Phytochemical and antioxidant profiles of leaves from different Sorbus L. species.

Leaves of Sorbus L. have been used in various traditional medicine systems. Phenolic compounds determine the main pharmacological effects of Sorbus L. In this study, phytochemical and antioxidant profiles of Sorbus anglica, Sorbus aria, Sorbus arranensis, Sorbus aucuparia, Sorbus austriaca, Sorbus caucasica, Sorbus commixta, Sorbus discolor, Sorbus gracilis, Sorbus hostii, Sorbus semi-incisa and Sorbus tianschanica were determined. Twenty four constituents were identified in Sorbus L. species using ultra high performance liquid chromatography coupled to quadruple and time-of-flight mass spectrometers. Post-column FRAP assay identified compounds with reducing activity and revealed significantly greatest total antioxidant activity of 175.30 µmol TE/g DW, 169.20 µmol TE/g DW and 148.11 µmol TE/g DW in S. commixta, S. discolor and S. gracilis leaf samples, respectively, with neochlorogenic and chlorogenic acids being most significant contributors. Characteristic fingerprints of phytochemical and antioxidant profiles could be applied for the quality evaluation of various raw materials of Sorbus L. species.

Variation of quantitative composition of phenolic compounds in rowan (Sorbus aucuparia L.) leaves during the growth season.

The aim of our study was to explore variation peculiarities of qualitative and quantitative composition of phenolic compounds in leaf samples of rowan (Sorbus aucuparia L.) plants growing in natural habitats of Lithuania during their growth season using the HPLC method. In rowan leaf samples, collected during different phenological stages, qualitative and quantitative estimation of neochlorogenic acid, chlorogenic acid, caffeic acid, hyperoside, isoquercitrin, rutin, astragalin, ( - )-epicatechin, procyanidin B1 and procyanidin B2 was performed. Analysis of the qualitative and quantitative composition of phenolic compounds in ethanol extracts of leaf samples of S. aucuparia growing in natural habitats of Lithuania revealed a close relationship between the content of phenolic compounds in S. aucuparia raw plant material and different growth stages.

Phenolic and antioxidant profiles of rowan (Sorbus L.) fruits.

Fruits of different Sorbus L. species have been traditionally used in food production and in the treatment of various ailments. Besides common antioxidant active phytochemicals such as ascorbic acid, tocopherols and carotenoids, fruits are rich in phenolic compounds that are of particular interest. In this study, profiles of separate antioxidant active compounds (reducing and radical-scavenging activities) were investigated using online assays with post-column reactions. Significant variations in phenolic acids and flavonoids contents and antioxidant activity values were observed in the fruits of Sorbus L. species studied. Neochlorogenic and chlorogenic acids were determined as markers of antioxidant activity. Characteristic patterns of antioxidant profiles obtained using HPLC post-column FRAP and ABTS assays significantly depend on specific Sorbus L. species and are suitable for equivalency research of Sorbus L. fruits.

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.

Our research aim was to investigate the quantitative composition of neochlorogenic acid, chlorogenic acid, rutin, hyperoside and isoquercitrin in leaves and fruit of introduced rowan plants to Lithuania using a HPLC method. In leaf and fruit samples, quantitative estimation of neochlorogenic acid (in leaf samples 1.11-11.49 mg/g, in fruit samples 0.93-5.43 mg/g), chlorogenic acid (in leaf samples 2.74-21.91 mg/g, in fruit samples 0.55-7.50 mg/g), rutin (in leaf samples 0.03-4.88 mg/g, in fruit samples 0.02-0.39 mg/g), hyperoside (in leaf samples 0.15-7.44 mg/g, in fruit samples 0.02-1.19 mg/g) and isoquercitrin (in leaf samples 0.75-5.24 mg/g, in fruit samples 0.02-0.65 mg/g) was performed. In leaf samples, the total content of identified phenolic compounds ranged from 7.18 to 35.74 mg/g. In fruit, raw material total content of neochlorogenic acid, chlorogenic acid and identified flavonoids varied from 2.24 to 11.19 mg/g. Comparison of raw material samples of Sorbus species according to their quantitative composition of identified phenolic compounds using cluster analysis singularized S. commixta leaf and fruit samples. These contained the highest contents of chlorogenic acid, hyperoside and isoquercitrin, but also the lowest contents of neochlorogenic acid and rutin. The highest contents of neochlorogenic acid were recorded for S. lancifolia leaves, and of rutin for S. anglica leaves.