Neem
StarAzadirachta indica
Synonyms: Azorella triscuspidata, Azorella trifuscata, Fischera caespitosa, Azorella trifurcata var. rahmeri, Azorella trifurcata var. normalis, Chamitis tricuspidata, Chamitis trifurcata, Azorella crassifolia, Bolax trifurcata, Bolax gilliesii, Azorella gilliesii, Bolax caespitosa, Azorella rahmeri, Azorella utriculata, Azorella albida, Chamitis complicata
Western Herbalism Properties
Traditional Uses
Beyond classical Ayurveda, neem is a ubiquitous folk medicine across the wider tropics. In West Africa the leaves and bark are used in decoctions for fevers (including as a malaria remedy), for skin infections and wounds, and as a general bitter tonic, and twigs are used as antiseptic chewing-sticks for oral hygiene (Burkill, The Useful Plants of West Tropical Africa, 1985). Throughout Southeast Asia the leaves and seed oil are applied for skin diseases and as an insect-repelling, antiparasitic remedy.
Gallery
Botanical Description
Azadirachta indica, the neem, is a fast-growing evergreen tree of the mahogany family, commonly 15 to 20 m tall, with a broad, dense, rounded crown and a short, straight trunk bearing fissured greyish-brown bark. The leaves are pinnately compound, up to about 35 cm long, with numerous curved, asymmetric, sharply toothed leaflets that are glossy green. Small, fragrant, honey-scented white flowers are borne in drooping branched panicles in the leaf axils. The fruit is a smooth, olive-like ellipsoid drupe that ripens from green to yellow, with a thin sweet pulp surrounding a hard stone containing one or two seeds rich in bitter oil. Native to the Indian subcontinent and now widely planted across the tropics, neem thrives in hot, dry, marginal soils and is renowned for its multipurpose medicinal and pesticidal uses.
Active Constituents
Azadirachtin
Limonoid (tetranortriterpenoid)Concentration: Principal bioactive limonoid, concentrated in the seed kernel.
The best-known neem limonoid; a powerful insect antifeedant/growth regulator and contributor to antiparasitic and antimicrobial activity.
Nimbin
LimonoidConcentration: Major seed/oil limonoid.
Associated with anti-inflammatory, antipyretic, antifungal and antihistaminic effects.
Nimbidin
Limonoid (sulphur-containing bitter fraction)Concentration: Major bitter principle of neem oil.
Underlies much of neem's anti-inflammatory, antiarthritic, antipyretic, antiulcer and antimicrobial activity.
Nimbolide
LimonoidConcentration: Minor limonoid of leaves/flowers.
Widely studied for antioxidant, antimalarial and anticancer (pro-apoptotic, NF-κB-modulating) activity in preclinical models.
Gedunin
LimonoidConcentration: Constituent of seed/oil.
Reported antimalarial and antifungal activity; also inhibits pancreatic α-amylase, contributing to antidiabetic potential.
Quercetin and other flavonoids
Flavonol / flavonoidsConcentration: Present in leaves and flowers.
Antioxidant and anti-inflammatory polyphenols contributing to leaf-extract activity.
β-Sitosterol and other sterols
PhytosterolsConcentration: Present across plant parts.
Contribute anti-inflammatory and lipid-modulating effects.
Azadirone / salannin and related limonoids
LimonoidsConcentration: Additional seed limonoids among 140+ characterised neem compounds.
Add to the insecticidal and antimicrobial profile of neem seed and oil.
⚠ Drug Interactions
Antidiabetic (hypoglycaemic) agents — e.g. metformin, sulfonylureas, insulin
A randomised, double-blind, placebo-controlled trial showed neem leaf/twig extract added to metformin further reduced fasting/postprandial glucose, HbA1c and insulin resistance; neem limonoids also inhibit pancreatic α-amylase. Combining with glucose-lowering drugs may have additive effects.
Clinical note: Monitor blood glucose and adjust antidiabetic dosing if neem supplements are used concurrently.
Immunosuppressants (e.g. ciclosporin, tacrolimus, corticosteroids)
Neem constituents have well-documented immunomodulatory/immunostimulant activity, which could theoretically counteract immunosuppressive therapy in transplant or autoimmune patients.
Clinical note: Avoid concentrated neem supplements in patients who must remain immunosuppressed; discuss with the treating physician.
Warfarin and CYP1A2-metabolised drugs
In vitro neem leaf extract inhibits CYP1A2, which could raise levels of CYP1A2 substrates; this has not been confirmed in humans.
Clinical note: Consider theoretical risk only with concentrated extracts; monitor if used with narrow-therapeutic-index CYP1A2 substrates.
Preparation Methods
Leaf infusion / decoction
Parts: leaves, young twigs
Dried or fresh leaves are infused/decocted and taken traditionally as a bitter tonic and for blood sugar, skin and parasitic complaints. Very bitter; use in moderation and monitor blood glucose if diabetic.
Neem oil (cold-pressed seed) — topical only
Parts: seed kernel
Used externally for skin conditions, as an insect repellent and as a scalp/hair treatment. Neem oil must NOT be ingested, especially by infants and children: internal use has caused serious toxicity (vomiting, metabolic acidosis, seizures and a Reye-like encephalopathy). It is also an abortifacient/reproductive toxin and spermicide — avoid in pregnancy and in couples seeking conception.
Neem mouthrinse / oral-care extract
Parts: leaves
Standardised leaf extract used as a mouthwash for plaque and gingivitis, per the clinical trial evidence above.
Topical leaf paste/poultice
Parts: leaves, bark
Fresh leaf paste is applied to skin infections, wounds and eruptions in traditional practice.
Clinical Studies
Evaluation of the Effect of an Aqueous Extract of Azadirachta indica (Neem) Leaves and Twigs on Glycemic Control, Endothelial Dysfunction and Systemic Inflammation in Subjects with Type 2 Diabetes Mellitus – A Randomized, Double-Blind, Placebo-Controlled Clinical Study
Over 12 weeks, aqueous neem leaf/twig extract added to metformin dose-dependently reduced fasting and postprandial glucose, HbA1c and HOMA-IR and improved endothelial function versus placebo, supporting an adjunct antidiabetic effect.
To evaluate the antigingivitis and antiplaque effect of an Azadirachta indica (neem) mouthrinse on plaque induced gingivitis: A double-blind, randomized, controlled trial
A neem mouthrinse significantly reduced plaque, gingival and bleeding indices over 21 days and was as effective as 0.2% chlorhexidine while causing fewer side effects, supporting neem as an adjunct in plaque-induced gingivitis.
Historical Texts
Ayurveda (e.g. Charaka Samhita, Sushruta Samhita) and Unani medicine
Ancient – classical (from c. 1st millennium BCE onward)Siddha medicine (Tamil tradition)
Traditional South IndianReferences
- Alzohairy MA. Therapeutics Role of Azadirachta indica (Neem) and Their Active Constituents in Diseases Prevention and Treatment . Evidence-Based Complementary and Alternative Medicine (2016) [DOI]
- Islas JF, Acosta E, G-Buentello Z, et al.. An overview of Neem (Azadirachta indica) and its potential impact on health . Journal of Functional Foods (2020) [DOI]
- Gupta SC, Prasad S, Tyagi AK, Kunnumakkara AB, Aggarwal BB. Neem (Azadirachta indica): An indian traditional panacea with modern molecular basis . Phytomedicine (2017) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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