Neem (Azadirachta indica): A Detailed Information

Neem, scientifically known as Azadirachta indica, is a perennial tree with evergreen foliage. Its therapeutic attributes encompass antibacterial, anti-cariogenic, anti-helminthic, anti-diabetic, antioxidant, astringent, antiviral, cytotoxic, and anti-inflammatory properties. Neem finds widespread use in Ayurveda, Unani, and Homeopathic medicine, earning its status as a remarkable tree in contemporary healthcare. Traditionally, it has been employed for addressing inflammation, infections, fevers, skin disorders, and dental issues.

Neem (Azadirachta indica)
Neem (Azadirachta indica)

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Classification and Taxonomic of Neem

DomainEukaryota
KingdomPlantae
PhylumSpermatophyta
SubphylumAngiospermae
ClassDicotyledonae
OrderRutales
Family Meliaceae
Genus Azadirachta
SpeciesAzadirachta indica

Habitat and Distribution of Neem

  • Neem, scientifically known as Azadirachta indica, is believed to have originated in Assam and Burma.
  • It is most extensively used in India, where it grows from the southern tip of Kerala to the Himalayan hills, adapting to various climatic conditions ranging from tropical to subtropical regions and semiarid to wet tropical zones.
  • Over the last century, neem has been introduced to various regions worldwide, including Africa, Fiji, Mauritius, the Caribbean, and Central and South America.
  • The tree has become well-established in at least 30 countries, particularly along the southern fringe of the Sahara.
  • Neem has also been successfully planted in the continental United States, particularly in southern Florida, with exploratory plots established in southern California and Arizona, showcasing its adaptability.
  • Neem prefers areas with disturbed natural vegetation, such as open forests, grasslands, floodplains, riparian zones, and coastal locations. It grows well in both full sun and semi-shade. Although drought-tolerant, it likes dry or damp soil. It can’t withstand being wet or frigid conditions.

Anatomy and Morphology of Neem Plant

Neem Tree
Neem Tree [Image source: ezgrogarden.com]
  • Neem is a medium-sized tree, attaining a height of 15 to 30 meters, featuring a large rounded crown with a diameter ranging from 10 to 20 meters.
  • The tree is predominantly evergreen, although it may shed its leaves during dry seasons, showcasing adaptability to environmental variations.
  • Neem is characterized by a deep taproot and is reliant on mycorrhizal associations for its growth and development.
  • In mature trees, the bark is grey, tends to fissure, and flakes off, while in humid climates, old trees exude a sticky and foetid sap.
  • The branches of neem are numerous and spread widely, contributing to the overall structure of the tree.
  • Its leaves are alternate, petiolated, clustered at the branch ends, and exhibit an unequal pinnate arrangement. They are glabrous, dark glossy green when mature, and measure between 20 to 40 cm in length, bearing 10 to 20 leaflets.
Neem Leaves
  • The leaflets themselves are sickle-shaped, slightly denticulate, and have dimensions of 5 to 10 cm in length and 1.2 to 4 cm in width.
  • Neem produces numerous fragrant white flowers, arranged in large clusters that can reach up to 30 cm in length.
  • The fruits of neem are drupes, measuring 1-2 cm in length, initially smooth and green with white milky juice when unripe, and transitioning to yellow to brown as they mature.
  • The fruits consist of a thin epicarp, a mucilagenous fleshy mesocarp, and a hard endocarp. They enclose a variable number of ovoid oil seeds, each measuring 1-2 cm.
Neem Fruits
Neem Fruits

