Immunomodulatory Activity of a Traditional Sri Lankan Concoction of L. and G.

OBJECTIVE

To investigate the immunomodulatory activity of a traditional Sri Lankan concoction of L. and (Gaertn.) Colebr., which is a Sri Lankan traditional medicine used to relieve inflammation and cold.

METHODS

anti-inflammatory activity was tested using carrageenan-induced rat paw-edema model. Mechanism of anti-inflammatory activity was assessed by investigating the production of nitric oxide (NO), expression of iNOS enzyme, and reactive oxygen species (ROS) by rat peritoneal cells. The membrane stabilizing activity was also tested. The antibody response was determined by assessing the specific haemagglutination antibodies raised against sheep red blood cells.

RESULTS

The three doses of freeze-dried concoction used ((human equivalent dose (HED)-183 mg/kg) 2 × HED and 1/2HED;  = 6 rats/group) showed significant inhibition of paw edema compared to water control at 3-5 hours ( < 0.05). Both HED and 1/2HED exhibited marked anti-inflammatory activity (72-83% inhibition at 4-5 hours; < 0.05). The HED of the concoction showed significant inhibition of NO (77.5 ± 0.73%, < 0.001) and ROS production (26.9 ± 2.55%; < 0.01) by rat peritoneal cells. Inhibition of NO production in the concoction treated rat peritoneal cells was confirmed by the lack of iNOS expression. The concoction also exhibited significant membrane stabilizing activity (IC = 0.0006 g/ml; = 0.001). HED resulted in a significantly high induction of specific antibody production against SRBC antigens as detected by SRBC haemagglutination assay (mean day 14 titers 253.3 compared to control: 66.7) ( < 0.01).

CONCLUSIONS

The traditional Sri Lankan concoction of and demonstrated potent anti-inflammatory activity, significant reduction of ROS, and NO production by rat peritoneal cells and the lack of iNOS expression confirmed the low NO production. The increased membrane stability also supports the anti-inflammatory activity of the concoction. Further, this concoction induced a significantly high antibody response reflecting its immunostimulatory activity. Together these results scientifically validate the therapeutic use of the concoction of and in Sri Lankan traditional medicinal system for immunomodulatory effects.