plants Article UHPLC Analysis of Reynoutria japonica Houtt. Rhizome Preparations Regarding Stilbene and Anthranoid Composition and Their Antimycobacterial Activity Evaluation Fabian Alperth, Lena Melinz, Johannes-Paul Fladerer and Franz Bucar * Institute of Pharmaceutical Sciences, University of Graz, Beethovenstraße 8, 8010 Graz, Austria;
[email protected] (F.A.);
[email protected] (L.M.); johannes.fl
[email protected] (J.-P.F.) * Correspondence:
[email protected]; Tel.: +43-316-380-5531 Abstract: Reynoutria japonica Houtt. is a critical invasive alien plant in Europe and North America with a drastic impact on native flora. However, R. japonica has medicinal potential, especially as a source of stilbenes. In order to explore the potential of simple extractions of R. japonica, we conducted qualitative and quantitative analyses of fresh R. japonica rhizome infusion, decoction, and macerates with ethanol by UHPLC-DAD-ESI-MSn and UHPLC-DAD, with a focus on major constituent groups of stilbenes and anthranoids. Since R. japonica rhizome extracts showed antimicrobial potential in the past, we also evaluated the antimycobacterial effect of raw R. japonica extracts for the first time against Mycobacterium smegmatis. Of thirty-four characterized substances, six were stilbenes and twelve anthranoids. The main constituents, four trans-stilbenes and eight anthranoids, were quantified in a validated UHPLC-DAD method. The 38% ethanol macerate showed high stilbene (155.078 mg/100 g Citation: Alperth, F.; Melinz, L.; fluid extract) and low anthranoid content (5.420 mg/100 g fluid extract), while decoction showed the Fladerer, J.-P.; Bucar, F. UHPLC µ Analysis of Reynoutria japonica Houtt. highest anthranoids.