Animal experiment:

Mice[1]Male ICR mice weighing 28-30 g are used. For the acquisition trial, mice are initially placed in the illuminated compartment and the door between the two compartments is opened 10 s later. Each group contains ten mice. One hour or 5 h before the acquisition trial, mice receive each test agent (e.g., Timosaponin AIII 10, 20 or 40 mg/kg, p.o. ). One hour before the acquisition trial, mice receive tacrine (10 mg/kg, p.o.) as a positive control. Memory impairment is induced by scopolamine treatment (1 mg/kg, i.p.) 0.5 h or 4.5 h after the administration of test agents, tacrine, or 10% Tween 80 solution. Control animals are administered 10% Tween 80 solution alone. Twenty-four hours after the acquisition trial, the mice are again placed in the illuminated compartment for retention trials. The time taken for a mouse to enter the dark compartment after the door opened is measured as the latency time in both acquisition and retention trials, with a maximum of 300 s[1].

Timosaponin AIII could inhibit acetylcholinesterase (AChE) activity, with an IC50 of 35.4 μM.

Timosaponin AIII could inhibit acetylcholinesterase (AChE) activity, with an IC50 of 35.4 μM[1]. Timosaponin AIII is identified as a major selective cytotoxic activity in BN108, and its selective cytotoxic activity involves inhibition of mTOR, induction of ER stress and protective autophagy[2].

Of the tested steroidal saponins, Timosaponin AIII (TA3) most potently improves memory deficits. Timosaponin AIII increases the scopolamine-induced reduction in step-through latency by 17% (10 mg/kg), 28% (20 mg/kg), and 43% (40 mg/kg). During the acquisition trial, no differences in latent time are observed. Timosaponin AIII (20, 40 mg/kg, p.o.) potently inhibits this reduction of acetylcholine in scopolamine-treated mouse brain. The inhibitory effect of Timosaponin AIII is comparable to that of tacrine, which is used as a positive control[1].

References:
[1]. Lee B, et al. Timosaponin AIII, a saponin isolated from Anemarrhena asphodeloides, ameliorates learning and memory deficits in mice. Pharmacol Biochem Behav. 2009 Aug;93(2):121-7.
[2]. King FW, et al. Timosaponin AIII is preferentially cytotoxic to tumor cells through inhibition of mTOR and induction of ER stress. PLoS One. 2009 Sep 30;4(9):e7283.