Growth and Cultivation of Neem Plant

  • Neem is an easily cultivatable tree that can be grown in various locations.
  • Propagation of the neem tree is straightforward, and it can be grown from seeds, seedlings, or saplings, with the option to purchase a sapling from a nursery for convenience.
  • Growing a neem tree from seeds is a viable option, but it requires proper care, considering that the germination property diminishes if seeds are stored for two to six months.
  • The adaptable neem tree can thrive in diverse soil conditions, and it is particularly well-suited for regions with an annual rainfall ranging from 400 to 1200 mm.
  • The fully grown neem tree is typically harvested after 5 to 7 years for its wood or timber, while other parts like leaves, flowers, and fruits can be utilized from a very young age.
  • The neem tree is recognized for its ability to grow in lowland tropics, with optimal performance in areas where annual rainfalls range between 400-1,200 mm.
  • The tree exhibits excellent growth even in dry, infertile sites, outperforming most trees in sterile, stony, or shallow soils.
  • Propagation of the neem tree can be done both sexually and vegetatively, with seeds being the preferred method, either directly on-site or through transplantation of seedlings from a nursery.
  • The preparation of neem seeds is relatively simple, involving the removal of pulp and washing to obtain clean, white seeds.
  • Neem seeds are known for their short viability, and it is recommended to use them fresh as they lose germination capacity after 2-6 months.
  • Growing neem trees from seeds involves planting them in a pot with quality potting mix, covering with an inch of mix, keeping it warm and wet, and waiting for one to three weeks for germination.
  • If starting with a plant, it can be placed in a large container with good potting mix and provided with indirect sunlight until it shows signs of new growth.

Reproduction of Neem Plant

  • Neem (Azadirachta indica) primarily reproduces through seeds.
  • The process involves flowering, pollination, seed development in olive-like drupe fruits, and natural dispersal by animals.
  • Seeds can be collected for artificial propagation in controlled environments, leading to the growth of neem seedlings.
  • Additionally, neem can be propagated vegetatively through methods like cuttings or grafting for specific trait retention.
  • The plant’s natural dispersal by birds and bats contributes to its widespread growth in various environments.

Chemical Composition and Active Components of Neem

Plant PartChemical ConstituentsUses
Seed OilNimbidinAnti-inflammatory, Anti-arthritic, Hypoglycemic, Antipyretic, Spermicidal, Antifungal, Antibacterial, Diuretic.
AzadirachtinAntimalarial
NimbinSpermicidal
NimbolideAntimalarial, Antibacterial
GeduninAntimalarial, Antifungal
MahmoodinAntibacterial
BarkGallic Acid and CatechinAntibacterial
Margolone, Margolonone, and IsomargolononeAntibacterial
LeafCyclic Trisulphide and Cyclic TetrasulphideAntifungal
PolysaccharidesAnti-inflammatory
BarkPolysaccharides G1A, G1BAntitumour
Polysaccharides G2AAnti-inflammatory
NB-2 PeptidogluconImmunomodulatory
LeavesQuercetin (Flavonoid)Antibacterial and antifungal properties.
Nimbosterol (β-Sitosterol)A type of plant sterol.
FlowersEssential Oil (Sesquiterpene Derivatives)Adds fragrance, potential therapeutic uses.
Flavonoids (Kaempferol, Melicitrin)Contribute to the overall chemical profile.
Bark (Trunk)Nimbn (Bitter Principle)Found in trunk bark.
TanninsPresent in both trunk (12-16%) and stem bark (8-11%).
PolysaccharidesAnti-inflammatory polysaccharide in the bark.
GumHydrolyzed Gum (L-arabinose, L-fucose, D-galactose, D-glucuronic acid)Useful in various applications.
SapContains free sugars, amino acids, and organic acids.
HeartwoodCalcium, Potassium, Iron SaltsFound in the heartwood.
Wood Oil (β-Sitosterol, Cycloeucalenol, 24-methylenecycloeartenol)Various components contribute to the chemical complexity.

Uses of Neem Plant

This plant, which is well-known for its therapeutic qualities, has long been used to cure a variety of ailments. The neem plant has many uses, which are listed below:

Medicinal Uses of Neem Plant [Image source: https://doi.org/10.1007/978-981-13-7154-7_17]

Anti-Inflammatory and Anti-Arthritic Properties:

  • Nimbidin, a chemical compound in neem, has demonstrated potential anti-inflammatory and anti-arthritic effects.
  • Inhibits inflammatory actions of macrophages and neutrophils, offering relief from swelling and pain.
  • Suggested use in managing conditions like rheumatoid arthritis, pending further research.

Antiviral, Antibacterial, and Antifungal Applications:

  • Neem exhibits promise in combating viral infections such as dengue fever by impeding virus growth.
  • Demonstrates antibacterial effects, particularly in gum disease and tooth cavities.
  • Potential for managing skin infections, scabies, acne, eczema, and fungal infections like athlete’s foot.

Anti-Cancer Properties:

  • Flavonoids and neem’s chemical components may contribute to inhibiting cancer cell growth.
  • Research indicates potential against skin, breast, lung, oral, stomach, liver, colon, and prostate cancers.

