Isolation and Characterization of a Lectin-like Protein (SBLP) from the Dried Roots of Scutellaria baicalensis (Lamiaceae)

Abstract

A novel lectin-like protein with MW 63.2 kDa, designated as SBLP, has been isolated and characterized from the dried roots of Scutellaria baicalensis Georgi (Lamiaceae). SBLP was purified by ammonium sulfate precipitation and anion exchange chromatography. It is a glycoprotein according to a PAS staining assay and consisting of protein (86.0%) and sugar (14.0%). Its N-terminal amino acid sequence was determined as GSAVGFLY by Edman degradation. SBLP showed hemagglutinating activity against human and rooster erythrocytes, which were stable below 60°C and in the pH range of 4 −10. Furthermore, SBLP was found to be stimulated by Ca²⁺, Na⁺, Ba²⁺, Zn²⁺ ions, which suggested it was a metal-dependent lectin. SBLP inhibited the growth of Fusarium oxysporum f.sp. lycopersici and Alternaria eichhorniae in the a dose-dependent manner, and suppressed the proliferation of HepG2 tumor cells with an IC₅₀ of 1.00 μM. This is the first report of a lectin from Radix Scutellariae.