DNA barcoding of the Mexican sedative and anxiolytic plant Galphimia glauca

Identification of Putative Candidate Genes from Galphimia spp. Encoding Enzymes of the Galphimines Triterpenoids Synthesis Pathway with Anxiolytic and Sedative Effects

Galphimia spp. is popularly used in Mexican traditional medicine. Some populations of Galphimia exert anxiolytic and sedative effects due to the presence of the modified triterpenoids galphimines. However, the galphimine synthesis pathway has not yet been elucidated. Hence, in this study, a comparative transcriptome analysis between two contrasting populations of Galphimia spp., a galphimine-producer, and a non-galphimine-producer, is performed using RNA-Seq in the Illumina Next Seq 550 platform to identify putative candidates genes that encode enzymes of this metabolic pathway. Transcriptome functional annotation was performed using the Blast2GO in levels of gene ontology. For differential expression analysis, edgeR, pheatmap, and Genie3 library were used. To validate transcriptome data, qPCR was conducted. In producer and non-producer plants of both populations of Galphimia spp., most of the transcripts were grouped in the Molecular Function level of gene ontology. A total of 680 differentially expressed transcripts between producer and non-producer plants were detected. In galphimine-producer plants, a larger number of highly expressed transcripts related to acyclic and polycyclic terpene synthesis were identified. As putative candidate genes involved in the galphimine synthesis pathway, P450 family members and enzymes with kinase activity were identified.

Glaucacetalin E and galphimidin B from Galphimia glauca and their anxiolytic activity

ETHNOPHARMACOLOGICAL RELEVANCE

Galphimia glauca is a Mexican medicinal plant used to treat anxiety, fear, phobia and stress as it possesses sedative properties which produce a calming effect. Although some chemical and pharmacological studies have already been carried out on G. glauca, there are still new chemical entities from this plant whose anxiolytic activity should be established.

AIM OF THE STUDY

To validate the use of G. glauca growing in Cuernavaca, Morelos, as an anti-stress agent, through the purification and structural identification of its extracts' chemical constituents; the analysis of the biogenetic relationship of its chemical compounds, and its biological evaluation to demonstrate its traditional use as anxiolytic agents.

MATERIALS AND METHODS

The structures of all isolated compounds were established based on their spectroscopic and spectrometric data. The structure of compound 2 was corroborated through X-Ray. The anxiolytic and sedative-like activities were assessed by the open-field, hole-board and exploration cylinder test.

RESULTS

The nor-triterpenes glaucacetalin E (1) and galphimidin B (2) were isolated for the first time along with seven other known compounds, one of them galphimidin (3), from the CHCl₃ fraction of the aerial parts of Galphimia glauca. The biogenesis of the natural nor-triterpenes isolated from Galphimia glauca is delineated for the first time starting from the taraxasteryl cation. Oral administration of CHCl₃ fraction and 1-3 compounds produced significant attenuation in the anxiety-response in cylinder activity, decrease in the ambulatory activity and in head dipping when compared to the vehicle. However, only the extract enhanced the pentobarbital-induced hypnosis. Diazepam was used as a positive control.

CONCLUSION

Our results suggest that G. glauca growing in Cuernavaca, Morelos, exerts anxiolytic-like activity due to the presence of the nor-triterpenes 1-3. These results reinforce the potential use of this species in the treatment of anxiety.

ITS2: An Ideal DNA Barcode for the Arid Medicinal Plant Rhazya Stricta

INTRODUCTION

In Saudi Arabia, Rhazya stricta is a widely used folkloric plant because of its various therapeutic properties. It is sold in herbal markets as a dried powder; however, the absence of visible phenotypic traits in the powder can mask its authenticity. Potential misidentification of this substance threatens consumer health. DNA barcoding could accurately identify this plant regardless of its physical state, however barcoding presents the challenge of variations in marker loci.

OBJECTIVES

The objective of this work was to assess barcode markers from the chloroplast and nuclear regions to determine their taxonomic accuracy in R. stricta barcoding, and select the best marker for this species that could fulfill the authentication test for its fresh and dried samples.

METHOD

In this study, we assessed seven barcode markers from the chloroplast (psbA-trnH, matK, rbcL, rpoB, and rpoC1) and nuclear regions (ITS1and ITS2). We compared DNA sequences of R. stricta from 50 fresh locally collected samples and 10 dried ground samples from the herbal market with the database sequences of R. stricta, R. orientalis, and eight other related species as controls. We utilized three methods (BLAST, nearest distance, and neighbor-joining tree) in this analysis.

RESULT

With the exception of psbA-trnH, all the chloroplast markers determined high similarity with other taxa. However, nuclear ITS2 best distinguished between R. stricta, R. orientalis, and other related species because of its secondary structures, which allowed for more accurate distinctions. A two-locus marker of ITS1 + ITS2 sequences also showed promising results. A two-dimensional image of our proposed marker was generated to more easily handle DNA barcoding applications.

CONCLUSION

Our study indicates that ITS2 is a cost-effective barcoding marker capable of verifying the authenticity of R. stricta and other medicinal plants in order to protect consumer health.