Hypoglycemic Effect for Diabetes:

  • Recent studies explore neem’s potential in lowering blood sugar levels. While mechanisms are not fully understood, observed hypoglycemic effects suggest potential use in diabetes management.

Liver Protection and Blood Purification:

  • Neem might have a protective impact on the liver, reducing damage caused by chemicals.
  • Stabilizes serum marker enzyme levels and increases antioxidant levels, aiding in blood purification.

Immune System Stimulation:

  • Neem is believed to stimulate both cell-mediated and lymphocytic immune systems.
  • Enhances the activity of “Killer T” cells, contributing to the body’s defense against viruses and microbes.

Brain-Protective Properties:

  • Neem’s antioxidants may offer protection against brain damage, potentially beneficial in stroke patients.
  • Raises levels of ascorbic acid (Vitamin C) and may aid in lipid peroxidation, though further research is needed.

Oral Care Applications:

  • Traditional use in rural India for teeth cleaning, owing to potential antimicrobial qualities.
  • Neem twigs, with antiseptic properties, may assist in maintaining oral hygiene and reducing gingivitis.

Stomach Health:

  • Studies suggest neem bark may reduce stomach acid secretion, regulate volume, and alleviate damage.
  • Potential anti-inflammatory properties may contribute to stomach health.

Heart Health:

  • Neem leaf extracts might help lower blood pressure, reduce clotting, and manage irregular heartbeats.
  • Further studies are essential to establish neem’s potential role in heart health.

Malaria Prevention:

  • Neem’s use as a mosquito repellent and potential effects on parasites indirectly hint at malaria prevention.

Vitiligo Treatment:

  • Neem may offer assistance in treating skin conditions like vitiligo, though additional research is required.

Skin Benefits

  • Traditional remedy for head lice and skin disorders.
  • Neem oil prevents acne and inhibits acne-causing bacteria. Active components like triterpenes, stigmasterol, nimbidin have antimicrobial properties.
  • External use of neem acts as a mosquito repellent.
  • Recognized as one of the world’s oldest skin softeners.
  • Effective in blood purification due to its detoxifying characteristics. Promotes blood circulation and aids in clearing pollutants from the bloodstream

Additional Uses

  • Integral to agroforestry, neem contributes to soil fertility, pest management, and resources for farmers.
  • Adaptable to urban environments, neem trees contribute to regreening initiatives in urban spaces.
  • Thriving in harsh conditions, neem trees are excellent sources of clean-burning fuelwood.
  • Neem wood is utilized for charcoal production, meeting domestic and industrial needs.
  • Neem ‘cake,’ a byproduct, serves as nutritious fodder for livestock, providing an additional feed source.
  • Neem ‘cake’ acts as organic mulch and fertilizer, safeguarding plants against diseases and enriching the soil.
  • Neem oil serves as a natural insect repellent, offering a chemical-free option for pest control.
  • Neem oil is utilized in skincare products due to its antiseptic properties, contributing to soap, lotion, and shampoo formulations.
  • Rapid growth and adaptability make neem trees an ideal source of clean-burning firewood.

Side Effects of Neem

  • Avoid consumption by infants due to the risk of Reye’s syndrome, which can be fatal.
  • Neem can cause allergies, skin irritation, and stomach issues in some individuals.
  • Excessive intake of neem may lead to kidney damage, particularly when consumed in large amounts.
  • Pregnant women should steer clear of neem, as it may cause miscarriages.
  • Long-term use of neem extracts may result in severe skin dryness.
  • Excessive consumption of neem may contribute to the formation of kidney stones.
  • Neem extracts can impact fertility in both men and women, affecting sperm and ovulation.
  • Toxins in neem can pass through breast milk, posing a risk to infants and affecting milk taste.
  • Excessive neem consumption may have detrimental effects on vision.

Growing and Caring Neem

Neem Tree Growing Tips

Propagation Methods: Growing a neem tree is a straightforward process, and it can be propagated either from seeds, seedlings, or saplings. If time is a constraint, purchasing a sapling from a reputable nursery is a convenient option. However, for those with the time to nurture a neem tree from a seed, it’s crucial to handle the seed with care. Keep in mind that the germination potential diminishes if the seed is stored for more than six months.

