Purpose: To investigate the immunomodulatory and antitumor activities of ligustilide (LIG) extracted from Angelica sinensis in mice.

Methods: Normal and tumor-bearing Institute of Cancer Research (ICR) mice were treated p.o. with LIG (5, 20 and 80 mg/kg/day) for 7 days. In normal ICR mice, phagocytosis of peritoneal macrophages and serum hemolysin concentration were assessed by chicken red blood cell ingestion test and quantitative hemolysis of sheep red blood cells assay, respectively. Lymphocyte proliferation was determined by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) method. Both cytotoxic T lymphocyte (CTL) and natural killer (NK) cell activities were evaluated by lactate-dehydrogenase-release assay. H₂₂ ascites tumor cells were inoculated subcutaneously into ICR mice, followed by the determination of antitumor activity of LIG in the H₂₂-bearing mice.

Results: LIG significantly increased thymus and spleen index, macrophage phagocytosis, serum hemolysin concentration, spleen lymphocyte proliferation and CTL and NK cell activities in normal ICR mice, but inhibited the growth of transplantable H₂₂ hepatoma. The effect was dose-related but not in a linear fashion. A dose of 20 mg/kg dose was more effective than 5 and 80 mg/kg doses.

Conclusion: These results suggest that LIG at 20 mg/kg has a highly boosted the immune system and tumor inhibition.