibre and bioactive compounds, which exhibit cholesterol-lowering, anti-diabetic, anti-inflammatory, antioxidant, digestive, and chemo-preventive properties (Hussain and Mahajan, 2025).

4. Dolichos bean. Dolichos bean (Lablab purpureus L.; Fabaceae), also known as hyacinth bean, is a versatile, climate-smart legume cultivated across continents, valued for its adaptability, protein richness, and diverse uses in farming systems and cuisines. Dolichos lablab leaves contain up to 28% protein, 150–157 mg iron, and 25–35 mg zinc per 100 g. It shows antidiabetic, antioxidant (DPPH IC₅₀: 430-853 µg/mL), antimicrobial, and anti-inflammatory activities due to flavonoids and polyphenols (Chetia et al., 2025).

5. Clove bean. Clove bean (Ipomoea muricata (L.) Jacq.; Convolvulaceae) is an underexploited vegetable cultivated for its fruits and thickened pedicels, widely adapted from sea level to about 1700 m altitude. Clove bean is nutritionally rich, providing dietary fibre, protein (1.00–1.50 g/100 g), calcium (200–220 mg/100 g), phosphorus (120–150 mg/100 g), iron (0.13–0.19 mg/100 g), ascorbic acid (30–40 mg/100 g), and crude fibre (0.67–3.33%). Clove bean has medicinal importance, as indolizidine alkaloids present in its seeds, leaves, and stems impart analgesic, antiseptic, and wound-healing properties (James and Girija, 2025).

6. Yard-long bean. Yard long bean (Vigna unguiculata subsp. Sesquipedalis; Fabaceae) is an underutilized, nutritionally rich cowpea type, characterized by cleistogamous self-pollination, and very long pods (0.5–1 m) bearing 8–12 mm seeds. It is also called asparagus bean, snake bean, Chinese long bean, or pea-bean, and is cultivated mainly for its crisp, tender pods, which are consumed fresh or cooked. Tender pods are called the “poor man’s meat,” providing 24–27% low-fat protein along with calcium (72 mg), phosphorus (59 mg), iron (2.5 mg), carotene (564 µg), thiamine (0.07 mg), riboflavin (0.09 mg), and vitamin C (24 mg) per 100 g (Jayasinghe et al., 2015).

7. Sword bean. Sword bean (Canavalia gladiata Jacq.; Fabaceae) is a warm-season, self-pollinated, climbing legume with long, fleshy, sword-like pods, widely grown in South and Southeast Asia. The seeds are low in fat, high in protein, rich in antioxidant phenolics, and used in traditional medicine for cough, kidney pain, and other ailments (Qian et al., 2025).

8. Jack bean. Jack bean (Canavalia ensiformis; Fabaceae) is a tropical legume tolerant of acidic and dry soils, highly drought-resistant, with deep roots that support its cultivation. It is the richest source of protein (23–34%) and carbohydrates (55%). This legume contains nutrients that offer health benefits, including protection against cancer, heart disease, and diabetes, as well as support for healthy aging (Shevkani et al., 2022).

Figure 1. Underutilized Leguminous Vegetables

b) Underutilized Cucurbitous Vegetables

Underutilized cucurbitous vegetables are lesser-known climbing or trailing members of the Cucurbitaceae family, typically grown as warm-season crops, valued for their nutritional and medicinal properties, yet remain under-cultivated with limited commercial presence in Tamil Nadu (Figure 2).

1. Momordica sp. Vegetables. Momordica includes 59 species, primarily annual and perennial climbing or herbaceous plants, with a few small shrubs; they are distributed worldwide, with 47 species in Africa and 12 in Australia and Asia (Heneidak and Khalik, 2015).

Table 1. Nutritional and Therapeutic Attributes of underutilized Momordica sp.

Sl. No.	Momordica sp.	Nutritional and Medicinal Value	Reference
1.	Sweet gourd (Momordica cochinchinensis) - Oblong, smooth, tender fruits.	Their young green fruits are cooked as vegetables and are the richest source of vitamins and minerals. Unripe fruits act as an appetizer and astringent, while root juice is stimulant, astringent, and antiseptic, used to control bleeding piles and treat expectorant, urinary, and bowel disorders.	Bora et al. (2025)
2	Spine gourd (Momordica dioica) - Small, oval, spiny, edible fruits.		Bora et al. (2025)
3.	Mithipagal (Momordica charantia var. muricata.) - Small, disc-shaped fruits characterized by numerous surface tubercles.	Mithipagal contains higher levels of protein, fat, carbohydrates, and minerals (iron, calcium, and vitamin C) than large-fruited types. It shows antidiabetic, antioxidant, anti-inflammatory, antimicrobial, anti-HIV, anti-ulcer, anti-leukemic, and antitumor activities.	Agalya et al. (2023)
4.	Athalakkai (Momordica cymbalaria)- Pyriform fruits; small size; 20–25 mm length.	Rich in K (505.9 mg), Ca (73.6 mg), Na (41.6 mg), Fe (1.71 mg), vitamin C (299.1 mg), carotenoids (2.81 mg), and lycopene (1.86 mg) per 100 g. Traditionally used for diabetes, rheumatism, ulcers, skin diseases, and diarrhoea, with antioxidant and anticancer properties.	Chinthan et al. (2021)

2. Ivy gourd. Ivy gourd (Coccinia grandis), also called kundru or tindori, is a highly nutritious vegetable (Moisture 94%, Dietary fibre 1.6 g, Protein 1-2 g, Fat 0.4 g, Carbohydrates 3.1 g, Carotene 156 µg, Vitamin A 260 IU, Vitamin C 28 mg, Iron 14 mg, Energy 18 kcal per 100 g). Daily intake of 100 g helps lower blood sugar, supports bone and immune health, and its tendrils provide essential minerals. Leaf extracts show antimicrobial activity against pathogenic bacteria (Tak et al., 2021).