Further galphimines from a new population of Galphimia glauca

Both DNA barcoding and phylogenetic data of the studied botanical material suggested the existence a new population of Galphimia glauca. Their leaves afforded three new nor-3,4-seco-friedelanes named galphimines M-O, together with known galphimines D, E, G, and I. Galphimines M and N possess bicyclic orthoacetates which are the first examples of orthoesters found in the Malpighiaceae family, while galphimine O has a 27,20-δ-lactone moiety. The structures elucidation followed from spectroscopic means and the absolute configuration followed from single crystal X-ray diffraction analyses. Tests for antibacterial and antifungal activities of galphimines N and M showed no promising effects.

DNA barcoding and TLC as tools to properly identify natural populations of the Mexican medicinal species Galphimia glauca Cav

Galphimia glauca is a plant that is endemic to Mexico and has been commonly used since pre-Hispanic times to treat various illnesses, including central nervous system disorders and inflammation. The first studies investigating a natural population of G. glauca in Mexico showed that the plant has anxiolytic and sedative activities in mice and humans. The plant's bioactive compounds were isolated and identified, and they belong to a family of nor-secofriedelanes called galphimines. The integration of DNA barcoding and thin-layer chromatography analysis was performed to clarify whether the botanical classification of the populations in the study, which were collected in different regions of Mexico, as G. glauca was correct or if the populations consist of more than one species of the genus Galphimia. We employed six DNA barcodes (matK, rbcL, rpoC1, psbA-trnH, ITS1 and ITS2) that were analyzed individually and in combination and then compared each other, to indicate differences among the studied populations. In the phylogenetic analysis, ITS1 and ITS2 markers as well as the combination of all DNA regions were the most efficient for discriminating the population studied. The thin-layer chromatography analysis exhibited four principal chemical profiles, one of which corresponded to the populations that produced galphimines. DNA barcoding was consistent and enabled us to differentiate the populations that produce galphimines from those that do not. The results of this investigation suggest that the studied populations belong to at least four different species of the genus Galphimia. The phylogenetic analysis and the thin-layer chromatography chemical profiles were convenient tools for establishing a strong relationship between the genotype and phenotype of the studied populations and could be used for quality control purposes to prepare herbal medicines from plants of the genus Galphimia.

Multidisciplinary Investigations on Galphimia glauca: A Mexican Medicinal Plant with Pharmacological Potential

Galphimia glauca (Cav.) Kuntze is an important endemic plant species, which possesses many medicinal properties and has been used in the Mexican traditional medicine for its sedative, anxiolytic, anticonvulsant, antiasthmatic and antiallergic properties. The therapeutic properties of this plant are mainly due to the presence of diverse bioactive compounds such as flavonoids, triterpenoids, and phenolics. Several triterpenoids and flavonoids compounds have been isolated and identified. Modern studies have demonstrated many biological activities such as anti-inflammatory, antidiarrheal, gastroenteritis, antimalarial and cytotoxic activities. Nevertheless, many studies are restricted to the crude extract, and many bioactive compounds are yet to be identified and validated according to its traditional use. However, its commercial exploitation and use are highly limited due to the non-availability of enough plant material and lack of knowledge about its agronomical practices. Moreover, the misinterpretation and mislabeling of closely related species of the genus Galphimia Cav. as G. glauca or G. gracilis is a common problem for its rigorous scientific study and commercial exploitation. The present review provides comprehensive knowledge based on the available scientific literature. To the best of our knowledge, this is the first review on G. glauca. This comprehensive information will certainly provide a guide for the better understanding and utilization of G. glauca for its scientific and industrial exploitation.

Molecular Markers Associated With Chemical Analysis: A Powerful Tool for Quality Control Assessment of Copalchi Medicinal Plant Complex

The copalchi complex, Hintonia latiflora, H. standleyana, and Exostema caribaeum, is widely used in Mexico for treating diabetes and gastrointestinal disorders. The first therapeutic use for H. latiflora bark was registered in the "Florentine Codex" in the sixteenth century. The latest pharmacological and phytochemical studies revealed that the infusion of the leaves have hypoglycemic, antihyperglycemic and gastroprotective activities. For these reasons the monograph of the main copalchi species, H. latiflora, was recently added to the Mexican Herbal Pharmacopoeia. Nevertheless, quality control parameters are focused to the bark but not to the leaves. Moreover, information about other Rubiaceae species is needed. The main goal of this study was to generate molecular and chemical markers for quality control of the copalchi complex raw material. In addition, the resolution of the taxonomical ambiguity between H. latiflora and H. standleyana, as well as the testing of the molecular and chemical markers in different geographical batches, were aims of this study. The molecular markers and chemical profiles of the leaf infusions were generated considering three different populations for H. latiflora and separate individuals of the three species (HL, n = 10; HS, n = 3; EC, n = 4). The molecular markers matK, rbcL, trnH-psbA, rpl32-trnL, and ITS2 were tested for their discriminating capabilities. Chemical profiles of the leaf infusions were obtained by means of HPLC analyses using chlorogenic acid and 4-phenylcoumarins as chemical markers. The concatenated sequence of the molecular markers trnH-psbA, rpl32-trnL, and ITS2 clearly distinguished the three taxa, clarifying the taxonomical ambiguity of the Hintonia genus. Additionally, the chemical profiles allowed the unequivocal identification of each species supporting the molecular results; the geographical origin of the samples did not modify neither the chemical profiles nor the concatenated sequence of H. latiflora, suggesting that it is a robust identity test. The complementary use of molecular and chemical markers will assure the quality of plant material used in traditional medicine for therapeutic purposes, and should be valuable new information for the National Health authorities as a part of the Mexican Herbal Pharmacopoeia.

