Physicochemical and Structural Characterization of Sweitenia mycrophylla Gum

Abstract

Sweitenia mycrophylla gum (Mahogany gum) was characterized using standard procedure. The acute toxicity test of the gum on albino mice was determined using standard method. Physicochemical properties such as moisture content, ash content, protein, pH, viscosity, Refractive index, water holding capacity, Specific rotation, swelling index and emulsifying capacity were evaluated. Scanning electron microscopy (SEM), X-ray powdered diffractometry (XRDP), Fourier Transform Infrared (FTIR) and ¹³C Nuclear magnetic resonance (NMR) spectroscopy were used to characterized the gum. Results revealed that the LD50 of the gum in mice is greater than 5000mg/kg. Physicochemical parameters shows moisture content to be 5.70 0.15%, ash content 6.8 0.52%, protein 1.43 0.51%, pH 7.80 0.5, viscosity 28.40 0.30, refractive index 1.34 0.01, water holding capacity 67.20 0.28%, specific rotation -42⁰, swelling index 15.20 0.40 and emulsifying capacity 43.60 0.25%. SEM analysis suggested the gum has irregular particle size. The XRPD pattern of the gum showed no sharp peak confirming a completely armophous structure. FTIR spectrum showed band characteristics of O-H(3650-3500 cm-¹), C-O-C (1632 cm-¹), -COO (1429 cm-¹) groups that are present in the structure of polysaccharide. NMR spectroscopy revealed that the gum is a galactomannan type polysaccharide with mannose/galactose ratio of 2.60. Due to its good physicochemical properties and mannose/galactose ratio, Sweitenia mycrophylla galactomannan could be a useful polysaccharide for food and pharmaceutical industry. Keywords: Sweitenia mycrophylla gum, polysaccharide, SEM, XRPD, NMR, FTIR.