*Article* **Phenolic Compounds and Antioxidant Properties of Field-Grown and In Vitro Leaves, and Calluses in Blackberry and Blueberry**

**Tijana Kolarevi´c 1,†, Danijel D. Milinˇci´c 1,†, Tatjana Vujovi´c 2, Uroš M. Gaši´c 3, Ljiljana Proki´c 4, Aleksandar Ž. Kosti´c 1, Radosav Cerovi´c 5, Sladjana P. Stanojevic 1, Živoslav Lj. Teši´c 6 and Mirjana B. Peši´c 1,\***


† These authors equally contributed to the work.

**Abstract:** The aim of this study was to evaluate the content and profile of the phenolic compounds (PCs) and antioxidant properties of field-grown leaves, in vitro leaves and in vitro callus cultures of the blackberry 'Caˇ ˇ canska Bestrna' and blueberry 'Toro'. In vitro shoots of the selected genotypes were grown either on original Murashige and Skoog (MS) medium containing 1 mg/L BA, 0.1 mg/L IBA and 0.1 mg/L GA3 ('Caˇ ˇ canska Bestrna') or on MS medium with macroelements reduced to 1/2, 2 mg/L zeatin and 0.2 mg/L IAA ('Toro'). Callus cultures were induced from in vitro leaves and established on MS medium with 2 mg/L BA and 2 mg/L 2,4-D ('Caˇ ˇ canska Bestrna') or MS medium with half strength macroelements, 2 mg/L BA, 2 mg/L 2,4-D and 1 mg/L NAA ('Toro'). Total phenolic (TPC) and flavonoid content (TFC) were the highest in blueberry leaves, whereas low TPC and TFC values were obtained in callus cultures of both cultivars. A higher content of PCs in blueberry leaves compared to blackberry leaves was determined by the UHPLC-DAD MS/MS technique. Quercetin derivatives and phenolic acids were the dominant PCs in the leaves of both berries, whereas gallocatechin was present in a significant amount in blueberry leaves. Callus cultures of both berries had a specific PC profile, with none detected in the leaves except quercetin-3- *O*-glucoside and quercetin-3-*O*-rutinoside. Blackberry leaves showed the best antioxidant properties as estimated by ferric reducing power (FRP), ABTS•*+* and DPPH• scavenging activity assays. Callus cultures of both berries exhibited three to five times lower ABTS•*+* and ten to seventeen times lower DPPH• scavenging activity compared to corresponding leaves. The analyzed leaves and callus cultures can be a good source of PCs with good antioxidant properties and specific phenolics, respectively, for applications in the food and pharmaceutical industries.

**Keywords:** open-field plants; tissue culture plants; in vitro callus culture; *Rubus* subg. *Rubus* Watson; *Vaccinium corymbosum* L.; phenolics; radical scavenging activities; ferric reducing power

143

**Citation:** Kolarevi´c, T.; Milinˇci´c, D.D.; Vujovi´c, T.; Gaši´c, U.M.; Proki´c, L.; Kosti´c, A.Ž.; Cerovi´c, R.; Stanojevic, S.P.; Teši´c, Ž.L.; Peši´c, M.B. Phenolic Compounds and Antioxidant Properties of Field-Grown and In Vitro Leaves, and Calluses in Blackberry and Blueberry. *Horticulturae* **2021**, *7*, 420. https:// doi.org/10.3390/horticulturae7110420

Academic Editor: Alessandra Francini

Received: 31 August 2021 Accepted: 8 October 2021 Published: 20 October 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).
