Comparative Analysis of Root Phenolic Profiles and Antioxidant Activity of Five Native and Invasive Solidago L. Species

Abstract

The high environmental importance of invasive goldenrod has prompted research to find potential benefits that can be derived from these species. This study aimed to identify differences in root phenolic profiles among five Solidago species, thus providing valuable information on their potential applications and the botanical origin of the raw material. The roots of native S. virgaurea L., two alien species S. gigantea Aiton and S. canadensis L. and their hybrids S. ×niederederi Khek and S. ×snarskisii Gudž. & Žaln. were sampled from mixed-species stands in Lithuania. A complex of twelve phenolic acids and their derivatives was identified and quantified in methanol-water root extracts using the HPLC-PDA and LC/MS systems. The radical-scavenging capacities of the extracts were assessed by ABTS. The chemical content of the roots of S. virgaurea, S. gigantea and S. ×niederederi were statistically similar, while the roots of S. canadensis and S. ×snarskisii contained lower amounts of compounds than the other species. The PCA score-plot models of the phenolic profiles only partially confirmed the identification of S. ×niederederi and S. ×snarskisii as crosses between native and alien species. The findings from the phenolic profiles and the observed radical-scavenging activity of root extracts of Solidago species provide valuable insights into their potential applications in various fields.

Keywords: alien goldenrods; interspecific hybrids; phenolic acids.

Figure 1

Comparison of HPLC-PDA chromatogram profiles (λ = 330 nm) of root extracts of five Solidago spp.: (a) S. virgaurea; (b) S. canadensis; (c) S. ×niederederi; (d) S. gigantea; (e) S. ×snarskisii. Peak assignments: 1—neochlorogenic acid, 2—chlorogenic acid, 3—cryptochlorogenic acid, 4—4,5-dicaffeoylquinic acid, 5—1,5-dicaffeoylquinic acid, 6—3,5-dicaffeoylquinic acid, 7—3,4-dicaffeoylquinic acid, 8—derivative of dicaffeoylquinic acid, 9—derivative of phenolic acid I, 10—derivative of phenolic acid II, 11—derivative of phenolic acid III, 12—derivative of phenolic acid IV.

Figure 2

PCA1 model representing the concentrations of phenolic compounds in roots of S. virgaurea, S. canadensis and S. ×niederederi: (a) Loading plot of the variables contributing to PC1 and PC2; (b) Score plot of the testing root samples.

Figure 3

PCA2 model representing the concentrations of phenolic compounds in roots of S. virgaurea, S. gigantea and S. ×snarskisii: (a); Loading plot of the variables contributing to PC1 and PC2; (b) Score plot of the testing samples.

Figure 4

Radical-scavenging activity (ABTS) of the root extracts of Solidago spp.: 1—S. virgaurea; 2—S. canadensis; 3—S. ×niederederi; 4—S. gigantea; 5—S. ×snarskisii. Values followed by the different letters differ significantly between species according to the Kruskal–Wallis test (p ≤ 0.05).

Figure 5

The roots of Solidago spp.: (a) S. virgaurea; (b) S. canadensis; (c) S. ×niederederi; (d) S. gigantea (e) S. ×snarskisii. Photos by the authors.

Figure 5

The roots of Solidago spp.: (a) S. virgaurea; (b) S. canadensis; (c) S. ×niederederi; (d) S. gigantea (e) S. ×snarskisii. Photos by the authors.

Figure 6

Map of five Solidago species sampling sites in Lithuania: Numbers indicate Solidago spp. sampling sites.