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

Reinier Gesto-Borroto,Karina Medina-Jiménez,Maria Luisa Villarreal,Argelia Lorence,Claudia Hornung-Leoni,Jessica P. Yactayo-Chang,Alexandre Cardoso-Taketa,Branislav T. Šiler

doi:10.1371/journal.pone.0217313

Abstract

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.

Highlights

Galphimia glauca Cav. (Malpighiaceae), is a plant that is endemic to Mexico and has been traditionally used to treat different ailments, including central nervous system disorders and inflammation [1]
Eight populations botanically classified as G. glauca were analyzed using a molecular approach by DNA barcodes and phytochemical analysis by thin-layer chromatography (TLC)
Individuals from four of these populations (GM, MC, MM and QJ) were studied previously by our group [30]. We considered these four populations because three new DNA barcodes were introduced in the molecular analysis and to compare the actual chemical profiles by TLC analysis of individuals collected in the four abovementioned localities six years previously

Summary

Introduction

Galphimia glauca Cav. (Malpighiaceae), is a plant that is endemic to Mexico and has been traditionally used to treat different ailments, including central nervous system disorders and inflammation [1]. Two metabolomic analyses were carried out in seven populations of the plant collected in the states of Chiapas, Jalisco, Morelos and Queretaro. The results of these investigations showed that only two populations produce galphimines [3,7] exhibiting anxiolytic and sedative activities in mice; all of them had anti-inflammatory activity in mice [7]. These results indicate that these plants are morphologically similar, they are different in respect to their biological activity and metabolic profile; these differences may be observed due to divergent environmental conditions or because the plants consist of different botanical species

Methods

Results

Conclusion