3. Pointed gourd. Pointed gourd (Trichosanthes dioica), known as Parwal or Pravar and often called “green potato” in India, is valued for its edible fruits and nutritious leaves. The crop is a good source of carbohydrates (4.2g/100g), vitamins A (255 IU/100g) and C (2.5 mg/100g), and essential minerals, and its juice is traditionally used as a tonic for hair loss and mild liver enlargement (Sharma et al., 2023).

4. Chayote. Chayote (Sechium edule) is a perennial climbing cucurbit in which all plant parts are utilized: fruits, tuberous roots, tender leaves, and shoots are consumed as vegetables, and the leaves and peel are traditionally valued for their diuretic properties. It is rich in dietary fibre, vitamin C, potassium, folate (vitamin B9), and antioxidants while being low in calories and fat. Additionally, its high content of polyphenols, flavonoids, and other bioactive compounds contributes to multiple health-promoting effects, including antihypertensive, antimicrobial, antioxidant, anticancer, antihyperglycemic, and neuropharmacological activities (Verma et al., 2017).

5. Round melon. Round melon (Praecitrullus fistulosus), also called tinda, Indian round gourd, apple gourd, or Indian squash, is a cucurbit vegetable with light-green, hairy, spherical fruits (5–8 cm, 45–60 g); tender fruits are eaten as vegetables, and the seeds are roasted. The fruit is rich in proteins and carbohydrates. It possesses cooling, digestive, diuretic, and anti-inflammatory properties and is traditionally used to support digestion, urinary health, and overall metabolic balance (Tyagi et al., 2017).

Figure 2. Underutilized Cucurbitaceous Vegetables

c) Underutilized Tuber Crops

Tamil Nadu harbors several underutilized tuber crops that are nutritionally rich and climate-resilient. These crops have potential for improvement, improving food security, nutrition, and income generation in marginal farming systems (Figure 3).

1. Yams. Yams (Dioscorea spp.; Dioscoreaceae) are tuberous, perennial crops (≈600 species worldwide), with Greater, Lesser, and White yams being the most cultivated for food and medicinal uses. The key nutritional components and bioactive properties of these widely cultivated yam species are summarized in Table 2.

Table 2. Nutritional and medicinal attributes of major yam species

Sl. No.	Dioscorea sp.	Nutritional and Medicinal Value	Reference
1.	Greater yam (D. alata)	Rich in carbohydrates, protein (6–8 g protein/100g), potassium, magnesium, and iron; contains anthocyanins, β-carotene, diosgenin, and dioscorin; exhibits antioxidant, anticancer, anti-inflammatory, and immunomodulatory activities.	Tareen et al. (2025)
2.	Lesser yam (D. esculenta)	Contains carbohydrates, dietary fiber, protein (2.1 g protein/100g), calcium, potassium, and iron; diosgenin provides antioxidant, anti-inflammatory, and anti-diabetic effects; improves muscle quality and glycemic control.	Wang et al. (2025)
3.	White yam (D. rotundata)	High in carbohydrates, moderate protein (1.5 g/100g), iron, potassium; contains diosgenin, flavonoids, phenols; supports antioxidant, digestive, and metabolic health; staple tuber in West Africa.	Alinnor and Akalezi, (2010)

2. Elephant foot yam. Elephant foot yam (Amorphophallus campanulatus; Araceae) has dry, pungent corms with digestive, anthelmintic, and aphrodisiac properties, traditionally used to manage vata–kapha disorders, inflammatory conditions, gastrointestinal ailments, respiratory issues, anaemia, and general debility; fresh corms are also applied externally to relieve acute rheumatism. The corms are rich in minerals, notably iron (340.2), magnesium (119.2), potassium (38.1), copper (32.6), zinc (23.1), and phosphorus (4.53) μg/gm (Srivastava et al., 2014).

3. Taro. Taro (Colocasia esculenta; Araceae) is a perennial, herbaceous tuber crop cultivated worldwide for its starchy edible corms and leaves. It is rich in complex carbohydrates (~70–80% starch), dietary fiber, potassium, calcium, iron, and vitamins; it contains polyphenols and resistant starch with antioxidant, anti-inflammatory, prebiotic, and metabolic health benefits (Kaushal et al., 2015).

4. Chinese potato. Chinese potato (Coleus rotundifolius; Lamiaceae) is a perennial herb native to tropical Africa, grown in India for its edible tubers. The tubers are nutritionally rich, containing reducing sugars (26 mg), protein (13.6–14.6 mg), fiber (1.6%), minerals such as calcium (29 mg) and phosphorus (36 mg), vitamins A (13.6 mg) and C (10.3 mg), B-complex vitamins, and antioxidants per 100 g. The tuber’s aromatic flavour makes it highly desirable, and its flavonoids impart medicinal value by helping reduce blood cholesterol (Murugesan et al., 2020).

Figure 3. Underutilized Tuberous Vegetables

d) Underutilized Leafy Vegetables

Underutilized leafy vegetables of Tamil Nadu represent a diverse group of indigenous greens (Figure 4) that are nutritionally rich and possess valuable bioactive compounds, yet remain largely neglected in mainstream agriculture and diets. Table 3 summarizes the nutritional composition and medicinal properties of selected species, highlighting their potential to improve nutrition, health, and sustainable food systems in the state.