Phenolic Composition of sorbus (L.) genus inflorescences

Abstract

Introduction. Sorbus L. plants are very biodiverse and are widespread around the world. The raw plant materials of rowan plants, their infusions, decoctions or extracts are used in the folk medicine to treat cardiovascular [10], nervous system [1], digestive tract diseases [2] and metabolic disorders [4]. Information on the phytochemical composition variability in the raw plant materials gathered in different regions and in the raw plant materials of different species is important for increasing the variety of plants that are used for medical purposes. Materials and methods. The samples of 3 species – S. aria (L.) Crantz (Voucher specimen No. 3644), S. arranensis Hedl (Voucher specimen No. 3641), S. discolor Maxim (voucher specimen No. 3653), and 4 S. aucuparia cultivars – 'Alaja Krupnaja' (voucher specimen No. 3423), 'Nevezinskaja Zoltaja' (voucher specimen No. 3428), 'Titan' (voucher specimen No. 3424), 'Granatnaja' (voucher specimen No. 3433) were collected in the south-eastern region of Lithuania at the Botanical Garden of Vilnius University (54°43′48′′N 25°23′56′′E) and in the northern region of Lithuania at the arboretum of Rūta Stankūnienė in Linkaičiai, Joniškis district (56°12′00′′N 23°28′41′′E), in May 2012. The collected raw plant material samples were dried at room temperature and stored in a dark, dry place. For qualitative and quantitative analysis of flavonoid aglycones, extracts were prepared according to Gaivelyte et al. [3] and were hydrolyzed according to Olszewska et al. [5]. Before high performance liquid chromatography (HPLC analysis), extracts were filtered through a membrane filter with a pore size of 0.22 μm (Carl Roth GmbH, Karlsruhe, Germany). The analysis of hydrolyzed extracts was performed using isocratic HPLC method. The method was validated according to the ICH guidelines. Quantitative analysis was performed using a “Waters 2695 Alliance system” (Waters, Milford, MA, USA) with a photodiode array detector “Waters 2998”. Separation was performed using “ACE” (ACT, UK) column (C18, 150 mm × 4.6 mm, particle size 3 μm). The mobile phase of the optimized chromatographic method consisted of eluent 75 % A (0.05 % trifluoracetic acid) and 25 % B (acetonitrile). Eluent flow rate – 0.7 mL/min, injection volume – 10 μL. Column was temperature-controlled, maintained at 25°C. Contents of flavonoid aglycons were calculated at a wavelength of 370 nm. Sexangularetin and limocitrin were quantified as equivalents of isorhamnetin. The research results were re-calculated for absolutely dry raw plant material. Results and discussion. After hydrolysis of obtained extracts quercetin, kaempferol, isorhamnetin, sexagularetin and limocitin were identified. [...].