Huperzia saururus: anticholinesterase activity and action on memory and learning

ORTEGA G, VALLEJO M, AGNESE M, CABRERA J

Recent Progress in Medicinal Plants

Studium Press

Lugar: Houston (Texas) ; Año: 2009; p. 375 - 392

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 a marked inhibition of true acetylcholinesterase with an IC50 value of 0.58 µg/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 on memory 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.