Distribution and Botanical Identifiers
Ashwagandha (W. somnifera) grows well in arid environments and is most commonly found in the dry areas of Southeast Asia and Mediterranean regions and is also commonly cultivated outside of its natural habitat (Engels & Brinckmann, 2013a; Aslam et al., 2017). Ashwagandha is a woody shrub that grows up to 1.5 meters tall (Aslam et al., 2017). It has perfect, actinomorphic flowers with five yellow petals, five green sepals, five stamens and one pistil. The flowers possess a superior ovary, which develops into an orange spherical berry, enveloped in a green, papery calyx (Mir et al., 2013). The fruit contains multiple yellow discoid seeds (Aslam et al., 2017). The plant has simple and ovate leaves (Aslam et al., 2017). The root is a light brown fleshy taproot (Sharma et al., 2013).
Ashwagandha, a native plant of India, has a rich history of use in Indian Ayurvedic medicines with a number of alternative medicines originating from its roots (Singh et al., 2011). In Ayurveda, the plant is classified as belonging to a group of “Rasayana” herbs that promotes longevity and strength (Engels & Brinckmann, 2013a). It is also said to increase “Ojas” (Agnivesh, 2007). In the Charaka Samhita, an ancient Hindu religious text, Ojas is described as the subtlest level of physical strength and is responsible for the correlation between one’s physical body and consciousness (Agnivesh, 2007).
In addition to its rich medicinal history in India, Ashwagandha may have also been of cultural or spiritual importance in ancient Egypt. Ashwagandha berries were recovered from KV63, a chamber located in Egypt’s Valley of the Kings, near Tutankhamun’s tomb (Hamdy & Fahmy, 2018). The Ashwagandha’s berries were one of many plants woven into a floral collar, which was likely worn during a burial ceremony (Hamdy & Fahmy, 2018), suggesting its spiritual significance in Egyptian culture.
This plant has an extensive historical background, having been used medicinally for over 4000 years (Ashwagandha Advantage, 2017). Ashwagandha is believed to be mentioned in De Materia Medica, a text written in about 50 A.D. by ancient Greek physician Dioscorides, where it is referred to as Strychnos alikakabos (Berendes, 1902). In Ayurveda, it is widely regarded to be the most important of the Rasayana herbs, as the root is traditionally used for a range of purported physical and mental health conditions (Singh et al., 2011). Thus, it is taken by people of all ages to address various concerns such as to reduce stress, anxiety and blood sugar, and increase muscular strength. It is traditionally prepared by powdering the root and mixing it with butter, water or honey (Singh et al., 2011). When mixed with milk, it is used to treat malnourishment in children and when mixed with water, it can be applied topically to treat inflammation, snake bites and wounds (Singh et al., 2011). It is also an ingredient in Chyawanprash, a dietary supplement jam that contains approximately 50 medicinal plants, and is said to increase Ojas, strength, stamina, and longevity (Sharma et al., 2019).
Other common uses of Ashwagandha include strengthening immunity, stress resistance, sexual and reproductive health, and promoting youthfulness (Singh et al., 2011; Chauhan et al., 2014). In addition to the plant’s medicinal value, Ashwagandha is also used in Pakistan as fuel for cooking and heating and animal feed (Aslam et al., 2017)
Current Importance to Society
Today, the plant continues to be used as traditional medicine in many countries that it is native to and has also been adopted in many other natural medicine practices worldwide. As well, many of the aforementioned traditional uses of Ashwagandha have now been heavily researched and confirmed. The exact mechanism(s) of action responsible for many of these beneficial effects are not currently understood. However, there are a number of active constituents in Ashwagandha, namely alkaloids and steroidal lactones that might be responsible for some of its medicinal properties (Sharma et al., 2013).
