Huperzia saururus increases memory retention in rats

Bergapten Improves Scopolamine-Induced Memory Impairment in Mice via Cholinergic and Antioxidative Mechanisms

Bergapten is a furanocoumarin naturally occurring in the Apiaceae family and it is a well-known photosensitizing agent used in photochemotherapy. In this study, we investigated the influence of bergapten on cognitive function and mechanism underlying these effects in scopolamine-induced memory impairment in male Swiss mice. The passive avoidance test was used to evaluate the efficiency of memory acquisition and consolidation. The results demonstrated that both single and repeated administration of bergapten improved not only the acquisition but also consolidation of memory. The behavioral tests showed that bergapten prevented memory impairment induced by administration of scopolamine. Observed effects may result from the inhibition of acetylcholinesterase activity in the hippocampus and prefrontal cortex. Also, bergapten caused significant anti-oxidative effects. These new findings provide pharmacological and biochemical support for the development of the coumarin’s potential in cognitive deficits.

Ethnopharmacology of the club moss subfamily Huperzioideae (Lycopodiaceae, Lycopodiophyta): A phylogenetic and chemosystematic perspective

ETHNOPHARMACOLOGICAL RELEVANCE

The most speciose subfamily Huperzioideae (Lycopodiaceae, Lycopodiophyta) contains about 276 species, and some (ca. 20 species) have traditionally been used for the treatment of e.g., dementia, rheumatism and traumatic injury. Ethnopharmacological studies have also contributed to the development of huperzine A as a drug lead, a compound first isolated from the club moss Huperzia serrata (Thunb. ex Murray) Trevis.

AIM OF THE REVIEW

This review, with a phylogenetic and chemosystematic perspective, intends to highlight plant identification challenges in these taxa with examples from club moss phytochemical and ethnopharmacological studies, as these lead to data inconsistency and confusion. We suggest that future studies should include more details on plant identification including for example plant specimen images and DNA barcoding data. An integrative approach combining DNA barcoding and chemical fingerprinting is also introduced.

MATERIALS AND METHODS

Literature concerning ethnopharmacology and chemosystematics of Huperzioideae club mosses was searched from databases, e.g. PubMed, Web of Science, SciFinder, etc. Plant names were retrieved from original publications, and compared with up-to-date taxonomic and phylogenetic status. Ethnobotanical uses and herbal preparations were summarized. Production of certain pharmaceutically interesting compounds, such as the alkaloid huperzine A, was explored in a phylogenetic context.

RESULTS

Most traditionally used club mosses are associated with psychoactivity, followed by medicinal uses against rheumatism and traumatic injury. Herbs are often prepared as infusions, decoctions or tinctures, and this implies importance of water- or aqueous-alcohol-soluble substances, such as alkaloids. Most ethnopharmacological papers on club mosses need to update or correct plant names according to recent taxonomic nomenclature, and there are still a number of unidentified species with traditional use. Advanced LC-MS chemical profiling techniques, enable distinction of genotypes of the same species as well as annotation of potential chemotaxonomic markers. In combination with DNA barcoding, chemosystematics could also help us select plant taxa with higher pharmaceutical potential. Caution should be taken when interpreting bioassay results, in terms of compounds or extract preparation and bioassay standardization.

CONCLUSION

Huperzioideae club mosses have interesting pharmaceutical potential supported by ethnopharmacological investigations. Bioprospecting of these plants should be preceded by careful plant identification to produce consistent and reproducible data. We expect that DNA barcoding and LC-MS-based chemical fingerprinting could facilitate and improve ethnopharmaceutical studies in selection of club moss taxa.

12α-hydroxy-N-demethyl-sauroxine, a lycodane type alkaloid from Phlegmariurus saururus

12α-hydroxy-N-demethyl-sauroxine (1), another new Lycopodium alkaloid from the Lycodane group, was isolated from Phlegmariurus saururus (Lam.) B. Øllg. (Lycopodiaceae). Elucidation of the chemical structure and relative stereochemistry were stated by spectroscopic data and chemical correlation. In addition, the inhibitory activity on acetylcholinesterase for 1 was determined as well as for N-methyllycodine (2), a derivative with the same nucleus, previously identified in P. saururus (IC₅₀ = 33.8 ± 0.8 μM and 547.5 ± 0.5 μM, respectively) and N-demethylsauroxine (3) whose inhibition in the actual conditions was better than the previously informed.

