Augmented primary humoral immune response and decreased cell-mediated immunity by Murraya koenigii in rats

Abstract

Murraya koenigii (Rutaceae) (curry patta: Hindi) of the family Rutaceae is used in the traditional Indian system of medicine for its immunomodulatory properties. The essential oil of the leaves of M. koenigii possesses antimicrobial, antifungal, and pesticidal activities and is used for the treatment of amebiasis, diabetes, and hepatitis. The present study was performed to evaluate the effect of M. koenigii on humoral and cell-mediated immune responses in rats. Aqueous extract of M. koenigii leaves was administered orally in a dose of 350 mg/kg. Cell-mediated immunity was assessed by measuring foot pad thickness following sensitization by injection of keyhole limpet hemocyanin and subsequent challenge by the same. Humoral immunity was assessed by measurement of hemagglutination titer to sheep red blood cells (SRBCs). In the humoral immune response, the administration of M. koenigii [350 mg/kg per os (p.o.)] from day 1 to day 7 after sensitization with SRBC on day 0 caused a significant increase in the primary anti-SRBC titer. However, the secondary immune response was decreased significantly (p<0.05) as shown by a decrease in secondary anti-SRBC titer measured on day 11 following a booster dose of antigen on day 8. In the delayed-type hypersensitivity test, M. koenigii (350 mg/kg, p.o.), when administered for 14 days, produced a significant (p<0.05) decrease in foot pad thickness when compared with the control group. Thus, these results suggest that oral administration of M. koenigii augments primary humoral immune response and decreases cell-mediated immunity.