Neem Oil Health Benefits and Side effects

neem oil health benefits

Introduction

Neem oil is obtained from the seed kernels of the neem tree (Azadirachta indica) of family Meliaceae. This oil has a huge medicinal value and thus widely used in Chinese, Ayurvedic, and Unani medicines. Other common names of neem oil are Margosa oil or Indian Lilac oil. Neem oil main health benefits are related to its use in traditional medicine in India for various diseases like headache, gastrointestinal disorders, male contraceptive, menstrual disorder, asthma.

Constituents of Neem oil

contain at least 100 biologically active compounds. Among them, the major constituents are triterpenes known as limonoids, including azadirachtin, meliantriol, nimbin, nimbidin, nimbinin, nimbolides, fatty acids (oleic, stearic, and palmitic), and salannin.

15 Neem oil Health benefits

1. Neem oil is rich in antioxidants

Terpenes and phenolics are found in neem oil having antioxidant activity and scavenge the free radicals thus play an important role in disease prevention (1).

2. Anti-inflammatory properties of neem oil

The phenolic compounds containing catechin and triterpenoid nimibidin found in neem oil reduce inflammation, pain, and swelling. Studies show that neem oil (2 ml/kg) is beneficial for the reduction in paw edema (52.99%) within 3 hrs (2).

3. Inhibits prostate and breast cancer growth

Anticancer properties Neem seed oil is beneficial for the inhibition of breast and prostate cancer. This oil due to limonoids compounds inhibits the growth of cancer cells by reduction of tumor incidence (80%) (3, 4).

4. Healthy skin

Because of essential fatty acids and vitamin E, neem oil penetrates deep within the skin to heal the minute cracks brought on by severe dryness (5). 

Neem oil is showing wonderful effect on skin diseases such as scrofula, indolent ulcers, and ringworm.  This oil also helps to treat chronic skin conditions like Acne, psoriasis, eczema and stubborn warts (6).

5. Healthy teeth

Various natural bioactive compounds in neem oil have an antimicrobial effect to reduce plaque formation and keep oral health. Thus neem oil may be helpful against plaque formation with lesser side effects (7).

6. Neem oil as Mosquito repellents

Neem oil shows larvicidal activity against important vectors of malaria, filaria, Japanese encephalitis, dengue and dengue hemorrhagic fever, epidemic polyarthritis, yellow fever, and chikungunya.  

This oil proved five times more toxic than the other oil for reductions on growth (80%) for Anopheles, Culex and Aedes larvae (8).

7. Insecticidal property of Neem oil 

It contains good amount of azadirachtin, nimbin, and other compounds which show insecticide effect against pests like Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera, Neuroptera,  mango hopper and Podisus nigrispinus (9). 

This oil cause death of insects and inhibits growth and survival and results in anomalies on the wings and legs of the pest. It also reduces fecundity and fertility, changes behavior and cause anomalies in eggs, larvae, and adults of insects or mites (10).

8. Neem oil treats radiation dermatitis

Neem oil is beneficial for the treatment of acute skin toxicity for patients undergoing radiotherapy or chemo-radiotherapy for head and neck cancer because of its anti-inflammatory properties (11).

9. Wound healing properties of Neem oil

In Ayurveda, Neem (Azadirechta indica A. Juss) oil combined with Haridra (Curcuma longa Linn.) powder capsule are used and effective for chronic non-healing wounds. Nimbidin present in neem oil is highly bitter and contains sulfur which has antifungal, antibacterial and keratolytic properties. Therefore,  neem oil and Haridra powder are very useful to treat diabetic chronic wounds and show wonderful effect on leprotic, venous, and decubitus ulcer (12).

10. Antifungal properties of Neem oil

Triterpenoidal and tetranortriterpenoid compounds obtained from neem oil inhibit mycotoxin production and show fungitoxic effect by inhibition of growth and sporulation of Penicillium verrucosum and P. brevicompactum (13).

11. Antibacterial properties of Neem oil

The active compound in neem oil inhibits the growth of various bacteria such as Staphylococcus aureus, Salmonella typhosa, Streptococcus mutans, Streptococcus faecalis, Carnobacterium maltaromaticum, Brochothrix thermosphacta, Escherichia coli, Pseudomonas fluorescens, Lactobacillus curvatus and L. sakei (14).

