Ashwagandha is, arguably, one of the most important tonics of Ayurvedic herbal medicine. There is a lot to say regarding the therapeutic benefits of ashwagandha, but others will cover that more than adequately. What I’d like to address in this blog is:
- there is not really a single ashwagandha
- specific quality-control (QC) issues
- thoughts regarding the use of the leaves versus roots.
Ashwagandha is the Sanskrit common name typically applied to the botanical Withania somnifera. While there is only a single Withania somnifera, there are, in actuality, at least six different chemotypes of this particular species in trade. "Chemotype" means the same plant growing in different habitats will develop distinctly different chemical patterns. This may be due to environmental factors or genetic influences of that particular species growing in a respective bioregion. While each of these chemotypes yields varying amounts of the important active compounds known as withanolides, they may occur in different ratios and with different co-constituents. This is sometimes a nightmare for regulatory folks who want everything to look the same all the time, and so sometimes gives rise to regulators claiming noncompliance with regulatory requirements. However, diversity in botanical species is a unique hallmark of plants; regulators need to broaden their understanding of what constitutes good quality material. Referencing the traditional data usually provides such guidance.
From a QC perspective, the manner in which the material is grown—ideally without the use of pesticides—the time of harvest, the manner in which the plant parts are dried, the organoleptic characteristics (taste, smell, feel), and presence and amount of withanolides are the primary markers of quality. The Ayurvedic Pharmacopoeia is the primary reference that sets standards for Ayurvedic herbs. It established a minimum quality limit of 0.15 percent withanolides for the crude material and that it have a bitter and acrid flavor.
Finally, in recent years, the industry has seen some controversy between the use of the leaves along with the roots in some preparations. By far, it is the roots that have been used historically much more than the leaves. Generally speaking, leaves were often used topically and seldom used internally. Up until several years ago, ashwagandha products exclusively used the roots, and leaves were considered to possess toxic compounds. At the same time, the leaves are a rich source of withanolides, which are among the desired markers for regulatory compliance and are used by some to increase withanolide yields. This led to the introduction of a new extract prepared from root and leaf. While the preponderance of traditional data is clear that it is the root that is used, there are a number of scientific papers supporting the safety and efficacy of the leaf and root combination product, the potentially toxic components purportedly being removed from the leaf portion. At the same time, the National Institute Of Ayurveda in Jaipur and the Indian Ministry Of Health do not allow for the addition of the leaf to root products, as it is only the root that is specified for use in the Ayurvedic and Indian Pharmacopoeias.