Biological activities and structural characterisation of anticancer herbal polysaccharides

Abstract

In recent years, medicinal plants have become popular for the treatment of several diseases due to their efficacy and cost effectiveness. Plant derived therapeutic agents are increasingly sought out as pharmaceuticals for the treatment of life-threatening illnesses. Important contributions have already been made in the recent years to the drug market by the compounds isolated from natural sources or from their derivatives. There is no doubt that, novel lifesaving drugs could be discovered by a systematic evaluation of ethno medicinal information using modern scientific tools. This thesis attempts to systematically combine ethnomedicinal knowledge together with the contemporary scientific methods to evaluate immunomodulatory and anticancer properties of sixteen traditional medicinal herbs with an aim to discover anticancer formulations. The major objective of this project is to isolate and characterise potent anticancer polysaccharides from Traditional Chinese Medicinal (TCM) herbs. In order to achieve these objectives, sixteen Chinese Medicinal herbs have been successfully screened for their antioxidant, immunomodulatory and anticancer activities. Based on their immunomodulatory and anticancer activities, three traditional anticancer TCM herbs, namely, Amauroderma rugosum, Lobelia chinensis and Artemisia annua have been selected for further studies. Isolation and characterisation of polysaccharides from these three medicinal herbs has been carried out. The structural characterization employing FT-IR and NMR spectroscopy has been carried out and presented in Chapters 5 to 7. A total of eight potent immuno-therepuritic polysaccharides have been discovered for the first time from the three important anticancer TCM herbs (A. annua, L. chinensis and A. rugosum). The structure of three of them have been determined. The MRI contrast potentials of Gd(III) complexes of three of the herbal polysaccharides have also been studied. Low molecular weight polysacchro-proteins were found to be T1 agents and high molecular weight polysacchro-proteins were T2 agents. Findings of this thesis have contributed significant scientific knowledge that has offered some suggestions for designing new immuno-therepeutic formulations based on the eight polysaccharides discovered in this thesis. However, further research is required in order to design such formulations.

Date of Award	2017
Original language	English