In vivo effects of Ashwagandha (Withania somnifera) extract on the activation of lymphocytes

J Altern Complement Med. 2009 Apr;15(4):423-30. doi: 10.1089/acm.2008.0215.


Objective: This study investigated the immunologic effects of Ashwagandha (Withania somnifera) on four types of immune cells in a human sample to determine the immunologic mechanism.

Design: Five (5) participants consumed 6 mL of an Ashwagandha root extract twice daily for 96 hours. Ashwagandha was administered with anupana (whole milk). Peripheral blood samples were collected at 0, 24, and 96 hours and compared for differences in cell surface expression of CD4, CD8, CD19, CD56, and CD69 receptors by flow cytometry.

Results: Significant increases were observed in the expression of CD4 on CD3+ T cells after 96 hours. CD56+ NK cells were also activated after 96 hours as evidenced by expression of the CD69 receptor. At 96 hours of use, mean values of receptor expression for all measured receptor types were increased over baseline, indicating that a major change in immune cell activation occurred across the sample.

Conclusions: Effects on immune cell activation with use of Ashwagandha warrant further study.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antigens, CD / metabolism*
  • Humans
  • Killer Cells, Natural / metabolism*
  • Lymphocyte Activation / drug effects*
  • Plant Extracts / administration & dosage
  • Plant Extracts / pharmacology*
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism*
  • Withania*


  • Antigens, CD
  • Plant Extracts