Effects of industrial disturbances on the flavonoid concentration ofRhododendron groenlandicum

Abstract

The boreal forest is subject to various anthropogenic disturbances, including logging, mining, and hydroelectricity production and transport. These disturbances affect Indigenous communities and the culturally salient species they depend on for the practice of traditional and subsistence activities. <i>Rhododendron groenlandicum</i> is one such species whose leaves are used to treat various ailments, due to their concentration in biologically active chemicals such as flavonoids. Our objective was to assess the effect of anthropogenic disturbances on the chemical properties of <i>R. groenlandicum</i> on the territories of three Indigenous communities. Leaf samples were collected near mines, under hydroelectric power lines, and in non-disturbed sites. Our results showed that variations in flavonoid concentration were mainly related to territory (R² = 0.43, P = 0.0005), while disturbance type had a smaller effect (R² = 0.18, P = 0.02). Samples from Nemaska, the northernmost territory with the most open forest stands, had higher concentrations of epicatechin (+23%, P = 0.03). Quercetin-3-glucoside concentrations were lower near mines (-19%, P = 0.01). The effects of disturbances on the chemical signature of <i>R. groenlandicum</i> are complex, and a complete assessment of the consequence of industrial activity on Indigenous landscape value must take into account other culturally salient species.

Phytochemical Profiling and Biological Activities of Rhododendron Subsect. Ledum: Discovering the Medicinal Potential of Labrador Tea Species in the Northern Hemisphere

“…R. tomentosum ’s flavonoids are mainly composed of flavonol glycosides, namely quercitrin, isoquercitrin, hyperoside, rutin, methylated, and phenolic acid substituted quercetin and myricetin compounds [ Figure 2 ]. The second rich fraction is flavan-3-ols with the prevailing compounds catechin, epicatechin, and B-type proanthocyanidins [ 5 , 40 , 41 , 42 ]. Dufour et al, in 2007, determined that leaves and twigs of R. groenlandicum contained 20 and 39 g/100 g of total phenolic compounds, respectively [ 35 ].…”

“…Key differences between the phenolic profiles in the latter two species were within the profile of proanthocyanidins and the presence of taxifolin derivatives [ 44 ]. Rhododendron species contain notable amounts of proanthocyanidins [ 36 , 41 , 42 , 43 , 44 ]; nevertheless, information regarding subsect. Ledum species remains scarce.…”

“…2]. The second rich fraction is flavan-3-ols with the prevailing compounds catechin, epicatechin, and B-type proanthocyanidins [5,[40][41][42]. Dufour et al, in 2007, determined that leaves and twigs of R. groenlandicum contained 20 and 39 g/100 g of total phenolic compounds, respectively [35].…”

“…The content of ursolic acid in the ethanolic extract of aerial parts of R. tomento was 15.2 mg/g [33]. L. palustre (R. tomentosum) leaves from China contained ledum uvaol, lepenone, α-amyrenone, ursolic acid, lupeol, α-amyrin, fern-9(11)-ene-2α,3βand fernenol (Figure 3) [42]. The main research on phenolic profiling was performed on species (R. tomentosum ssp.…”

“…The content of ursolic acid in the ethanolic extract of aerial parts of R. tomentosum was 15.2 mg/g [33]. L. palustre (R. tomentosum) leaves from China contained ledumone, uvaol, lepenone, α-amyrenone, ursolic acid, lupeol, α-amyrin, fern-9(11)-ene-2α,3β-diol, and fernenol (Figure 3) [42]. Study shows that the most abundant trace mineral in leaves is manganese (±706 mg/kg), with a little bit smaller amounts of aluminum, iron, zinc, copper, and nickel.…”