12. Neem oil can be used as a Pet care

A skin disorder is common in dogs known as atopic dermatitis and is a concern for humans coming in contact. However, neem oil is effective, improves the clinical signs of skin disorders and show wonderful effect on the improvement of atopic dermatitis in dogs (15).

13. Feeding broilers with neem oil produces low cholesterol chicken meat

Neem oil is significantly effective to reduce low-density lipoprotein (bad cholesterol) with diets supplemented 20 g of neem oil/kg. Therefore, feeding broilers with neem seed oil has a beneficial effect on the production of low‐cholesterol chicken meat as demand by health‐conscious consumers. (16)

14. Prevent mycotoxin production

Zearalenone, a mycotoxin produced by fungi of the genus Fusarium, including F. graminearum, triggers reproduction disorders in certain animals and hyperestrogen syndromes in humans. However, Neem oil extract decreased zearalenone amount which is toxic to animals and human beings (17).

15. Neem Oil can be used for birth control

A research study suggested that neem oil acts as a powerful spermicide. It lowers the sperm density and motility due to arrest of spermatogenesis. 

Neem oil also applied intravaginally before sexual intercourse prevents pregnancy. Rhesus monkey and human spermatozoa, for example, became totally immotile within 30 seconds of contacting the neem oil. Therefore, Neem oil possesses antifertility properties and use as an ideal contraceptive because it is a natural product, readily available, inexpensive, and non-toxic (18).

Side effects of Neem oil

1. Risk of encephalopathy

Azadirachtin (tetranortriterpenoid) found in neem oil sometimes cause poisoning with symptoms like vomiting, seizures, metabolic acidosis, and toxic encephalopathy. Therefore, if you feel these symptoms you should avoid neem oil application (19).

2. Risk of toxic optic neuropathy

Consumption of neem oil (150 ml) causes bilateral loss of vision of a person with resulted cytotoxic edema due to tissue hypoxia. Therefore a high amount of neem oil may be toxic, so consult your doctor before consumption (20).

3. Risk of Reye’s syndrome

Neem oil ingestion cause vomiting, drowsiness, metabolic acidosis, polymorphonuclear leucocytosis, and encephalopathy which occurs within minutes to hours which resulted in the loss of consciousness and coma (21).

4. Risk of metabolic acidosis and seizures

Accidentally consumption of neem oil by child cause severe metabolic acidosis along with seizures which can be refractory with known late neurological sequelae. Thus precaution should be needed (22).

5. Risk of liver injury

Neem seed oil is non-toxic when given via oral route but when given intravenously or intraperitoneally, it caused death. Moreover, high consumption of neem oil 4 times per week developed hepatotoxicity by an increase in the weights of liver and lung which is an indication of the toxic effects of this oil.

Therefore, the use of neem or its products may also be a reason for damage to liver and kidney that may result in jaundice and in low or no urine production  (23).

6. Unpleasant odor

Neem oil gives unpleasant pungent odor which enhanced on increasing the dose. Therefore theses repulsive garlicky odor of neem oil is one of the drawbacks of application of this oil. (24)

Edited By: Dr. Asha Jyoti Bharati

References

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4791507/
  2. http://www.jhrr.org/article.asp?issn=2394-2010;year=2014;volume=1;issue=3;spage=66;epage=69;aulast=Naik
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734358/
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3584965/
  5. https://pdfs.semanticscholar.org/7d12/b2e18e0d1dd020c16658b38b093c6cc3a7c5.pdf
  6. https://www.ncbi.nlm.nih.gov/pubmed/18280906
  7. https://www.ncbi.nlm.nih.gov/pubmed/23066297/
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1887534/
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5011654/
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4130301/
  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4300176/
  12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4492024/
  13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3202777/
  14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5302226/
  15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3800901/
  16. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6682791/
  17. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3769831/
  18. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3331377/
  19. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3841499/
  20. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4061674/
  21. https://www.ncbi.nlm.nih.gov/pubmed/6110100/
  22. https://www.ncbi.nlm.nih.gov/pubmed/18250509/
  23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6475536/
  24. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6542315/

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