Abstract

In our investigation, we have screened herbal drug, which consists of a mixture of seven plants, used by the tribal population (in Paderu agency area of Visakhapatnam district of Andhra Pradesh state in India), for the identification of potential immunosuppressive property by testing the aqueous extracts of the plant parts by inducing ovalbumin (OVA) specific IgG antibody responses in a murine system. The aqueous root extract of Plumbago zeylanica (PZE) exhibited the significant suppression of OVA-specific IgG antibody response determined byEnzyme-Linked Immunosorbent Assay (ELISA). PZE also suppressed the anti-OVA antibody response in dose dependent manner. In addition ethyl acetate fraction of PZE eluted from silica gel (PZE-6) was found to exert a significant suppression of OVA stimulated T cell proliferation. Moreover, PZE is potent in exerting the suppressive effect on the down regulation of anti-OVA antibody and T cell responses and in all the three haplotypes of the mice studied, which indicates that the PZE exerted immunosuppression without linking to genetic variation.

Key words: Plumbago zeylanica, immunosuppression, anti-OVA antibody response, enzyme-linked immunosorbent assay.