Soil and Climate Requirements: Neem trees are known for their adaptability to various soil types. While they can flourish in regions with an annual rainfall ranging from 400 to 1200 mm, they can also thrive in areas with lower rainfall. The versatility of neem trees extends to different climates, with optimal growth occurring in warmer temperatures.

Growth and Harvesting: The full maturation of a neem tree typically takes 5 to 7 years. At this stage, the tree is usually harvested for its wood. However, various parts, including leaves, flowers, and fruits, can be utilized even from a young age, adding to the tree’s practicality.

Neem Tree Care Tips

Sunlight: While neem trees are generally low-maintenance and can adapt to various conditions, they do benefit from receiving ample sunlight. Ensuring that the tree gets sufficient sunlight contributes to its overall health and growth.

Watering: Neem trees, especially when young or potted, require regular watering. However, mature neem trees do not necessitate daily watering, as they are well-suited to withstand periods of drought. Understanding the water needs at different stages of growth is essential for proper care.

Temperature Considerations: Neem trees thrive in warm temperatures, and their growth rate is highest during the summer months. It’s crucial to protect these trees from temperatures below 32 degrees Fahrenheit, as they are not well-suited for colder conditions.

Fertilizing: Once a neem tree has sprouted, it’s essential to provide regular fertilization. Using a well-balanced fertilizer, such as a 20-20-20 mixture, on a monthly basis supports the tree’s nutritional needs. Understanding the significance of each component (nitrogen, phosphorus, and potassium) ensures proper care.

Pruning Techniques: Regular pruning of neem trees is beneficial, especially when new shoots emerge. Performing pruning during the optimal times of early spring or late summer, and cutting limbs as close to the tree as possible, contributes to the overall health and strength of the tree.

Winter Care: In winter, neem trees may be susceptible to harm from low temperatures. To protect them, consider moving them indoors during this period. Additionally, reduce watering during dormancy, and provide extra cover or warmth if the tree is kept outdoors.

Pest and Diseases of Neem Plant

Pest/DiseaseDescriptionTreatment/Prevention
Damping OffPre-emergence and post-emergence damping off due to soil fungi.Cultural practices, formalin, suitable fungicides, sterilized potting media.
Leaf Web BlightCaused by Rhizoctonia solani. Greyish brown blotches on leaves.Fungicide (Bavistin), cultural practices.
Colletotrichum Leaf Spot and BlightCaused by Colletotrichum gloeosporioides. Leaf spots leading to premature defoliation.Blitox fungicide application.
Alternaria Leaf Spot and BlightCaused by Alternaria alternata. Late-season attack on leaves.Blitox fungicide at fortnightly intervals.
Pseudocercospora Leaf SpotCaused by Pseudocercospora subsessilis. Brown spots with white patches.Mancozeb in combination with Brestan.
Powdery MildewCaused by Oidium azadirachtae. White patches on leaves.Foliar spray of Bavistin fungicidal solution.
Bacterial Leaf SpotCaused by Xanthomonas azadirachtii and Pseudomonas viticola.Appropriate bactericides.
Leaf Spot and BlightCaused by Colletotrichum capsici.Fungicide application, cultural practices.
Seedling WiltCaused by Fusarium solani.Proper soil management, seed treatment.
Twig Canker and Shot HoleCaused by Phoma sp.Pruning infected twigs, fungicide application.
[Image source: https://www.fao.org/forestry/]

Environmental Impact and Sustainability of Neem Plant

  • Derived from neem trees, these fertilizers have minimal adverse effects on air, water, and soil quality. Provide an eco-friendly alternative to synthetic fertilizers.
  • Neem trees thrive in arid and semi-arid regions, making them suitable for cultivation in water-scarce areas. Contribute to sustainable agriculture practices, especially in regions with limited water resources.
  • Neem-based fertilizers are known for being less harmful to beneficial organisms, aiding in the preservation of biodiversity.
  • Neem agriculture helps in reducing the carbon footprint associated with conventional farming methods. The use of natural fertilizers minimizes the environmental impact of agricultural activities.
  • Neem acts as an environmentally “soft” natural pesticide, being specific, nontoxic to humans and other biota, and less prone to resistance. Neem materials do not kill pests outright but instead incapacitate or neutralize them through cumulative behavioral, physiological, and cytological effects. This selective approach ensures a targeted impact on pests while minimizing harm to non-target species.
  • Neem trees are planted on a large scale globally, emphasizing their recognition as a valuable resource. Adoption in various countries indicates the global acceptance of neem in addressing agricultural and environmental challenges.

