Air-assisted dispersive liquid phase microextraction coupled chromatography quantification for purification of therapeutic lectin from aloe vera – A potential COVID-19 immune booster

•Four switchable natural low transition temperature mixtures synthesized.•Lectin isolated by Air assisted Dispersive liquid phase microextraction.•Preparative purification of lectin by gel filtration chromatography done.•Antioxidant and Haemagglutination activity determined for ultrapure lectin.•Kinetics and thermodynamics of the extraction validated with model equation. The present research focuses on devising air assisted liquid phase microextraction coupled chromatographic quantification method for purification of therapeutic lectin using switchable low transition temperature mixtures. Four switchable low transition temperature mixtures were formed by mixing benzyl trimethyl ammonium chloride with sodium salts of various heavy chain fatty acids in the molar ratio of 1:1. Thermophysical properties (Density, Refractive index and surface tension) were determined as a function of temperature. Air-assisted dispersive liquid-phase microextraction with switchable solvents was carried out to obtain lectin rich concentrate in top phase with an extraction efficiency of (85% w/w). The purified lectin was quantified by size exclusion chromatography with the retention time of 2.3 min and resolution of 6.2 with NTU of 13.2. The ultrapure fraction of lectin was obtained with anion exchange chromatography yielding antioxidant activity of 40.2 mg GAE/g lectin and haemagglutination activity of 45.36 HU/g in the isolate. The method of dispersive liquid-phase microextraction provides a high selective one-pot extraction and partial purification of the therapeutic lectin from aloe vera.