ABSTRACT
Alternanthera philoxeroides has been used as antipyretic, dressing for wounds and ulcers in Thai traditional medicine. The present study aims to investigate the immunomodulating activity of this plant by using splenocyte proliferation test. The results showed that methanol (MeOH) extract, diethyl ether (Et₂O) and n-butanol (n-BuOH) fractions of A. philoxeroides were not cytotoxic to host cells up to the concentration tested (200 \µg/ml). For immunomodulating study, MeOH extract, Et₂O and n-BuOH fractions suppressed splenocyte proliferation. Et₂O fraction at a concentration of 50 \µg/ml significantly suppressed splenocyte proliferation (p \< 0.05). Whereas chikusetsusaponin IVa increased splenocyte proliferation in dose-dependent manner and at a concentration of 25 \µg/ml the compound significantly increased splenocyte proliferation (p \< 0.05).