Huperzia saururus (Lam.) Trevis. (Lycopodiaceae) is used widely in
Argentinean traditional medicine as aphrodisiac and for memory
improvement. Its chemical analysis revealed the presence of the following
Lycopodium alkaloids: sauroine (novel alkaloid), sauroxine, 6-
hydroxylycopodine, N-acetyllycodine, lycopodine, lycodine, N-methyllycodine,
huperzine A and clavolonine. The alkaloid extract showed amarked inhibition
of true acetylcholinesterase with an IC50 value of 0.58 ìg/ml.
Electrophysiological experiments with purified alkaloid extract were performed on rat hippocampus slices, thus eliciting long-term potentation (LTP). Results showed a marked increase of the hippocampus synaptic plasticity. The threshold value for LTP generation was 22 ± 1.01 Hz for alkaloid extract and 86 ± 0.92 Hz for controls. Studies about the effects of the intrahippocampal administration of alkaloid extract onmemory retention in vivo (rats), using a step down test showed increased latency time, 180.00 ± 5.74 s (10 ng/rat) compared to control animals (14.89 ± 2.38 s). These same experiments were assayed with sauroine, demonstrating a significant increase of hippocampal plasticity and memory retention.
Electrophysiological experiments with purified alkaloid extract were
performed on rat hippocampus slices, thus eliciting long-term potentation
(LTP). Results showed a marked increase of the hippocampus synaptic
plasticity. The threshold value for LTP generation was 22 ± 1.01 Hz for
alkaloid extract and 86 ± 0.92 Hz for controls. Studies about the effects of
the intrahippocampal administration of alkaloid extract onmemory retention
in vivo (rats), using a step down test showed increased latency time, 180.00
± 5.74 s (10 ng/rat) compared to control animals (14.89 ± 2.38 s). These
same experiments were assayed with sauroine, demonstrating a significant
increase of hippocampal plasticity and memory retention.
