Effect of standardized aqueous extract of Withania somniferaon tests of cognitive and psychomotor performance in healthy human participants

Abstract

Background:Withania somnifera is an herbal medicine that has been known to possess memory-enhancing properties. The current study involved an assessment of cognitive and psychomotor effects of Withania somnifera extract in healthy human participants.Materials and Methods:In this prospective, double-blind, multi-dose, placebo-controlled, crossover study, 20 healthy male participants were randomized to receive 250 mg two capsules twice daily of an encapsulated dried aqueous extract of roots and leaves of Withania somnifera or a matching placebo for a period of 14 days. Cognitive and psychomotor performance was assessed pre-dose (day 1) and at 3 hrs post-dose on day 15 using a battery of computerized psychometric tests. After a washout period of 14 days, the subjects crossed-over to receive the other treatment for a further period of 14 days as per prior randomization schedule. Same battery of test procedures were performed to assess cognitive and psychomotor performance.Results:Significant improvements were observed in reaction times with simple reaction, choice discrimination, digit symbol substitution, digit vigilance, and card sorting tests with Withania somnifera extract compared to placebo. However, no effect can be seen with the finger tapping test.Conclusion:These results suggest that Withania somnifera extract can improve cognitive and psychomotor performance and may, therefore, be a valuable adjunct in the treatment of diseases associated with cognitive impairment.

A systematic review of the clinical use of Withania somnifera (Ashwagandha) to ameliorate cognitive dysfunction

“…In terms of safety, no major adverse events were reported in any of the trials, and in a 29‐day study, no biochemical abnormalities (complete blood count, renal function, liver function tests, and lipid profile) were found at the end of study period (Pingali, Pilli, & Fatima, ).…”

A Review on Adaptogenic Activity of Ashwagandha (Withania Somnifera): An Ayurvedic Appraisal

“…The study showed significantly improved reaction time in 5 of the 6 psychomotor performance tests. Withania somnifera brings significant changes in neurological baseline functions as Sitoindosides VII-X and Withaferin A (glycowithanolides) increase cortical muscarinic acetylcholine capacity, with a modulation of cholinergic neurotransmission 44 . A double-blind, placebocontrolled comparative clinical study of effects of Withania somnifera, Panax ginseng, and placebo on psychomotor performance in 30 healthy participants concluded that there was significant improvement in sensorimotor function, auditory reaction time, and mental arithmetic ability 45 …”

Chemistry and pharmacology of withania somnifera: An update

“…In a very recent study, it is found that W. somnifera at 40 mg/kg significantly reduces the depression in various experimental models (Jayanthi et al, 2012). Clinical trials with healthy volunteers also revealed that aqueous extracts of W. somnifera improve the psychomotor performances in anxiety and depression (Pingali et al, 2014). It was assumed that W. somnifera reduces the production of nitric oxide in the brain tissues, resulting in its anxiolytic activity (Khan and Ghosh, 2011;Maity et al, 2011).…”