Lycoplanines B-D, Three Lycopodium Alkaloids from Lycopodium complanatum

A novel C₁₇N Lycopodium alkaloid (LA), lycoplanine B (1), containing an unusual formyl group, along with two new LAs, lycoplanines C (2) and D (3), were isolated from the whole plant of Lycopodium complanatum. Their structures were elucidated by extensive NMR techniques, including 1D- and 2D-NMR experiments, as well as comparing their spectral data with those of the known analogues. A possible biogenetic pathway for 1 was also proposed.

Sauroxine reduces memory retention in rats and impairs hippocampal long-term potentiation generation

In the present paper it was investigated the role of sauroxine, an alkaloid of Phlegmariurus saururus, as a modulator of some types of learning and memory, considering the potential nootropic properties previously reported for the alkaloid extract and the main alkaloid sauroine. Sauroxine was isolated by means of an alkaline extraction, purified by several chromatographic techniques, and assayed in electrophysiological experiments on rat hippocampus slices, tending towards the elicitation of the long-term potentiation (LTP) phenomena. It was also studied the effects of intrahippocampal administration of sauroxine on memory retention in vivo using a Step-down test. Being the bio distribution of a drug an important parameter to be considered, the concentration of sauroxine in rat brain was determined by GLC-MS. Sauroxine blocked LTP generation at both doses used, 3.65 and 3.610^-2μM. In the behavioral test, the animals injected with this alkaloid (3.6510^-3nmol) exhibited a significant decrease on memory retention compared with control animals. It was also showed that sauroxine reached the brain (3.435μg/g tissue), after an intraperitoneal injection, displaying its ability to cross the blood-brain barrier. Thus, sauroxine demonstrated to exert an inhibition on these mnemonic phenomena. The effect here established for 1 is defeated by other constituents according to the excellent results obtained for P. saururus alkaloid extract as well as for the isolated alkaloid sauroine.

Phytochemicals from fern species: potential for medicine applications

Ferns are an important phytogenetic bridge between lower and higher plants. Historically they have been used in many ways by humans, including as ornamental plants, domestic utensils, foods, and in handicrafts. In addition, they have found uses as medicinal herbs. Ferns produce a wide array of secondary metabolites endowed with different bioactivities that could potentially be useful in the treatment of many diseases. However, there is currently relatively little information in the literature on the phytochemicals present in ferns and their pharmacological applications, and the most recent review of the literature on the occurrence, chemotaxonomy and physiological activity of fern secondary metabolites was published over 20 years ago, by Soeder (Bot Rev 51:442-536, 1985). Here, we provide an updated review of this field, covering recent findings concerning the bioactive phytochemicals and pharmacology of fern species.

Huperzia saururus Lam. Trevis. (Lycopodiaceae) facilitates ejaculation in spinal cord transected male rats

ETHNOPHARMACOLOGICAL RELEVANCE

Huperzia saururus (Lam.) Trevis. has an extensive ethnopharmacological use, mainly because of its aphrodisiac properties. The species is consumed as decoctions or infusions in traditional medicine. The purpose of the present research was to determine if Huperzia saururus is able to increase sexual potency by evaluating the ejaculatory response, in the presence of a decoction in spinal cord transected male rats.

MATERIALS AND METHODS

The fictive ejaculation model to record the rhythmic contractions of the bulbospongiosus muscles that accompany ejaculation as an indicator of ejaculation occurrence was used. Sexually experienced male Wistar rats were used. The activation of the fictive ejaculation by the i.v. administration of a decoction was tested, as well as the effects of the oxytocinergic, cholinergic, adrenergic and nitrergic antagonism upon the pro-ejaculatory activity of Huperzia saururus.

