Download PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... The isolation and synthesis of the racemic form of a novel β-carboline guanidine alkaloid, tiruchanduramine, a potent α-glucosidase inhibitor from the Indian ascidian, Synoicum macroglossum has been achieved. ... The isolation and synthesis of a novel β-carboline guanidine ...