Safety and clinical effectiveness of Withania Somnifera (Linn.) Dunal root in human ailments

Abstract

Ethnopharmacological relevance: Withania somnifera popularly known as Aswagandha or Indian Ginseng/Poison Gooseberry have thousands years of history of use in Indian traditional medicine. Besides, finding place root of the plant as Indian Ginseng, Ayurveda also uses root of this plant as general health tonic, adaptogenic, nootropic, immunomodulatory etc. With its widespread and growing use, it becomes prudent to scientifically evaluate and document both the efficacy and safety of this plant in humans.

Aim of the study: Aswagnadha root is rapidly gaining popularity abroad for use as medicine. Current article attempts to primarily review the human efficacy and safety of Aswagandha generated through clinical trials.

Methods: A systematic search both for indexed and non-indexed literature was made for W. somnifera using various search engines and databases and the details of research articles pertaining to all clinical trials/human studies, animal studies addressing safety issues of CNS, CVS, general toxicity, mutagenicity, genotoxicity, reproductive safety and herb-drug interactions were reviewed and compiled comprehensively from full texts.

Results: A total of 69 (39 pre-clinical and 30 clinical) studies documenting efficacy and safety aspects were identified and the desired information of these studies is comprehensively presented in this review. Retrieved thirty(30) human studies demonstrated reasonable efficacy of root preparations in subclinical hypothyroidism (1), schizophrenia (3), chronic stress (2), insomnia (2), anxiety (1), memory and cognitive improvement (2), obsessive-compulsive disorder (1), rheumatoid arthritis (2), type-2 diabetes (2), male infertility (6), fertility promotion activity in females (1), adaptogenic (3), growth promoter in children (3) and chemotherapy adjuvant (1). Reasonable safety of root preparations of Aswagandha has been established by these retrieved 30 human trials. No serious adverse events or any changes in haematological, biochemical or vital parameters were reported in these human studies. Only mild and mainly transient type adverse events of somnolence, epigastric pain/discomfort and loose stools were reported as most common (>5%); and giddiness, drowsiness, hallucinogenic, vertigo, nasal congestion (rhinitis), cough, cold, decreased appetite, nausea, constipation, dry mouth, hyperactivity, nocturnal cramps, blurring of vision, hyperacidity, skin rash and weight gain were reported as less common adverse events. Pre-clinical chronic toxicity studies conducted up to 8 months also found root extracts to be safe. No mutagenicity or genotoxicity was reported for the root; only mild CNS depression and increase in thyroxine (T4) levels were reported with rootby some studies. Further, there was no in vitro and in vivo inhibition seen for CYP3A4 and CYP2D6, the two major hepatic drug metabolizing enzymes.

Conclusion: Root of the Ayurvedic drug W. somnifera (Aswagandha) appears a promising safe and effective traditional medicine for management of schizophrenia, chronic stress, insomnia, anxiety, memory/cognitive enhancement, obsessive-compulsive disorder, rheumatoid arthritis, type-2 diabetes and male infertility, and bears fertility promotion activity in females adaptogenic, growth promoter activity in children and as adjuvant for reduction of fatigue and improvement in quality of life among cancer patients undergoing chemotherapy. Properly designed, randomized-controlled, large-size, prospective trials with standardized preparations are needed to ascertain efficacy of Aswagandha root in previously studied and other new indications.

Keywords: Aswagandha; Clinical trials; General toxicity; Root; Safety.