Plant Based Antiamoebic Drugs; Part I. Antiamoebic Activity of Phenanthroindolizidine Alkaloids; Common Structural Determinants of Activity with Emetine

Abstract

Fourteen phenanthroindolizidine alkaloids which differ in number, nature, and distribution of oxygen-bearing substituents, in the presence of unsaturation in ring E or in the presence of an angular (methyl or hydroxyl) function or in the cleaved phenanthrene portion were isolated from two species of Tylophora plant. These along with the synthesized unsubstituted molecule and its intermediates were examined for their amoebicidal activity in vitro and all had been found active with varying MIC's. Structure-activity relationships were deduced and common structural-determinants of this activity with emetine were found. The acute toxicity of tylophorine hydrochloride was determined and the same was found to be equally effective in intestinal as well as hepatic amoebiasis in test animals.