RESULTS

Decoction (3µg/animal) was able to activate the fictive ejaculation in spinal male rats, producing a statistically significant diminution on the latency of discharge parameter and a statistically significant augment for the number of discharges. Moreover, when sequential treatments using antagonists plus decoction were administered, the effects produced showed that prazosin prevent the pro-ejaculatory effect of the decoction and that the four antagonists assayed blocked the facilitatory effect of Huperzia saururus since the facilitation in the latency of response was prevented, and the number of discharges was reduced. Together these findings support the notion that the decoction exerts an aphrodisiac effect influencing the ejaculatory potency which is partially mediated by oxytocinergic, cholinergic, adrenergic and nitrergic spinal mechanisms.

CONCLUSION

In agreement to the ethnopharmacological uses, Huperzia saururus decoction has aphrodisiac properties by influence on the ejaculatory potency.

Amino acid content and acetylcholinesterase inhibition of Huperzia saururus infusion and decoction

CONTEXT. Huperzia saururus (Lam.) Trevis. (Lycopodiaceae), an autochthonous plant species in Argentina, is used as a memory improver in traditional medicine. It was studied for this reason and the purified alkaloid extract did show significant activity on learning and memory. The species is mostly consumed in the form of infusions and decoctions.

OBJECTIVES

To evaluate the activity of the H. saururus infusion and decoction as inhibitors of acetylcholinesterase (AChE) and to determine the amino acid content in both extracts.

MATERIAL AND METHODS

Infusion and decoction were purified by ionic exchange chromatography and analyzed by high-performance liquid chromatography HPLC-UV, and the AChE inhibition of these extracts was evaluated by using the Ellman method.

RESULTS

Both infusion and decoction exerted strong AChE inhibitory activities (IC50=7.2 ± 0.4 and 22.7 ± 5.6 μg/mL, respectively). Among nine amino acids, arginine (Arg) was identified in a concentration greater than 9 mg/100 g of dried aerial parts in both extracts.

DISCUSSION AND CONCLUSION

This high content of Arg could be considered a contributing factor to the activity on memory previously demonstrated for the H. saururus alkaloid extract, since Arg is implicated indirectly in mnemonic processes as a precursor in nitric oxide synthesis. Thus, the central effect of H. saururus could involve two different mechanisms, the cholinergic mechanism and the nitric oxide pathway.

Study of the interaction of Huperzia saururus Lycopodium alkaloids with the acetylcholinesterase enzyme

In the present study, we describe and compare the binding modes of three Lycopodium alkaloids (sauroine, 6-hydroxylycopodine and sauroxine; isolated from Huperzia saururus) and huperzine A with the enzyme acetylcholinesterase. Refinement and rescoring of the docking poses (obtained with different programs) with an all atom force field helped to improve the quality of the protein-ligand complexes. Molecular dynamics simulations were performed to investigate the complexes and the alkaloid's binding modes. The combination of the latter two methodologies indicated that binding in the active site is favored for the active compounds. On the other hand, similar binding energies in both the active and the peripheral sites were obtained for sauroine, thus explaining its experimentally determined lack of activity. MM-GBSA predicted the order of binding energies in agreement with the experimental IC50 values.

Sauroine, an alkaloid from Huperzia saururus with activity in wistar rats in electrophysiological and behavioral assays related to memory retention

The present study describes the effects of sauroine (1), the main alkaloid obtained from Huperzia saururus, on memory retention and learning. To evaluate this, electrophysiological experiments and behavioral tests (step down) were performed on male Wistar rats. The results showed that 1 improved memory retention in the step-down test, significantly increasing hippocampal plasticity. Thus, 1 seems to be a constituent responsible for the activity claimed in folk medicine for H. saururus in Argentina.

Huperzine A from Huperzia species--an ethnopharmacolgical review

Huperzine A (HupA), isolated originally from a traditional Chinese medicine Qiang Ceng Ta, whole plant of Huperzia serrata (Thunb. ex Murray) Trev., a member of the Huperziaceae family, has attracted intense attention since its marked anticholinesterase activity was discovered by Chinese scientists. Several members of the Huperziaceae (Huperzia and Phlegmariurus species) have been used as medicines in China for contusions, strains, swellings, schizophrenia, myasthenia gravis and organophosphate poisoning. HupA has been marketed in China as a new drug for Alzheimer's disease (AD) treatment and its derivative ZT-1 is being developed as anti-AD new drug candidate both in China and in Europe. A review of the chemistry, bioactivities, toxicology, clinical trials and natural resources of HupA source plants is presented.