Purification, Structural Characterization and Immunomodulation Properties of Polysaccharides Isolated from Frankincense (Boswellia carterii)

Abstract

Medicinal plants have long been a focus of pharmacological research. Recently there has been an increased interest in the medicinal properties of polysaccharides. These compounds are of interest since many of them have shown high antioxidant, anticancer and immunomodulatory activities with low toxicity. This research focuses on isolation and characterization of polysaccharides from frankincense (Boswellia carterii). Water-soluble polysaccharides were extracted from frankincense and the resulting mixture separated by ion exchange chromatography on a Hi-Prep DEAE-Sepharose Fast Flow column. The individual peaks were further chromatographed using size exclusion chromatography on a Superdex-200 column. This resulted in a total of six polysaccharides, FA1, FA2, FA3, FA4, FA5, and FA6. The purity and molecular weight of each fraction was determined by analytical size exclusion chromatography on a TOSOH TSK gel G4000PWxl column. The fractions were subjected to acid hydrolysis and the released monosaccharides determined by HPLC analysis of the phenyl methyl pyrazolone (PMP) derivatives and GC analysis of the trimethylsilyl derivatives. The isolated polysaccharides were examined for immunostimulatory activity. All the tested polysaccharides showed low toxicity and some degree of immunomodulatory activity. FA2 was found to be the most bioactive fraction followed by FA1 and FA3. The results indicate the possibility of using frankincense polysaccharides as potent immunostimulatory supplements as well as adjuvants.