Investigation of Phenolic Compounds and Antioxidant Activity of Sorbaria pallasii (Rosaceae) Microshoots Grown In Vitro

Sorbaria pallasii is an endemic species of the Far East and Siberia and grows along the Goltsy altitudinal belt. Data on micropropagation and phytochemical characteristics of this plant are not available, probably because of the inaccessibility of the plant material. Morphogenesis initiation from flower buds of S. pallasii in vitro and micropropagation were performed here in the Murashige and Skoog medium supplemented with 5.0 µM 6-benzylaminopurine and 0.0–1.0 µM α-naphthylacetic acid; elongation was implemented in the same medium without the hormones. A well-growing sterile culture of S. pallasii was obtained; the number of microshoots per explant reached 5.7 ± 1.2. Phytochemical analyses of in vitro propagated S. pallasii detected 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity in a water-ethanol extract from its microshoots and revealed phenolic compounds in it. The phenolic compounds that likely contribute to its biological activity are tannins (74.9 mg/g), phenolcarboxylic acids (30.8 mg/g), and catechins (13.3 mg/g). In the microshoot extract, high-performance liquid chromatography identified three catechins. Microshoots showed the highest concentration of (±)-catechin (3.03 mg/(g of absolutely dry mass; ADM)). Concentrations of epigallocatechin gallate (0.38 mg/(g of ADM)) and (−)-epicatechin (0.55 mg/(g of ADM)) were significantly lower. This study paves the way for further biotechnological and phytochemical research on S. pallasii.