Immunomodulatory activity of three Sri-Lankan medicinal plants used in hepatic disorders.

The effects of aqueous extracts of Osbeckia octandra whole plant, Melothria maderaspatana whole plant and Phyllanthus debelis leaves on the human immune system were investigated. The extracts showed strong anticomplement effects on both the classical and alternate pathways of the human complement system in vitro. The effects were dose-dependent and most pronounced in the classical complement pathway assay. The extracts also exhibited a direct dose-dependent inhibition of luminol-induced chemiluminescence of human polymorphonuclear leukocytes upon stimulation with zymosan.