Lotus flower (Nelumbium speciosum)

The lotus flower, Nelumbium speciosum, now generally assigned to the genus Nelumbo, is one of the most extensively studied aquatic plants for its botanical, ecological, and health-related relevance. Belonging to the family Nelumbonaceae, it exhibits a highly specialized biological structure, with fleshy rhizomes anchored deeply in the sediment and large, peltate leaves with a markedly hydrophobic surface. These leaves have inspired research on the well-known “lotus effect”, a self-cleaning phenomenon that has become a model for various technological and biomimetic applications, including materials science and surface engineering.

The flower itself, characterized by a remarkable chromatic variability and a complex floral morphology, shows a very rare feature among angiosperms: thermoregulation of the floral receptacle. Through this process, the internal temperature of the flower can remain relatively constant even when ambient conditions fluctuate. This phenomenon has been the subject of biothermal studies aiming to clarify the mechanisms of energy dissipation and heat production in plants, and it is often cited as an example of refined physiological adaptation in the plant kingdom.

From a health perspective, the lotus flower is gaining increasing attention because of its bioactive compounds, which are distributed in different parts of the plant, especially in the seeds, petals, leaves, and rhizomes. The seeds, known both for their exceptional longevity and their biochemical stability, contain alkaloids, flavonoids, amino acids, and other phytochemicals that are actively investigated in nutraceutical research. The leaves, traditionally used in infusions and decoctions, have been studied for their content of antioxidant molecules, with potential roles in counteracting oxidative processes and supporting physiological responses to metabolic stress.

The rhizomes, rich in starch and various phenolic compounds, are examined for both their energy contribution and their possible functional properties related to the modulation of carbohydrate metabolism. In some dietary contexts, they are considered a source of complex carbohydrates and fiber, which may contribute to satiety and glycemic balance when consumed as part of a balanced diet. The petals, due to their flavonoid content, are also investigated for possible antioxidant activity and for their role in cellular protection mechanisms.

Although many of these potential health benefits are still being evaluated and require confirmation through rigorous clinical studies, the lotus is increasingly positioned as a plant of interest in the field of phytotherapy and functional foods. Its traditional use in Asian medical systems provides a historical and empirical framework, while modern research aims to clarify mechanisms of action, safety profiles, and the most appropriate forms and doses for human use. Any application for health purposes should remain within the scope of regulated practices and evidence-based approaches, avoiding extrapolation from preliminary or purely experimental data.

From an ecological standpoint, the lotus flower contributes significantly to the structure and functioning of aquatic ecosystems in which it grows. Its leaves and stems help create complex microhabitats that support invertebrates, fish, and other organisms, while the dense rhizome network promotes sediment consolidation and reduces erosion. These ecological roles make the species particularly relevant in discussions on habitat restoration and the management of shallow water bodies.

Finally, the cultural and symbolic significance of the lotus—deeply rooted in various Asian religious and philosophical traditions—has favored a long history of domestication and cultivation. This cultural dimension has indirectly stimulated scientific interest, ensuring a broader availability of plant material for biochemical, nutritional, and phytotherapeutic studies. The intersection between scientific, cultural, and health-related aspects makes the lotus flower a plant of enduring and multidisciplinary academic interest.

Botanical classification (APG IV system)

Indicative nutritional values per 100 g (dried lotus seeds from Nelumbo nucifera)
Values refer to dried lotus seeds and may vary with variety, growing conditions and drying process.

At typical serving sizes (around 20–30 g of dried seeds as a snack or ingredient), lotus seeds provide a meaningful caloric and protein contribution, while total fat intake remains moderate.

Lipid profile note

The overall fat content of dried lotus seeds is low, and most of the energy comes from carbohydrates and proteins. Within the lipid fraction, saturated fatty acids (SFA) are present only in small amounts; when they predominate over unsaturated fats in the overall diet, they are generally considered less favourable for cardiovascular health. Monounsaturated fatty acids (MUFA) are usually regarded as more beneficial when they replace SFA in the diet. Polyunsaturated fatty acids (PUFA), including both omega-6 and omega-3, are important for cell membrane structure and for the modulation of inflammatory processes.

In lotus seeds the absolute amounts of SFA, MUFA and PUFA are modest, but their qualitative balance is more favourable than that of foods rich in saturated fats.

Plant Characteristics

Nelumbium speciosum is a robust aquatic plant with distinctive features:

• Leaves: Large, circular leaves that can grow up to 60 cm in diameter, often standing above the water surface on long stalks. The leaves are water-repellent, showcasing a "lotus effect" that keeps them clean.
• Flowers: Fragrant and showy, with petals in hues of pink or white, and a bright yellow receptacle at the center. Flowers bloom in summer and can reach 20 cm in diameter.
• Seeds and Rhizomes: The seeds are enclosed in a unique, perforated receptacle, while the rhizomes are long, tuberous, and submerged in mud.

Chemical Composition and Structure

The lotus plant is rich in bioactive compounds, contributing to its medicinal and nutritional value:

• Flavonoids: Quercetin, kaempferol, and isoquercitrin, which have antioxidant and anti-inflammatory properties.
• Alkaloids: Including nuciferine, which exhibits sedative and calming effects.
• Polysaccharides: Found in seeds and rhizomes, these compounds support immune health and provide energy.
• Vitamins: Particularly vitamin C, contributing to its antioxidant effects.
• Minerals: Rich in potassium, magnesium, and calcium, which support overall health.