Neem Products

From skincare to agriculture, and from fuel to industrial materials, neem emerges as a versatile tree with a wide range of applications, contributing to both personal well-being and sustainable practices across various industries.

Skincare and Beauty Products

  • Neem Oil: Moisturizes and soothes the skin, effective for sunburn and dry skin. It is widely used in skincare products for its therapeutic properties.

Health and Wellness Products

  • Neem Capsules: Widely used supplement believed to reduce inflammation, aid digestion, and boost the immune system.
  • Neem Juice: Popular supplement with potential health benefits such as improved digestion and reduced inflammation.

Hair Care Products

  • Neem Shampoo and Conditioner: Essential ingredients known for moisturizing, nourishing, and promoting healthy hair growth.

Environmental Sustainability

  • Neem-Based Fertilizers: Neem cake and leaves demonstrate considerable potential as fertilizers. Neem cake, a residue after oil extraction, rich in nutrients, acts as a unique and effective fertilizer. Neem leaves used for puddling in rice fields and as mulch in various crops.

Industrial Applications

  • Lubricants: Neem oil, nondrying and resistant to degradation, used as a lubricant, especially for cart wheels.
  • Timber: Neem wood, resembling mahogany, utilized in construction, furniture, and agricultural implements. Durable, resistant to termites, suitable for poles, and valued for its unique properties.
  • Fuel: Neem oil burned in lamps, and neem wood serves as a traditional source of firewood. Husk from seeds, a byproduct in pesticide manufacture, used as fuel.

Other Products

  • Resin: Exudate from trunk wounds, high in protein, used as “neem glue” and a potential food additive.
  • Bark: Contains tannins and yields strong fiber for rope weaving.
  • Honey: Neem honey commands premium prices in some Asian regions.
  • Food: Neem leaves reported to be used in chutneys, and rare “sweet” neem leaves discovered.
  • Fruit Pulp: Neem fruit pulp, a substrate for methane gas generation and a base for industrial fermentations.

Interesting Facts of Neem Plant

  • Neem’s healing history traces back to 5000 BC in Indian Ayurvedic texts, evidenced in Mohenjo-Daro around 2000 BC.
  • With over 70 terpenoids, Neem is rich in compounds, with Azadirachtin being the most active but challenging to synthesize.
  • Beyond medicine, Neem contributes to environmental care by absorbing pollutants and improving air quality.
  • Neem extracts are gaining popularity in organic agriculture due to their natural pest-repelling properties.
  • Neem’s abundant growth along South Asian and African roadsides conceals its extraordinary properties.
  • Neem cake, a byproduct, enhances soil fertility, aligning with ancient agricultural wisdom.
  • Hindu mythology attributes Neem’s healing properties to drops of heavenly nectar and links its origin to celestial beings.
  • Every part of the Neem tree is utilized in Ayurvedic medicine, with leaves addressing various ailments.
  • Neem aligns with the Hippocratic Oath, showing no reported hazards at normal dosages over millennia.
  • Neem’s adaptability and utility earned it the revered title of “The Village Pharmacy” in rural India.

Video on Use on Neem Oil For Pests

YouTube video

References

  • https://neemfoundation.org/about-neem/chemistry-of-neem/
  • https://www.cleanairgardening.com/neem-plant/
  • https://stats4sd.org/resources/neem-for-sustainable-pest-management-and-environemntal-conservation_2019-07-23_14:41:50
  • https://kaybeebio.com/blog/neem-oil-natures-pesticide-for-sustainable-agriculture/
  • https://housing.com/news/how-to-grow-and-care-for-neem-trees/
  • https://www.dabur.com/ayurveda/ayurvedic-medicinal-plants/neem

About Author

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Jyoti Bashyal

Jyoti Bashyal, a graduate of the Central Department of Chemistry, is an avid explorer of the molecular realm. Fueled by her fascination with chemical reactions and natural compounds, she navigates her field's complexities with precision and passion. Outside the lab, Jyoti is dedicated to making science accessible to all. She aspires to deepen audiences' understanding of the wonders of various scientific subjects and their impact on the world by sharing them with a wide range of readers through her writing.

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