Abstract
The effects of seven lignans and two neolignans derived from plants and herbs on the
concanavalin A-induced proliferation of human peripheral blood lymphocytes in vitro were studied. All compounds showed inhibitory activity with an IC50, ranging from 0.02 to 4.30 µg/ml (1.6 × 10-8 to 1.6 × 10-5M). Machilin A (2,3-dimethyl-1,4-dipiperonylbutane), a Lauraceae lignan, was the strongest
inhibitor and was quite effective as the synthetic immunosuppressive glucocorticoid
prednisolone. The viability of lymphocytes before and after treatment, as assessed
by a dye exclusion test, indicated no change, and thus the lignans are not lymphocytotoxic
but may inhibit DNA synthesis. The results suggest the value of further assessment
of plant lignans as immunosuppressive agents.
Key words
Lignans - neolignans - immunosuppressive activity - proliferation of human peripheral
blood lymphocytes - Lauraceae - machilin A - DNA synthesis
