Urtica dioica Agglutinin (UDA) – Separation and Quantification of Individual Isolectins by Reversed Phase High Performance Liquid Chromatography

Summary Stinging nettle (Urtica dioica and Urtica urens) roots are traditionally used as a remedy against BPH in Europe, and one of the plant's active principle discussed is UDA (a mixture of different isolectins). This paper reports on the first HPLC-method permitting the qualitative and quantitative analysis of individual isolectins in Urtica plant material. Optimum results were obtained by using a cyano column, and a mobile phase comprising of 10 mM phosphate buffer (pH 6.75) and acetonitrile. Temperature and detection wavelength were adjusted to 25 °C and 228 nm, respectively. The method was successfully validated for linearity, accuracy and precision. Several U. dioica samples were analysed, and except for one, all contained lectins (isolectins II, I, V and VI in varying composition). Individual compounds were assigned by comparison with reference material or based on data obtained from LC-MS experiments. The quantitative results showed variations in the lectin content from 0.016 to 0.401%; in three commercial products, which were additionally analyzed, no lectins were found.