How It Works
Bottom Line: Ashwagandha slows down the growth of cancer cells in laboratory tests and enhances radiation therapy in animals. But anticancer effects have not been demonstrated in humans.
Ashwagandha is a popular Ayurvedic herb. Studies show that it has anti-inflammatory effects. Ashwagandha also relaxes the central nervous system in animals. Laboratory studies found that ashwagandha kills some cancer cells and enhances some immune cells possibly by damaging the cancer cells' ability to generate the energy it needs to reproduce. Ashwagandha also reduces the level of an important antioxidant in tumor cells, which may enhance the ability of radiation therapy to kill those cells. However, this herb may induce abortion, so pregnant women should not use it.
Purported Uses
To treat cancer
Ashwagandha has shown promise in animal and laboratory studies, but studies in humans are needed to support its use in cancer treatment.
To treat diabetes
Studies in laboratory animals suggest that ashwagandha may improve type 2 diabetes.
To treat epilepsy
No scientific evidence supports this use.
To reduce fatigue
Ashwagandha has been shown to increase blood cell counts in the lab; however, it is unclear if this will reduce fatigue in humans.
To treat digestive disorders
No scientific evidence supports this use.
To reduce pain
Ashwagandha has been shown to have a tranquilizing effect in animals, but human studies are needed.
To treat rheumatoid arthritis
A clinical trial showed that a compound of herbs and minerals containing ashwagandha reduced the pain of rheumatoid arthritis. Because the formula contained multiple herbs and minerals, whether ashwagandha played a role in the reduction in pain severity and disability is unclear.
As a sedative
Ashwagandha has been shown to have a tranquilizing effect in animals, but it is unclear if it has a similar effect in humans.
To relieve stress
In animals, ashwagandha has a tranquilizing effect; however, it is unclear if it has a similar effect in humans.
Research Evidence
Arthritis:
Forty-two volunteers with osteoarthritis participated in a trial of a herbomineral formula containing ashwagandha. Volunteers were randomly assigned to receive either a combination of herbs and minerals or placebo for three months. After a fifteen-day washout period, treatments were reversed. Volunteers in the treatment group reported significant drops in pain severity and disability score with few side effects. Because a combination of herbs was used, the extent to which ashwagandha alone can alleviate pain remains unclear.
Do Not Take If
You are pregnant. (Ashwagandha may induce abortion.)
You are taking sedatives. (Ashwagandha may increase sedative effects.)
Side Effects
Case Report: Thyrotoxicosis was reported in a 32-year-old woman following ingestion of ashwagandha capsules for chronic fatigue. Her symptoms resolved after discontinuing ashwagandha.
Scientific Name
Withania somnifera
Common Name
Ashwagandha, Indian ginseng, Winter cherry
Clinical Summary
A popular Ayurvedic herb, ashwagandha is often used in formulations prescribed for stress, strain, fatigue, pain, skin diseases, diabetes, gastrointestinal disease, rheumatoid arthritis, and epilepsy
(1). It is also used as a general tonic, to increase energy and improve health and longevity
(2). Externally, it can be applied as a local analgesic
(3). The active constituents are thought to include alkaloids, steroidal lactones, saponins, and withanolides. In vitro studies suggest that ashwagandha has anti-inflammatory properties which may protect against cartilage damage in osteoarthritis
(4). In addition, improvements in hyperglycemia, hyperinsulinemia, and insulin sensitivity have been detected in animal model of type 2 diabetes
(5).
Ashwagandha reduced growth of breast, central nervous system, colon, and lung cancer cells
(6) without inducing cell death in normal cells in vitro
(7). In addition, animal studies suggest ashwagandha has antitumor, immunomodulatory, antioxidant, and anti-stress properties. Other studies have shown cytotoxic, chemopreventative, immunomodulating
(8), and radiosensitizing effects
(1) (9) (10) in addition to enhancement in chromosomal stability
(11). The herb may also help prevent chemotherapy-induced neutropenia
(12). However, the effects of ashwagandha in cancer patients have yet to be determined.
Ashwagandha is rich in iron
(2); small scale human studies suggest ashwagandha may promote growth in children and improve hemoglobin level, red blood cell count, and sexual performance in adults
(2). An herbal tea containing ashwagandha was shown to increase natural killer cell activity in healthy volunteers with recurrent coughs and colds
(22). Data also indicate that ashwagandha may be useful in the treatment of anxiety
(23). In another clinical trial, an herbomineral formula containing ashwagandha was shown to benefit osteoarthritis
(13). Preliminary data suggest benefits of ashwagandha in improving balance in patients with progressive degenerative cereberral ataxias
(24).
Ashwagandha may induce abortion. Pregnant women should avoid this herb
(14).
