Abstract

SURFACTANT CHARACTERIZATION OF CRUDE SAPONIN EXTRACTS OF GUAIACUM OFFICINALE LEAF AND STEM

Jayesh Patil*, Janaky Narayanan and Usha Mukudan

Abstract

Saponins are secondary metabolites that are produced by plants and some lower marine invertebrates. Because of their amphiphilic chemical structure, saponins exhibit surface activity similar to that of surfactants and are, therefore, known as natural detergents. Over 100 families of plants include species that are known to contain saponins. Many plant-derived saponins are currently used as emulsifiers in food and beverage and cosmeceutical industries. In the present article, crude saponin extracts of the leaf and stem of Guaiacum officinale (Zygophyllaceae) were characterized for their potential surfactant activity. The leaf and stem extracts reduced the surface tension of water from 72.8 mN m−1 to 49.584 mN m−1 and 49.875 mN m−1, respectively. Additionally, the critical micelle concentration for the leaf and stem extracts was identical (0.037 g L−1). The surface density of micelles for leaf and stem extracts was 0.119 nmol cm−2and 0.121nmol cm−2, respectively. The areas per head group were 139.75 Å2 and 137.49 Å2 for the leaf and stem extracts, respectively. The micellar hydrodynamic radii for the leaf and stem extracts were 18.62 nm and 18.98 nm, respectively. The zeta potential values of the leaf and stem extracts were −15.83 mV and −17.53 mV, respectively. Based on these results, we conclude that crude saponin extracted from Guaiacum officinale leaves and stems have potential application as biosurfactants.

Keywords: Guaiacum, saponin, surfactant, biosurfactant.