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), and topically as an analgesic (3). The active constituents include alkaloids, steroidal lactones, saponins, and withanolides.
In vitro studies suggest that ashwagandha has neuroprotective (26) (37) and 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 an animal model of type 2 diabetes (5). Other studies indicate cytotoxic, chemopreventative, immunomodulating (8), and radiosensitizing effects (1) (9) (10), and enhancement in chromosomal stability (11).
Ashwagandha is rich in iron (2). Small-scale human studies suggest that it may promote growth in children and improve hemoglobin level and red blood cell count. Ashwagandha may also improve sexual performance in adults (2) and be useful in the treatment of male infertility (27). 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 helpful for anxiety (23), to affect markers of metabolic syndrome in schizophrenia patients receiving antipsychotic therapy,(34) and to improve cognitive function in patients with bipolar disorder (35). In another clinical trial, an herbomineral formula containing ashwagandha was shown to benefit osteoarthritis (13). Preliminary data suggest that ashwagandha may help to improve balance in patients with progressive degenerative cereberral ataxias (24).
Ashwagandha reduced the growth of breast, central nervous system, colon, and lung cancer cells (6) without affecting normal cells (7), but did not show any effectiveness against drug-resistant cancer stem cells (36). Withaferin A in ashwagandha enhanced oxaliplatin effects in human pancreatic cancer cells (38). Ashwagandha was also shown to prevent chemotherapy-induced neutropenia in mice (12).
In a small study of breast cancer patients, ashwagandha alleviated chemotherapy-induced fatigue and improved quality of life. Larger trials are needed to confirm these observations (31).