Phytogeographic and genetic variation in Sorbus, a traditional antidiabetic medicine-adaptation in action in both a plant and a discipline.

Anna Bailie,John T Arnason,José A Guerrero-Analco,Ammar Saleem,Eliane Ubalijoro,Sebastien Renaut,Alain Cuerrier,Pierre Haddad,Timothy Johns

doi:10.7717/peerj.2645

Abstract

Mountain ash (Sorbus decora and S. americana) is used by the Cree Nation of the James Bay region of Quebec (Eeyou Istchee) as traditional medicine. Its potential as an antidiabetic medicine is thought to vary across its geographical range, yet little is known about the factors that affect its antioxidant capacity. Here, we examined metabolite gene expression in relation to antioxidant activity, linking phytochemistry and medicinal potential. Samples of leaf and bark from S. decora and S. americana were collected from 20 populations at four different latitudes. Two genes known to produce antidiabetic substances, flavonol synthase and squalene synthase, were analyzed using quantitative real time PCR. Gene expression was significantly higher for flavonol synthase compared to squalene synthase and increased in the most Northern latitude. Corresponding differences observed in the antioxidant capacity of ethanolic extracts from the bark of Sorbus spp. confirm that plants at higher latitudes increase production of stress-induced secondary metabolites and support Aboriginal perceptions of their higher medicinal potential. Modern genetic techniques such as quantitative real time PCR offer unprecedented resolution to substantiate and scrutinise Aboriginal medicinal plant perception. Furthermore, it offers valuable insights into how environmental stress can trigger an adaptive response resulting in the accumulation of secondary metabolites with human medicinal properties.

Highlights

Indigenous people have used plants as medicine for thousands of years (Arnason, Hebda & Johns, 1981)
The Canadian Institutes of Health Research (CIHR) Team on Aboriginal Antidiabetic Medicines (TAAM) studies medicinal plants used in Cree communities for symptoms of Type 2 Diabetes (T2D) (Leduc et al, 2006; Fraser et al, 2007; Cuerrier et al, 2012)
We observed that flavonol synthase gene expression was consistently higher than squalene synthase (t -test, t = 11.1, p-value = 3.14e−24, Fig. 1)

Summary

Introduction

Indigenous people have used plants as medicine for thousands of years (Arnason, Hebda & Johns, 1981). They have developed a number of non-technological approaches to identify plants and locations that will have the greatest concentration of medicinal active compounds (De Almeida, De Amorim & De Albuquerque, 2011). The Canadian Institutes of Health Research (CIHR) Team on Aboriginal Antidiabetic Medicines (TAAM) studies medicinal plants used in Cree communities for symptoms of Type 2 Diabetes (T2D) (Leduc et al, 2006; Fraser et al, 2007; Cuerrier et al, 2012). Ethnobotany, has taken advantage of new technologies and methodologies (Leduc et al, 2006; Cuerrier et al, 2015; Carrasco et al, 2016) to confirm and translate traditional concepts into scientific language

Methods

Results

Conclusion