Sedative activity of methanolic extract of Glochidion multiloculare (Rottler ex Willd) Voigt leaves

Bangladesh is a good repository of medicinal plants. Traditional healers utilize them for treating many pathological states. Unfortunately, very few of them have been scientifically evaluated to know about the deep inside. The current study here is designed to evaluate the in vivo sedative activity of the leaves of Glochidion multiloculare (Rottler ex Willd) Voigt. With this purpose, the plant leaves were collected and powdered for extraction with methanol. Initially, the plant extract was subjected to brine shrimp lethality bioassay to monitor the presence of bioactive molecules. Later on, different neuropharmacological studies including hole cross, open field, thiopental-sodium induced sleeping time and Elevated-Plus Maze (EPM) tests were conducted to investigate sedative action. In the brine shrimp lethality bioassay, the LC50 value of the extract was found 37.19 μg mL(-1), whereas the standard vincristine sulphate showed the LC50 10.50 μg mL(-1). The moderate toxicity of the extract on brine shrimp indicated the existence of bioactive secondary metabolites in this extract. Besides, the extract decreased the locomotor activity of mice in hole cross, open field and EPM test indicating the CNS depression capability of the plant. Moreover, the extract was very much effective for prolonging the sleeping time (103 min) with quick onset of action (22 min) in comparison to the control group. The efficacy of the plant extract was found closer to the common sedative drug diazepam. Further investigations are required to explore the underlying mechanism of the sedative action and isolate bioactive principles.

A perspective on natural products research and ethnopharmacology in Mexico: the eagle and the serpent on the prickly pear cactus

Mexico's extraordinarily rich cultural and floristic diversity has fascinated explorers and researchers ever since the "New World" was discovered for and by Europeans. For many decades, natural product research has been a very active field of research in Mexico, and there also are some ongoing ethnopharmacological research efforts. This review provides an overview and critical appraisal on some key developments in these fields and examples of medicinal plants used by indigenous communities that have become of great local importance in Mexican popular medicine. In this review, the focus is on plants with effects on the CNS, diabetes, metabolic syndrome, inflammatory processes, and gastrointestinal disorders. While some of the major food plants consumed worldwide originate from southern North America, only very few medicinal plants have become of major global importance. Opuntia species are now used increasingly to manage diabetes and metabolic syndrome and represent an example of a novel medicinal product/supplement. Undoubtedly, narcotic and mind-altering drugs both have received the widest scientific interest and have attracted considerable popular attention. The history of use of the indigenous Mexican Materia Medica in the context of research on local and popular resources specifically with regard to the diverse challenges in the context of studying the world's biodiversity and the development of comparative and semiquantitative ethnobotanical research methods is discussed herein. Natural product and ethnopharmacological research in Mexico seems to have been influenced by the political and societal developments originating from the Convention on Biological Diversity (CBD) and subsequent conventions, which have not yet had the desired effect of giving value to these local resources, as they might deserve. Their equitable and sustainable implementation remains a challenge. Natural product research and ethnopharmacology will play a key role in developing an adequate evidence base for such products derived from local and traditional knowledge in Mexico.

DNA barcoding of medicinal plant material for identification

Because of the increasing demand for herbal remedies and for authentication of the source material, it is vital to provide a single database containing information about authentic plant materials and their potential adulterants. The database should provide DNA barcodes for data retrieval and similarity search. In order to obtain such barcodes, several molecular methods have been applied to develop markers that aid with the authentication and identification of medicinal plant materials. In this review, we discuss the genomic regions and molecular methods selected to provide barcodes, available databases and the potential future of barcoding using next generation sequencing.

DNA barcoding in Mexico: an introduction

DNA barcoding has become an important current scientific trend to the understanding of the world biodiversity. In the case of mega-diverse hot spots like Mexico, this technique represents an important tool for taxonomists, allowing them to concentrate in highlighted species by the barcodes instead of analyzing entire sets of specimens. This tendency resulted in the creation of a national network named Mexican Barcode of Life (MEXBOL) which main goals are to train students, and to promote the interaction and collective work among researchers interested in this topic. As a result, the number of records in the Barcode of Life Database (BOLD) for some groups, such as the Mammalia, Actinopterygii, Polychaeta, Branchiopoda, Ostracoda, Maxillopoda, Nematoda, Pinophyta, Ascomycota and Basidiomycota place Mexico among the top ten countries in the generation of these data. This special number presents only few of the many interesting findings in this region of the world, after the use of this technique and its integration with other methodologies.