Assessment of the Content of Phenolics and Antioxidant Action of Inflorescences and Leaves of Selected Species from the Genus Sorbus Sensu Stricto

Abstract

In order to find new sources of natural antioxidants, the antioxidant potential of 70% methanolic extracts from the inflorescences and leaves of 16 species from the genus Sorbus s.s. was evaluated using two complementary in vitro test systems: the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging assay and the AAPH [2,2′-azobis-(2-amidinopropane)dihydrochloride]-induced linoleic acid (LA) peroxidation test. The radical-scavenging capacities of the extracts towards the DPPH radical were in the range of 0.25−0.86 millimolar Trolox® equivalents/g dry weight. They were significantly correlated (r = -0.8089, p < 0.001) with the results of the LA-peroxidation test, indicating the Sorbus extracts to be universal antioxidants. Significant linear correlations were also found between the different antioxidant potentials and total phenolic contents as estimated by the Folin-Ciocalteu method and further verified by serial determinations of proanthocyanidins, chlorogenic acid isomers and flavonoids (|r| in the range of 0.71−0.95, p < 0.001). Cluster analysis of the data matrix identified the ten samples (inflorescences of S. aucuparia, S. pohuashanensis, S. decora, S. koehneana, S. commixta, S. gracilis, and S. sitchensis, and the leaves of S. wilfordii, S. pogonopetala, and S. gracilis) exhibiting the highest antioxidant activity and total phenolic levels and therefore the greatest potential as effective sources for natural health products.

Variation in the Contents of Neochlorogenic Acid, Chlorogenic Acid and Three Quercetin Glycosides in Leaves and Fruits of Rowan (Sorbus) Species and Varieties from Collections in Lithuania

“…The content of neochlorogenic acid determined in leaf samples during our study (converted from mg/g, 0.11-1.15 %) is close to that determined by Olszewska et al, which ranged from 0.65 to 1.15% [31], and from 0.03 to 1.10% in other species [27]. In leaf samples 0.74-2.75% [31] and 0.56-2.81% [27] of chlorogenic acid were recorded. In species and varieties that we have studied accumulation of chlorogenic acid was lower (0.27-2.19%).…”

“…Termentzi et al analyzed phenolic compounds in S. domestica fruit samples using a LC-DAD-MS (ESI+) method, determined their quantities, and found that phenolic acids are accumulated in higher amounts than flavonoids [25]. Olszewska et al studied leaves, inflorescences and fruit of Sorbus species growing in Poland and quantified the contents of flavonoids, proanthocyanidins and caffeoylquinic acid [26][27][28][29][30]. Experiments showed that total contents of flavonoids, quercetin and chlorogenic acid recorded in extracts of Sorbus plants strongly correlate with antioxidant capacity [31,32].…”

Sorbus aucuparia and Sorbus aria as a Source of Antioxidant Phenolics, Tocopherols, and Pigments

“…The data for chlorogenic and neochlorogenic acids in that study are comparable or lower than those determinated in our study. Characteristic high level of caffeoylquinic acids in Sorbus species were also reported by Gil-Izquiero and Mellenthin; [10] Hukkanen et al; [5] Olszewska et al; [17] Becerra-Herrera et al [16] Along with caffeoylquinic acids, four flavonoids have been identified and quantified by HPLC method. Quercetin and its glycosides, rutin, isoquercetin, and hyperoside were found in both species mostly in much lower quantities compared to the phenolic acids.…”

Antioxidant and antiacetylcholinesterase activities of Sorbus torminalis (L.) Crantz (wild service tree) fruits

“…It has been reported that various extracts from Sorbus species have a wide range of PC [18,20]. PC (as gallic acid equivalents) and FC (as catechin equivalents) of S. torminalis extracts are shown in Table 1.…”