The study was to investigate the ameliorating effects of three Chinese herbs Achyranthes bidentata (AB), Ophiopogon japonicus (OJ) and Cnidium monnieri (CM) on scopolamine (SCOP)- and MK-801-induced amnesia by using a passive avoidance task in rats. AB, OJ and CM at 0.1 and 0.3 g/kg prolonged the step-through latency (STL) of the retention trial. In addition, AB, OJ and CM reversed the STL shortened by MK-801, but only AB reversed the STL shortened by SCOP. In conclusion, these Chinese herbs possess cognition-enhancing activities and anti-amnestic effects, but the mechanism of the effect of AB was different from those of OJ and CM.