When it comes to the treatment of mental health concerns, Ashwagandha serves as a valuable option. Ashwagandha is classified as an adaptogen, meaning it aids in physiologically regulating the body’s response to stressors (Singh et al., 2011). This regulatory ability is owed to withanolides; steroidal lactone compounds produced by the plant that can be converted into human hormones by the body when needed (Woolven & Snider, 2013). As such, the root has been proposed to have antidepressant properties. This is primarily attributed to its observed ability to lower serum levels of cortisol, a stress hormone (Singh et al., 2011). Additionally, withanolides have also been reported to have sedative properties, making them effective for the treatment of anxiety (Bhattacharya et al., 2000; Sharma et al., 2013). In four separate clinical trials, patients given Ashwagandha root extract reported significant improvements in their anxiety symptoms while those given placebos did not (Pratte et al., 2014). As well, a 2016 randomized controlled trial examining Ashwagandha’s efficacy at treating the anxiety disorder OCD (Obsessive Compulsive Disorder) found that subjects given Ashwagandha experienced significantly less severe symptoms than those given a placebo (Henson, 2017). This effect may be attributed to the plant’s ability to enhance the transmission of the neurotransmitter serotonin, as has been previously reported in animal studies (Henson, 2017).
In addition to depression and anxiety, Ashwagandha has been shown to be effective in treating other maladies of the brain, namely neurodegenerative disorders such as Alzheimer, Huntington and Parkinson disease. This is due to its ability to protect against oxidative stress and dendritic loss, both of which are associated with the onset of these diseases (Singh et al., 2011). Additionally, Ashwagandha root has been shown to regulate dopamine levels in the brain, making it a valuable option for the treatment of Parkinson’s disease, which is characterized by a loss of dopamine-producing cells (Rajasankar et al., 2009). It also decreases the formation of beta-amyloid plaques associated with Alzheimer’s disease (Sehgal et al., 2012). In animal studies, the root has been found to work as an acetylcholinesterase inhibitor. This means that it impedes the breakdown of acetylcholine (a neurotransmitter associated with memory), further indicating that Ashwagandha is a promising option for Alzheimer’s treatment (Hawkins, 2000).
As for Ashwagandha’s use in treating physical health concerns, it continues to be used for anti-inflammatory, strength-enhancing, aphrodisiac, and immunoprotective applications. In a randomized controlled trial conducted in 2015, young men in a resistance training program were given either Ashwagandha root extract or a placebo (Wankhede et al., 2015). Increase in muscle strength and mass were significantly larger in the group given Ashwagandha (Wankhede et al., 2015). As well, the fruits are rich in amino acids, which may also aid in building muscle strength (Sharma et al., 2013).
Some existing evidences also justify Ashwagandha’s historic use in treating inflammation. An in-vitro study conducted in 2012 found that hydroalcoholic extracts from dried Ashwagandha root powder inhibited denaturation of the protein albumin (Chandra et al., 2012). Since tissue protein denaturation is a major underlying cause of inflammation, Ashwagandha is a promising option for the treatment of inflammatory conditions such as arthritis (Chandra et al., 2012). These anti-inflammatory properties have been widely attributed to withanolides, which may work synergistically with several alkaloids to produce this effect (Chandra et al., 2012). In addition to Ashwagandha on its own, Ariflex tablets (which contain Ashwagandha root extract as well as extracts of several other medicinal plants) also serve as an option for the treatment of osteoarthritis. In a 2020 study assessing the efficacy of the drug in treating osteoarthritis of the knee, mean WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain, stiffness, and function scores decreased by 79%, 82% and 74% respectively after taking ariflex for 180 days. Additionally, none of the subjects experienced swelling after 150 days (Nipanikar et al., 2020).
There is also scientific validity behind Ashwagandha’s long-held status as an aphrodisiac. Withanolides derived from the leaves and roots of Ashwagandha work to combat decreases in testosterone associated with aging (Lopresti et al., 2019). The root also increases nitric oxide production, which enhances blood circulation, allowing Ashwagandha to work as a natural Viagra, combatting erectile dysfunction (Iuvone et al., 2003). A study conducted in 2013 reported a significant (167%) increase in sperm count associated with the consumption of Ashwagandha root extract (Ambiye et al., 2013). Lastly, following treatment with Ashwagandha, studies analyzing the metabolic profiles of blood and semen obtained from infertile men found significant increases in a number of metabolites, hormones and enzymes which indicates improvement in fertility (Gupta et al., 2013).
