Preliminary Report Immunomodulation by ethanolic extract of Boerhaavia diffusa roots S. Mehrotra a , K.P. Mishra a , R. Maurya b , R.C. Srimal c , V.K. Singh a, * a Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow-226 014, India b Regional Research Laboratory, Jammu-180 001, India c Industrial Toxicology Research Centre, Lucknow-226 001, India Received 14 January 2002; received in revised form 1 March 2002; accepted 10 March 2002 Abstract We have earlier reported that ethanolic extract of Boerhaavia diffusa, a plant used in Indian traditional system of medicine, significantly inhibits the cell proliferation. This led us to evaluate the immunomodulatory properties of this plant extract on various in vitro tests such as human natural killer (NK) cell cytotoxicity, production of nitric oxide (NO) in mouse macrophage cells, RAW 264.7, interleukin-2 (IL-2), tumor necrosis factor-a (TNF-a), intracytoplasmic interferon-g (IFN-g) and expression of various cell surface markers on human peripheral blood mononuclear cells (PBMCs). Ethanolic extracts of B. diffusa roots inhibited human NK cell cytotoxicity in vitro, production of NO in mouse macrophage cells, IL-2 and TNF-a in human PBMCs. Intracytoplasmic IFN-g and cell surface markers such as CD16, CD25, and HLA-DR did not get affected on treatment with B. diffusa extract. Our study demonstrates immunosuppressive potential of ethanolic extract of B. diffusa. D 2002 Elsevier Science B.V. All rights reserved. Keywords: Boerhaavia diffusa; Cell surface markers; IFN-g; IL-2; NK cells; NO; TNF-a 1. Introduction There are several medicinal plants that are consid- ered to possess immunomodulatory properties. How- ever, the available evidence is not adequate to allow their use in clinical practice. There is a need for comprehensive, systematic, multi-disciplinary evalua- tion of various claims to make effective use of these products [1]. Boerhaavia diffusa Linn (family Nycta- ginaceae) is an abundant creeping weed found all over India. In the Indian traditional system of medicine, B. diffusa roots have been widely used for the treatment of dyspepsia, jaundice, enlargement of spleen, abdominal pain, and as an anti-stress agent [2]. Liriodendrin isolated from the methanolic extract B. diffusa roots has been found to exhibit significant calcium channel antagonistic activity [3]. Treatment with aqueous extract of B. diffusa roots has been shown to induce leukocytosis with predominant neutrophilia, associated with stimulation of the phagocytic and bactericidal capacity of neutrophils and macrophages [4]. The aqueous extract of B. diffusa also protected mice against Escherichia coli-induced peritonitis [4]. Post- immunization oral administration of the alkaloid frac- 1567-5769/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII:S1567-5769(02)00031-0 * Corresponding author. Radiation Medicine Department, Armed Forces Radiobiology Research Institute, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA. Tel.: +1-301-295-9972; fax: +1-301-295-0292. E-mail address: singh@afrri.usuhs.mil (V.K. Singh). www.elsevier.com/locate/intimp International Immunopharmacology 2 (2002) 987 – 996