Effect of naturally occurring triterpenoids glycyrrhizic acid, ursolic acid, oleanolic acid and nomilin on the immune system.

The effect of naturally occurring triterpenoid compounds such as glycyrrhizic acid, ursolic acid, oleanolic acid, and nomilin on the immune system was studied using Balb/c mice. Intraperitoneal treatments with 5 doses of these terpenoid compounds were found to enhance the total white blood cells (WBC) count. In ursolic acid, oleanolic acid and nomilin treated animals the maximum total WBC count was observed on the 6th day, while in glycyrrhizic acid treated animals it was observed only on the 9th day after the drug treatment. In ursolic acid, oleanolic acid and nomilin treated animals the percentage of increase in the total WBC count was to 91.48 +/- 4.6%, 135.75 +/- 6.4% and 117.33 +/- 17.9% respectively. In the glycyrrhizic acid treated animals the total WBC count was increased to 114.9 +/- 18%. Bone marrow cellularity and alpha-esterase positive cells were also enhanced by the treatment with these terpenoids. Treatment with various triterpenoids along with antigen produced an enhancement in the specific antibody titre and the number of plaque forming cells (PFC) in the spleen. Triterpenoids remarkably inhibited delayed type hypersensitivity reaction (DTH). These results indicate the immunomodulatory activity of naturally occurring triterpenoids such as glycyrrhizic acid, ursolic acid, oleanolic acid and nomilin.