Ashwagandha (Withania somnifera), also known as Indian ginseng or Winter cherry, is one of the most important herbs in Ayurvedic medicine. It has been used for millennia as a rejuvenating tonic, i.e. to increase physical and mental health by promoting longevity. Classically, different parts of the plant (including roots, leaves and flowers) have been used to treat different conditions such as rheumatism, constipation, insomnia, chronic stress and hormonal imbalances. But the roots are the most commonly used parts of the plant: ayurvedic practitioners traditionally used to boil it in milk or mix it up with honey. Nowadays, the extract of the root is the most common form used and can be found in many herbal marketed formulations.
Ashwagandha contains various non-nutritional chemicals, responsible for medicinal properties (more than 35 phytochemicals have been identified so far). Most chemical constituents are alkaloids and steroidal lactone. Among the most well studied representatives of these substance groups are withaferin A and its structural relatives (withanolides). They are known for their anti-inflammatory and other pharmacological effects that can be used to treat brain disorders such as anxiety, depression and dementia.Most of Ashwagandha’s effects are attributed to its ability to regulate hormone secretion and to adapt the body to stress. It is, therefore, considered a strong adaptogen. Its main action is to balance cortisol, a hormone secreted by the adrenal gland in situations of prolonged stress. However, other effects have already been reported, including anti-inflammatory and antioxidant effects.
Can this ancient tonic have a role in preventing dementia?
Studies in vitro have shown that Ashwagandha is able to reduce the level of amyloid beta (Aβ) deposits in brain cells and promotes regeneration of the axon (part of the nerve cell involved in nerve impulse transmission).
In animal models, reversal of neuronal atrophy and recovery of synaptic function (transmission of stimuli from one nerve cell to another) can be observed after treatment. Prevention of memory loss and improvement of dementia symptoms have also been reported.
A few randomized clinical trials have shown improvement in executive function, attention and information processing speed in patients with mild cognitive impairment or bipolar disorder after using Ashwagandha.
The mechanism of action of Ashwagandha in the treatment of Alzheimer’s disease occurs due to stimulation of acetylcholine receptors (M1 muscarinic receptors). Acetylcholine is an important neurotransmitter, acting as a promoter of the communication between neurons (synapse). Stimulation of M1 receptors can mimic the effect of acetylcholine, improving nerve impulse transmission and reducing the symptoms of the disease, and that is exactly what Aswagandha does.
Acetlylcholine is so important in the physiopathology of Azheimer’s disease that one of the most common drugs for AD acts precisely by increasing the availability of this neurotransmitter in the brain. This group of drugs are called “cholinesterase inhibitors”, as they inhibit the enzyme ‘cholinesterase’ which is responsible for degrading acetylcholine (learn more at our section about treatment).
Future studies will clarify the real effects of Ashwagandha in Alzheimer’s disease. Meanwhile, we can count on all the knowledge of Ayurvedic medicine and use this tonic to improve memory, relieve stress and prevent Alzheimer!
Please note: the use of any herbal substance must be done under supervision of a health professional. These substances may present contraindications and side effects.
- Choudhary D, Bhattacharyya S, Bose S. Efficacy and Safety of Ashwagandha (Withania somnifera (L.) Dunal) Root Extract in Improving Memory and Cognitive Functions. J Diet Suppl. 2017 Nov 2;14(6):599-612.
- Singh N, Bhalla M, de Jager P, Gilca M. An overview on ashwagandha: a Rasayana (rejuvenator) of Ayurveda. Afr J Tradit Complement Altern Med. 2011;8(5 Suppl):208-213. doi:10.4314/ajtcam.v8i5S.9
- Konar A, Shah N, Singh R, et al. Protective role of Ashwagandha leaf extract and its component withanone on scopolamine-induced changes in the brain and brain-derived cells. PLoS One. 2011;6(11):e27265.
- Konar A, Gupta R, Shukla RK, et al. M1 muscarinic receptor is a key target of neuroprotection, neuroregeneration and memory recovery by i-Extract from Withania somnifera. Sci Rep. 2019 Sep 30;9(1):13990.
- Zahiruddin S, Basist P, Parveen A, et al. Ashwagandha in brain disorders: A review of recent developments. J Ethnopharmacol. 2020 Jul 15;257:112876.