Molecular-trapping in Emulsion's Monolayer: A New Strategy for Production and Purification of Bioactive Saponins

Abstract

Saponins from defatted root-extract of Securidaca longipedunculata were systematically entrapped in emulsion monolayer-barrier and finally recovered in pure form through demulsification. First, their molecules were dispersed in water to engineer a monomolecular film architecture, via self-assembly. Emulsifying with ethyl-ether resulted in swollen micelles and engendered phase-inversion and phase-separation, by disrupting the thermodynamic equilibrium. As positive outcome, a Winsor II system was obtained, having saponin-rich upper phase (ethyl-ether) and impurities bound lower phase (aqueous). Saponin particles underwent transition in insoluble ethyl-ether, precipitated and recovered as solids. The entire process was bioactivity-guided and validated using pooled fractions of securidaca saponins, purified by TLC (RP-C18, F254S). TEM and SEM revealed interesting morphologies and particle sizes between nanometer and micron. At the end, purity output of 90% and total recovery of 94% were achieved. Here we show that "molecular-trapping in emulsion's monolayer" is an effective method for recovery, production and purification of saponins of plant origin.