In vitro biological activities of arglabin, a sesquiterpene lactone from the Chinese herb Artemisia myriantha Wall. (Asteraceae).

The immunomodulating properties of arglabin, a sesquiterpene lactone isolated from Artemisia myriantha Wall. (Asteraceae) were investigated using the murine macrophage tumor line J774.1. Arglabin-stimulated macrophages displayed a strong cytotoxic activity and the lowest doses (1.25 micrograms/mL and 0.125 micrograms/mL) induced a significant stimulation of cell mitochondrial metabolism, which correlated with [3H]TdR uptake by J774.1 cells under the same experimental conditions. In addition, the secretion of cytokines involved in host defence mechanisms--IL-1, TNF-alpha, and IL-2--was investigated upon incubation of J774-1 cells with arglabin. Arglabin triggered the production of the three cytokines from J774-1 cells. However, the pattern of cytokine secretion differed to some extent, according to the methodology used for cytokine measurement: either traditional bioassay or specific immunoassay (ELISA). Our data emphasize a possible proliferative effect of arglabin in the traditional bioassays, at least for the highest concentrations used. The results were verified with specific ELISA immunoassays. Using either method, lower concentrations of arglabin (ranging from 12.5 micrograms/mL to 0.125 micrograms/mL) were the most effective in inducing IL-1, TNF-alpha, or IL-2 secretion. In addition, preliminary data on phagocytosis showed that arglabin enhanced the uptake of fluorescent latex beads by J774.1 cells.