Phytochemical and ethnomedicinal study of Huperzia species used in the traditional medicine of Saraguros in Southern Ecuador; AChE and MAO inhibitory activity

ETHNOBOTANICAL AND ETHNOMEDICINAL RELEVANCE

This study concerns seven Huperzia species (Lycopodiaceae), namely H. brevifolia, H. columnaris, H. compacta, H. crassa, H. espinosana, H. tetragona, H. weberbaueri, which are considered sacred plants by the Saraguro community, living in the Southern Andes of Ecuador; these plants are widely used in traditional medicine and ritual ceremonies.

MATERIAL AND METHODS

The plants were selected on the basis of written interviews with 10 visionary healers (yachak) (2 women, 8 men), indicated as the most credible by the Saraguro Healers Council. The Informant Consensus Factor (F_ic) was determined. The first phytochemical study of the plants was performed by standard procedures, while the AChE and MAO-A inhibition by fractions enriched in high MW alkaloids, was measured in vitro.

AIMS OF THE STUDY

i) to investigate the uses of some Huperzia plants in healing and magical-religious practices of Saraguros; ii) to identify the main components of plant hydromethanolic extracts; iiì) to test the effects of alkaloidal fractions on the activity of two enzymes linked to mental health.

RESULTS

All the interviewed Saraguro yachak showed a high consensus about the uses of the seven Huperzia plants as purgatives and against supernatural diseases, such as the "espanto" (startle). In admixtures with other plants, some species also induce a state of trance or hallucinations in participants in magical-religious rituals. GC-MS of the volatile alkaloid fractions allowed the identification of some lycodine-type and lycopodine-type alkaloids (1-5) in H. compacta, H. columnaris, and H. tetragona. The flavones selgin) (6) and tricin (7) were isolated from H. brevifolia and H. espinosana. Tricin (7) was also detected in the other five species. The rare serratene triterpenes serratenediol (8) serratenediol-3-O-acetate (9), 21-episerratenediol (10), and 21-episerratenediol-3-O-acetate (11) were isolated from H. crassa. In addition, the presence of an unprecedented group of high molecular weight alkaloids has been determined. Alkaloid fractions of H. brevifolia, H. compacta, H. espinosana, and H. tetragona significantly inhibited AChE and MAO-A activities in vitro.

CONCLUSIONS

The first phytochemical and ethnopharmacological study of seven Huperzia plants, widely used by Saraguro healers, led to the identification of several alkaloids and triterpenoids with different remarkable biological activities. In addition, alkaloid fractions exhibited a significant AChE and MAO-A inhibitory activity. These results may support the use of these plants in brews prepared for inducing psychoactive effects in participants in magical-religious ceremonies. This study confirms the rich traditional medical knowledge of Saraguro healers which must be documented and preserved for future generations.

The Huperzia selago Shoot Tip Transcriptome Sheds New Light on the Evolution of Leaves

Lycopodiophyta—consisting of three orders, Lycopodiales, Isoetales and Selaginellales, with different types of shoot apical meristems (SAMs)—form the earliest branch among the extant vascular plants. They represent a sister group to all other vascular plants, from which they differ in that their leaves are microphylls—that is, leaves with a single, unbranched vein, emerging from the protostele without a leaf gap—not megaphylls. All leaves represent determinate organs originating on the flanks of indeterminate SAMs. Thus, leaf formation requires the suppression of indeterminacy, that is, of KNOX transcription factors. In seed plants, this is mediated by different groups of transcription factors including ARP and YABBY.

We generated a shoot tip transcriptome of Huperzia selago (Lycopodiales) to examine the genes involved in leaf formation. Our H. selago transcriptome does not contain any ARP homolog, although transcriptomes of Selaginella spp. do. Surprisingly, we discovered a YABBY homolog, although these transcription factors were assumed to have evolved only in seed plants.

