plants Article Scopolia carniolica var. hladnikiana: Alkaloidal Analysis and Potential Taxonomical Implications Karsten Fatur * , Matjaž Ravnikar and Samo Kreft   Citation: Fatur, K.; Ravnikar, M.; Kreft, S. Scopolia carniolica var. hladnikiana: Alkaloidal Analysis and Potential Taxonomical Implications. Plants 2021, 10, 1643. https:// doi.org/10.3390/plants10081643 Academic Editor: Cecilia Cagliero Received: 7 July 2021 Accepted: 3 August 2021 Published: 10 August 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/). Department of Pharmaceutical Biology, Faculty of Pharmacy, University of Ljubljana, 32 Tržaška cesta, 1000 Ljubljana, Slovenia; Matjaz.ravnikar@ffa.uni-lj.si (M.R.); samo.kreft@ffa.uni-lj.si (S.K.) * Correspondence: karsten.fatur@gmail.com Abstract: The present research sought to compare the content of hyoscyamine/atropine and scopo- lamine in Scopolia carniolica and its contested variety, S. carniolica var. hladnikiana, with the aim of investigating differences that may be of taxonomical significance. A multi-phase liquid extraction and high-performance liquid chromatography were used to extract and analyse these alkaloids in different organs from plants collected over two years at three sites. Our results showed that hyoscyamine was almost twice as prevalent as scopolamine across our 87 samples. The differences between organ types were large, but so too were intra-organ differences; differences due to organs proved to be significant for hyoscyamine, while they were only marginally significant for scopo- lamine. The collection site also proved to have a significant influence, but only on hyoscyamine content. The year of collection and the variety proved to not be significant. Our results support the theory that these two varieties are likely one, a view argued by many others, though more work is needed to draw concrete taxonomical conclusions. Keywords: Scopolia carniolica; Scopolia carniolica var. hladnikiana; taxonomy; secondary metabolites; tropane alkaloids; Slovenia; Solanaceae 1. Introduction Named after the famed botanist, Franc Hladnik, who first discovered it, Scopolia carniolica var. hladnikiana, otherwise known as Hladnik’s Scopolia is a plant from the Solanaceae family that is endemic to a small number of discontinuous sites throughout the south eastern European country of Slovenia [1,2]. While the common S. carniolica has a distribution spanning throughout central and southeast Europe, the Hladnik variety (as of 2013) grows in only 10 confirmed sites [3]. Both varieties tend to grow in ravines within deciduous forests, especially those with high numbers of Fagus spp. [4,5]. The Hladnik variety is found growing in the presence of the normal variety. These glabrous plants are small, deciduous perennials, reaching about 20–60 cm in height and appearing in early spring [4]. Growing up from the rhizomatic rootstock, the sim- ple, ovate leaves (~10–20 × 5–8 cm) are found on short petioles alternately arranged on the stem and have simple to slightly crenate margins [4]. Campanulate flowers (15–25 mm) with floral parts of five, bloom in early spring from the leaf axils on comparably long pedicels and mature into capsules [4]. The primary distinction between S. carniolica and the Hladnik variety is that of the flower colour; while the standard variety has flowers with a deep violet colour on the outside of the corolla and a yellow colour on the inside, the Hladnik variety is a yellow- green throughout [2,4]. That being said, many other differences have been stated at various points in time, such as the Hladnik variety having shorter leaves, larger flowers, a later flowering time, and fewer flowers, while the regular variety is said to have purple leaf veins that are absent in the Hladnik variety [2,4]. However, these differences have largely proven to be inconsistent, with flower colour being the primary means of differentiating. Plants 2021, 10, 1643. https://doi.org/10.3390/plants10081643 https://www.mdpi.com/journal/plants