How to Cultivate Nelumbium speciosum

Cultivating Nelumbium speciosum requires an aquatic environment and specific conditions:

1. Climate: Prefers warm, tropical, or subtropical climates with full sun. It is frost-sensitive and thrives in water temperatures between 20–30°C.
2. Water Requirements: Grows in shallow, still, or slow-moving water, typically 30–60 cm deep.
3. Soil: Requires heavy, clay-rich soil submerged in water to anchor its rhizomes.
4. Propagation: Propagated by seeds or rhizome division. Seeds should be scarified and soaked before planting, while rhizomes are planted directly in submerged soil.
5. Maintenance: Requires minimal care once established. Regular removal of decayed leaves and flowers promotes healthy growth.

Uses and Benefits

The sacred lotus has diverse applications in traditional medicine, cuisine, and spirituality:

• Culinary Uses:

  • Seeds: Consumed raw, roasted, or ground into flour, they are rich in nutrients.
  • Rhizomes: Used in Asian cuisines, often stir-fried, pickled, or added to soups.
  • Petals and Leaves: Occasionally used as food wraps or in herbal teas.

• Medicinal Benefits:

  • Digestive Health: The rhizomes aid in digestion and help alleviate constipation.
  • Calming Effects: The alkaloids provide sedative properties, helping with anxiety and sleep disorders.
  • Anti-inflammatory and Antioxidant: Flavonoids and phenolic compounds combat oxidative stress and inflammation.
  • Cardiovascular Health: Potassium and magnesium in the seeds and rhizomes support heart health and regulate blood pressure.

• Spiritual Significance: Symbolizing purity and enlightenment, the lotus is a sacred emblem in Buddhism and Hinduism.

Applications

• Medical: Used in traditional remedies to treat digestive issues, inflammation, and insomnia. The seeds and leaves are commonly prepared as teas or powders.
• Cosmetic: Lotus extracts are incorporated into skincare products for their hydrating, antioxidant, and soothing properties.
• Culinary: The seeds, rhizomes, and flowers are used in various Asian dishes and beverages.
• Ornamental: Cultivated in water gardens and ponds for its beauty and ecological benefits.

Environmental and Safety Considerations

Nelumbium speciosum is an environmentally friendly plant that improves water quality by oxygenating the water and providing habitat for aquatic life. It is generally safe for consumption, though overconsumption of seeds or rhizomes may lead to mild digestive discomfort. Cultivation should be managed to prevent invasive tendencies in non-native regions. As with any plant product, individuals with allergies should use caution.

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References__________________________________________________________________________

Ushimaru T, Kanematsu S, Katayama M, Tsuji H. Antioxidative enzymes in seedlings of Nelumbo nucifera germinated under water. Physiol Plant. 2001 May;112(1):39-46. doi: 10.1034/j.1399-3054.2001.1120106.x. 

Abstract. Dry seeds of anoxia-tolerant lotus (Nelumbo nucifera Gaertn=Nelumbium speciosum Willd.) have green shoots with plastids containing chlorophyll, so photosynthesis starts even in seedlings germinated under water, namely hypoxia. Here we investigated antioxidative enzyme changes in N. nucifera seedlings responding to oxygen deficiency. The activity of superoxide dismutase (SOD; EC 1.15.1.1), dehydroascorbate reductase (DHAR; EC 1.8.5.1) and glutathione reductase (GR; EC 1.6.4.2) were lower in seedlings germinated under water (submerged condition) in darkness (SD seedlings) than those found in seedlings germinated in air and darkness (AD seedlings). In contrast, ascorbate peroxidase (APX; EC 1.11.1.11) activity was higher in SD seedlings and the activity of catalase (EC 1.11.1.6) and monodehydroascorbate reductase (MDAR; EC 1.6.5.4) in SD seedlings was nearly the same as in AD seedlings. When SD seedlings were exposed to air, the activity of SOD, DHAR and GR increased, while the activity of catalase and MDAR decreased. Seven electrophoretically distinct SOD isozymes were detectable in N. nucifera. The levels of plastidic Cu,Zn-SODs and Fe-SOD in SD seedlings were comparable with those found in AD seedlings, which may reflect the maintenance of green plastids in SD seedlings as well as in AD seedlings. These results were substantially different from those previously found in rice seedlings germinated under water.

Bashir S, Sial RN, Ashraf MU, Mushtaq MN, Adnan MA, Erum A. Phytochemical analysis and antimicrobial activity of aqueous and methanolic extracts of the flowers of Nelumbium speciosum. Pak J Pharm Sci. 2018 Nov;31(6):2429-2434. 

Abstract. In present investigation aqueous and methanolic extracts of Nelumbium speciosum flowers were screened for phytochemical constituents and antibacterial activity to ascertain their traditional use. Antimicrobial activity of both extracts was tested by Kirby-Bauer disc diffusion method against four Gram positive strains, viz. Staphylococcus aureus (ATCC25923), Streptococcus agalactiae (13813), Bacillus subtilis (ATCC 6633), Staphylococcus epidermidis (ATCC 12228) and four Gram negative bacterial strains Escherichia coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 27853), Proteus mirabilis (12453) and Klebsiella pneumoniae (10031). Phytochemical analysis showed the presence of tannins, saponins and alkaloids in both extracts while flavonoids and steroids were present only in methanolic extract. Methanolic extract of Nelumbium speciosum flower showed concentration dependent antibacterial activity against all tested strains with maximum zone of inhibition (17.3±0.3mm) against P. aeruginosa. Aqueous extract showed concentration dependent activity against S. aureus, E. coli, B. subtilis and S. epidermidis with maximum antibacterial activity against E. coli (14.3±0.3mm). MIC of methanolic and aqueous extracts was in the range of 0.015-0.251 and 0.0625-0.251 mg/mL, respectively. Results showed that methanolic extract of Nelumbium speciosum exhibits superior antibacterial activity than aqueous extract.