Likewise, animals experience a great deal of stress when under forced restraint; such animals experience fewer gastric ulcers, less behavioral despair, and less need to pump out natural "pain killers" if given Ashwagandha.

In a double-blind trial in humans, 101 healthy men aged 50 to 59 were evaluated for various aging parameters over the course of a year. Increased red blood cell levels, greater libido, and lower erythrocyte sedimentation rate (a measure of chronic inflammation) were observed in the men who got Ashwagandha instead of the dummy pills.

Ashwagandha also protects the body against immune suppression. In one study, mice were given one of three drugs that suppress the immune system, with or without Ashwagandha added to their diets. Compared with animals receiving the immunosuppressive drugs alone, animals whose diets were supplemented with Ashwagandha suffered much less suppression of bone marrow activity, with the result that they had higher hemoglobin, red blood cell count, platelet count, and body weights - and higher levels of the white blood cells of the immune system.

In another study, a mixture of sitoindosides from Ashwagandha activated the peritoneal macrophages (a kind of immune cell) in laboratory animals, increasing their mobilization and their ability to consume foreign bacteria while boosting levels of enzymes that help the body break down damaged and toxic molecules left over from the body's metabolic process. In yet a third study, administration of Ashwagandha extract to either healthy or tumor-bearing animals was found to enhance the proliferation of immune cells and their precursors in the thymus and bone marrow, actually doubling the body's response to either of two immunological challenges. Ashwagandha also boosted the activity of natural killer (NK) cells, and the immune cells' ability to destroy infected and foreign cells was enhanced.

The immune system must ride out a delicate balance, however. So the observation that Ashwagandha protects against the suppression of the immune system might lead to concerns that it might overactivate these same processes, potentially aggravating chronic inflammation and autoimmunity. So it's all the more remarkable that Ashwagandha has been found to have significant anti-inflammatory activity, reducing the autoimmune response to an animal model of arthritis to a similar degree as a cortisone drug. In another study, Ashwagandha reduced both the degeneration of the joints and the swelling induced by an arthritis-inducing drug in experimental animals.

In some kinds of chronic inflammation (especially those involving fine particles embedded in the tissue (like silica dust in the lungs) or cells infected by fungi or mycobacteria, the chronic attack of immune cells trying to clear the unclearable eventually leads to a nodule made up of densely-packed immune cells trapped within the enlarged local cells. In at least two animal studies, Ashwagandha has been shown to reduce the formation of these aggregated cellular nodules (granuloma) after injection with carageenan or implantation with cotton pellets.

Ashwagandha has traditionally been used as an Ayurvedic remedy for anxiety, an effect well documented in animal models. As well, Ashwagandha protects animals against morphine tolerance, dependence, and toxicity.

The issue of proper standardization of botanicals must always be addressed, to ensure reliable, consistent results for users. The first active compounds discovered in Ashwagandha were a family of steroidal lactones collectively called the withanolides. But more recently, a group of glucoside and saponin acyl derivatives of the withanolides - the sitoindosides - were identified. Sitoindosides are more specific markers than the withanolides, and appear to be responsible for much of the herb's anti-stress and anti-anxiety activities. Accordingly, Ashwagandha supplements should be standardized to their sitoindoside content, in addition to their withanolide levels.

References

Dhuley JN. Nootropic-like effect of Ashwagandha (Withania somnifera L.) in mice. Phytother Res 2001 Sep; 15(6): 524-8

Kuppurajan K, Rajagopalan SS, Sitaraman R, Rajgopalan V, Janaki R, Venkataraghavan S. Effect of Ashwagandha (Withania somnifera Dunal) on the process of aging in human volunteers. J Res Ayurved Siddha. 1980; 1(2):247-58

Archana R, Namasivayam A.Antistressor effect of Withania somnifera. J Ethnopharmacol 1999 Jan; 64(1): 91-3.

Bhattacharya SK, Bhattacharya A, Sairam K, Ghosal S. Anxiolytic-antidepressant activity of Withania somnifera glycowithanolides: an experimental study. Phytomedicine 2000 Dec; 7(6): 463-9.