Ashwagandha root extract also continues to be used for its immunoprotective effects, owed to its ability to increase white blood cell counts (Mikolai et al., 2009). A rat study showed that the root extract up regulates T helper type 1 cells in immunosuppressed rats, aiding in defense against viruses (Khan et al., 2006). Two studies conducted in 2009 further investigated these properties and found that participants given a tea containing Ashwagandha (in addition to holy basil, licorice, cardamom and ginger) experienced a significant increase in NK (natural killer) cells, a type of white blood cell that plays a role in immune response by killing infected cells (Engels & Brinckmann, 2013b). Ashwagandha roots and leaves exhibit antimicrobial activity against a vast array of fungi and bacteria (Girish et al., 2006).
Ashwagandha is also a promising choice for the treatment of a variety of physical health concerns that are immensely common in modern society such as cancer, diabetes, and hypothyroidism. Ashwagandha leaves have been reported to possess anti-cancer properties (Sharma et al., 2013). One such mechanism behind this is the ability of withanolides to activate cell death in cancerous cells (Ichikawa et al., 2006). Additionally, it was found that the leaf extract of Ashwagandha inhibits tumour formation in mice and reduces tumour size via the upregulation of the tumour suppressor protein p53 (Wadhwa et al., 2013). It is also valuable in conjunction with other cancer treatments. It allows lower doses of radiation than typically used to be equally effective at destroying cancer cells, thus minimizing the negative side effects of radiation. Additionally, when coupled with the cancer drug cyclophosphamide, it protects against myelosuppression (decreased activity of bone marrow), which is a common adverse side effect of the drug (Hawkins, 2001). Lastly, a 2013 clinical trial found that Ashwagandha significantly decreased fatigue associated with chemotherapy in breast cancer patients (Engels & Brinckmann, 2013).
The root and leaf extracts of Ashwagandha are a valuable option for the treatment of diabetes, as they are able to decrease blood glucose levels more effectively than the hypoglycemic drug glibenclamide (Udayakumar et al., 2009). This can likely be attributed to compounds called flavonoids found in the plant, however, the specific compounds responsible still need to be characterized (Udayakumar et al., 2009).
Lastly, in a double-blind randomized controlled clinical trial examining patients with hypothyroidism, treatment with Ashwagandha root extract regulated serum levels of thyroid hormones suggesting that it can be a potential alternative to taking synthetic thyroid hormones (Sharma et al., 2017).
Ashwagandha is becoming an increasingly economically important plant, with sales between 2016 and 2017 increasing by 9,413 % (Ashwagandha Advantage, 2017). In Canada, there are currently 325 licensed natural health products on the market in which Ashwagandha is an active ingredient (Engels & Brinckmann, 2013a). In India, Ashwagandha is the fourth most consumed medicinal plant in terms of volume (Engels & Brinckmann, 2013). With increased research regarding the scientific basis behind its various modes of action giving rise to its medicinal properties, Ashwagandha will likely continue to be immensely economically important in the future.
The global conservation status of Ashwagandha is currently unknown, as it has not yet been assessed by the IUCN Red List (Aslam et al., 2017). However, its decline as observed in the Himalayan and Salt regions of Pakistan has led to its classification as endangered specie within Pakistan. In Pakistan, Ashwagandha specifically falls under IUCN criteria A, meaning that a population size reduction has been observed, is currently being observed, or is projected to occur in the future (Aslam et al., 2017; IUCN, 2019). The population size reduction can be attributed to numerous factors. One of the major issue is habitat loss that is resulting from anthropogenic activities, primarily deforestation (Aslam et al., 2017). Additionally, over-exploitation of this plant due to medicinal properties is a concern in Pakistan, where the majority of Ashwagandha is collected from the wild (Aslam et al., 2017). Lastly, increasing temperatures and drought associated with climate change are placing immense stress on Ashwagandha (Aslam et al., 2017).
About the Author
Andrea J Moreau is a University of Guelph graduate with a BSc in biology and a minor in plant science. She is currently pursuing a graduate certificate in Environmental Visual Communication from Fleming College. She is passionate about knowledge mobilization, particularly through writing. Her ultimate dream is to use her love of science communication to address current world issues and inspire coming generations of scientists.