plants Article Bioactive Compounds in Different Buckwheat Species Gra˙ zyna Podolska 1 , El ˙ zbieta Gujska 2 , Joanna Klepacka 2 and Edyta Aleksandrowicz 1, *   Citation: Podolska, G.; Gujska, E.; Klepacka, J.; Aleksandrowicz, E. Bioactive Compounds in Different Buckwheat Species. Plants 2021, 10, 961. https://doi.org/10.3390/ plants10050961 Academic Editors: Aleksandra Golob and Mateja Germ Received: 31 March 2021 Accepted: 6 May 2021 Published: 12 May 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. 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/). 1 Department of Cereals Crop Production, Institute of Soil Science and Plant Cultivation-State Research Institute, Czartoryskich 8 Str, 24-100 Pulawy, Poland; grazyna.podolska@iung.pulawy.pl 2 Department of Commodity Science and Food Analysis, University of Warmia and Mazury in Olsztyn, Plac Cieszynski 1, 10-719 Olsztyn, Poland; elka@uwm.edu.pl (E.G.); klepak@uwm.edu.pl (J.K.) * Correspondence: edyta.aleksandrowicz@iung.pulawy.pl Abstract: The accumulation of valuable nutrients in cereal grains depends on a number of factors, including species, cultivars, and environment conditions. The aim of this study was to compare protein, some polyphenols and rutin content, as well as mineral composition in Fagopyrum tataricum and Fagopyrum esculentum genotypes growing in Polish conditions. A field experiment was con- ducted on pseudopodsolic soil in 2017–2018 at the Experimental Station in Osiny (51 ◦ 35 ′ , 21 ◦ 55 ′ ), following randomized complete block method with three replications. Two cultivars of Fagophyrum esculentum (Kora and Panda), two cultivars of Fagopyrum tataricum (LIT1 and 63181) and two forms of Fagopyrum esculentum (Red Corolla and Green Corolla) were used in this experiment. We found differences in the tested compounds (protein, phenolic acids, rutin, and mineral composition) be- tween cultivars and genotypes. Total phenolic acid and rutin contents were higher in the Fagopyrum tataricum compared to Fagopyrum esculentum. Ferulic and coumaric acids were prominent in the Kora and Panda cultivars, however vanillic and syringic acids accumulated more in Green Corolla and Red Corolla. The common buckwheat seeds contained more Cu, Mn, and Mg and less Ca than tartary buckwheat. Moreover Fagopytum esculentum genotype contains more protein compared to Fagopyrum tataricum. Keywords: Fagopyrum esculentum; Fagopyrum tataricum; cultivars; phenolic acid; rutin; minerals; protein 1. Introduction Common buckwheat (Fagopyrum esculentum) and tartary buckwheat (Fagopyrum tatar- icum) belong to the genus Fagopyrum of the family Polygonaceae, and they are among the main buckwheat species cultivated worldwide [1]. Tartary buckwheat is grown and used in the mountainous regions of southwest China, northern India, Bhutan, and Nepal. Com- mon buckwheat is grown mainly in Europe (Russian Federation, Ukraine, Poland) [2,3]. Buckwheat was brought to Poland by the Mongols in the 13th century; however, the first records of buckwheat as a cultivated plant in Poland date back to the 16th century. Records show that, since then, common and tartary buckwheat have been grown across Europe, including the countries of Russia, Ukraine, Tajikistan, Kazakhstan, Lithuania, Estonia, Belarus, Moldova, Poland, Yugoslavia, Croatia, Slovenia, Austria, France, and Italy. During the 20th century, tartary buckwheat virtually disappeared as a crop in Europe. However, Bonafaccia [4] did report that until the 1980s small quantities of tartary buckwheat were still being grown in parts of central Europe, particularly in the alpine region. Nowadays, in Poland, tartary buckwheat occurs only as a weed, contaminating the common buck- wheat fields. It seems, however, this might soon change, as in recent years interest in alternative food sources is growing and tartary buckwheat has been included in the search for novel valuable food for human consumption [5]. Impressed by its high nutritional value, researchers have been promoting the revival of this species as a “functional food.” The beneficial effects of buckwheat result from its high levels of polyphenol compounds Plants 2021, 10, 961. https://doi.org/10.3390/plants10050961 https://www.mdpi.com/journal/plants