Purported uses
Cancer treatment
Diabetes
Epilepsy
Fatigue
GI disorders
Health maintenance
Pain
Rheumatoid arthritis
Sedation
Skin infections
Stress
Constituents
Alkanoids: isopelletierine, anaferine
Steroidal lactones: withanolides (withaferin-A, 12-deoxywithastramonolide, and withanolide-A), withaferins
Saponins: sitoindoside VII and VIII, Iron
(2)
Mechanism of Action
Alkaloids, steroidal lactones, saponins, and withanolides are thought to be the biologically active components of ashwagandha. Studies have pointed to cyclooxygenase (COX) inhibition as the mechanism for the herb's antiarthritic properties. In animal studies, Ashwagandha's anti-inflammatory effects were comparable to hydrocortisone
(15). Microarray analysis revealed that ashwagandha represses proinflammatory gene expression, including IL-6, IL-1รข, IL-8, Hsp70, and STAT-2, and induces p38/MAPK expression in a prostate cancer cell line
(16). It exhibits antioxidant effects in the brain and tranquilizing effects on the central nervous system in animals
(2) possibly by influencing GABA receptor function
(17). Ashwagandha may inhibit tumor growth
(1) (21)and increases cytotoxic T lymphocyte production
(8). In vitro studies have shown that root extracts have cytotoxic properties against lung, colon, central nervous system, and breast cancer cell lines
(6). Withaferin A induces reactive oxygen species (ROS) generation and disruption of mitochondrial function in a human leukemia cell line, thereby inducing apoptosis
(18). In estrogen receptor-positive (ER+) and negative (ER-) breast cancer cells, withaferin A induces apoptosis and decreased tumor size
(19). Apoptosis of cancer cells by withanone is mediated through p53
(7). Other studies show ashwagandha's cytotoxicity is related to its structure; it enhances ATPase and inhibits succinate dehydrogenase activities, impairing oxidative phosphorylation. In animal studies, ashwagandha can enhance the effects of radiation therapy
(20) by reducing tumor GSH levels
(10). Ashwagandha can reverse paclitaxel-induced neutropenia in mice
(12). Significant toxicity was observed at high doses in animal studies
(20); however, toxicity studies in humans are limited
(2).
Warnings
Adverse Reactions
This herb may induce abortion. Pregnant women should avoid this herb
(14).
Case Report: Thyrotoxicosis was reported in a 32-year-old woman following ingestion of ashwagandha capsules for chronic fatigue. Her symptoms resolved after discontinuing ashwagandha
(25).
Herb-Drug Interactions
May potentiate the sedative effect of barbiturates
(14).
Literature Summary and Critique
References
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Withania somnifera root extract prevents DMBA-induced squamous cell carcinoma of skin in Swiss albino mice.
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The relationship between chondroprotective and antiinflammatory effects of Withania somnifera root and glucosamine sulphate on human osteoarthritic cartilage in vitro.
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Effect of Withania somnifera on insulin sensitivity in non-insulin-dependent diabetes mellitus rats.
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Growth inhibition of human tumor cell lines by withanolides from Withania somnifera leaves.
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Protective role of withaferin-A on 7,12-dimethylbenz(a)anthracene-induced genotoxicity in bone marrow of Syrian golden hamsters.
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Reversal of paclitaxel induced neutropenia by Withania somnifera in mice.
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13. Kulkarni RR, Patki PS, Jog VP, et al. Treatment
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-granuloma activity of Iraqi Withania somnifera.
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The dietary bioflavonoid, quercetin, selectively induces apoptosis of prostate cancer cells by down-regulating the expression of heat shock protein 90.
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17. Kulkarni SK, Akula KK, Dhir A.
Effect of Withania somnifera Dunal root extract against pentylenetetrazol seizure threshold in mice: possible involvement of GABAergic system.
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18. Malik F, Kumar A, Bhushan S, et al.
Reactive oxygen species generation and mitochondrial dysfunction in the apoptotic cell death of human myeloid leukemia HL-60 cells by a dietary compound withaferin A with concomitant protection by N-acetyl cysteine.
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19. Stan SD, Hahm ER, Warin R, et al.
Withaferin A causes FOXO3a- and Bim-dependent apoptosis and inhibits growth of human breast cancer cells in vivo.
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In vivo growth inhibitory and radiosensitizing effects of withaferin A on mouse Ehrlich ascites carcinoma.
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21. Devi PU, Sharada AC, Solomon FE.
Antitumor and radiosensitizing effects of Withania somnifera (Ashwagandha) on a transplantable mouse tumor, Sarcoma-180.
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22. Bhat J, Damle A, Vaishnav PP, et al.
In vivo enhancement of natural killer cell activity through tea fortified with Ayurvedic herbs. Phytother Res. 2010 Jan;24(1):129-35.
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Improvement of balance in progressive degenerative cerebellar ataxias after Ayurvedic therapy: a preliminary report. Neurol India. 2009 Mar-Apr;57(2):166-71.
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