The existence of a YABBY homolog in H. selago suggests that YABBY evolved already in the common ancestor of the vascular plants, and subsequently was lost in some lineages like Selaginellales, whereas ARP may have been lost in Lycopodiales. The presence of YABBY in the common ancestor of vascular plants would also support the hypothesis that this common ancestor had a simplex SAM. Furthermore, a comparison of the expression patterns of ARP in shoot tips of Selaginella kraussiana (Harrison CJ, etal. 2005. Independent recruitment of a conserved developmental mechanism during leaf evolution. Nature 434(7032):509–514.) and YABBY in shoot tips of H. selago implies that the development of microphylls, unlike megaphylls, does not seem to depend on the combined activities of ARP and YABBY. Altogether, our data show that Lycopodiophyta are a diverse group; so, in order to understand the role of Lycopodiophyta in evolution, representatives of Lycopodiales, Selaginellales, as well as of Isoetales, have to be examined.

New and existing combinations in Palaeotropical Phlegmariurus (Lycopodiaceae) and lectotypification of the type species Phlegmariurus phlegmaria (L.) T.Sen & U.Sen

The genus Phlegmariurus Holubis recognised more widely than originally proposed and is circumscribed to include both Neotropic and Palaeotropic epiphytic and terrestrial species of Huperzioid Lycopodiaceae that have isotomous shoots, lack bulbils in their sporophyllous shoots and have spores with convex lateral margins and foveolate-fossulate sculpture restricted to their distal surfaces. New combinations with Phlegmariurus are proposed for 81 species and existing combinations identified for 33 species originating from the Palaeotropics. This installs a generic circumscription that is consistent between the Neotropics and Palaeotropics. A lectotype is designated for the type species of the genus, Phlegmariurus phlegmaria (L.) T.Sen & U.Sen.

The complete chloroplast genome sequence of Huperzia javanica (sw.) C. Y. Yang in Lycopodiaceae

Huperzia javanica (Sw.) C. Y. Yang is a valuable medical herb used for treating Alzheimer’s disease. Here, we described the complete chloroplast genome of H. javanica using Illumina paired-end sequencing. The total genome length is 154,415 bp, containing 119 unique genes, with 86 protein-coding genes, 29 tRNA genes, and 4 rRNA genes. The gene content and their order are consistent with two previously reported Huperzia genomes. The overall GC content of the chloroplast genome of H. javanica is 36.4%. The topology of our maximum-likelihood tree is consistent with topologies found in previous studies, with H. javanica sister to a clade of H. serrata and H. lucidula. We support the recognition of H. javanica as an independent species. Huperzia serrata is more closely related to H. lucidula than to H. javanica.

Chloroplast-nuclear genome interaction drives asymmetric inverted repeats in chloroplast genome of Huperzia

Huperzia plants are important natural medicine species that have attracted increased amounts of attention due to the presence of huperzine A (Hup A), which efficiently, selectively, and reversibly inhibits acetylcholinesterase activity. However, due to the complexity of the genome structure and lack of genetic information, the phylogenetic and evolutionary relationships of Huperzia species are still unclear. In this study, seven chloroplast genome structures of Huperzia were verified and comparatively analyzed, and the phylogenetic relationships between Huperzia and other related ferns were evaluated. The results showed that a 58 kb insertion in the middle of the IRb region in the seven chloroplast genomes led to large differences in sequence size, GC content and tRNA number between IRa and IRb. All seven chloroplast genomes exhibited asymmetric structural conformations in the IR regions. We used sequence alignment and screening of the organelle and nuclear genomes to identify the source of the gene. The inserted sequence had no homologous region with the mitochondrial genome, and the same sequence as another segment was found in the nuclear genome. Then, the chloroplast genomes of Huperzia were comparatively analyzed. Phylogenetic tree showed that Phlegmariurus and Huperzia were closely related and belonged to the same branch. H. javanica and Huperzia serrata are closely related. From the perspective of phylogenetic tree, their phylogenetic relationship is closely related to geographical distribution. In conclusion, this study provides insights into the interaction mechanism between chloroplast genome and nuclear genome and the phylogeny of Huperzia. In addition, by comparing the chloroplast genomes of Huperzia, we analyzed its genetic diversity and provided important molecular information for the protection of these endangered species.