Effects of biodynamic preparations on concentration of phenolic compounds in the leaves of two white mulberry cultivars

ABSTRACT The aim of this study was to evaluate the influence of biodynamic (BD) preparations 500 and 501 on the quality of white mulberry (Morus alba L.) leaves. Leaves of the two mulberry cultivars, Plodovaja 3 and Turchanka, were collected in September 2015 and 2016. Quantitative determinations of phenolic, flavonoid and chlorogenic acid concentrations in mulberry leaves were conducted by UPLC methods. The results showed that the total phenolic compounds concentration (TPCC) and total flavonoid concentration (TFC) in the samples ranged from 4483 to 5005 and from 2944 to 3292 mg ChAE 100 g−1 DM, respectively, with leaves of Turchanka containing the highest concentrations and significant differences between the cultivars for treatments with BD application. The major flavonoids in the mulberry leaves were quercetin-acetylhexoside, isoquercitrin, rutin, kaempferol-acetylhexoside and astragalin, and the concentration of these varied depending on the cultivar (apart from for isoquercitrin and astragalin). The results demonstrated that BD preparations influenced the TPCCs of the two cultivars differently. The application of BD preparation 500 significantly increased the total phenolic and flavonoid concentrations in the leaves of Turchanka by 3.62% and 6.1%, respectively. Using the two preparations together (500 + 501) had significant effects on quercetin-acetylhexoside and kaempferol-acetylhexoside accumulation in the mulberry leaves of both cultivars. Application of preparation 501 significantly reduced the TPCC, TFC and chlorogenic acid concentration in the leaves of Plodovaja 3, compared with the control. The results showed that BD preparations had the greatest positive effect on the accumulation of phenolic compounds in the leaves of the Turchanka cultivar.