An efficient synthesis and biological evaluation of novel analogues of natural product Cephalandole A: A new class of antimicrobial and antiplatelet agents.

Cephalandole A 2, a small indole alkaloid isolated from the Taiwanese orchid Cephalanceropsis gracilis (Orchidaceae), exhibits anticancer activity. Surprisingly, this natural product has not been evaluated for any other biological activity so far. To discover other novel potential of Cephalandole A 2, an efficient and economic synthetic protocol for novel Cephalandole A analogues 21a-o has been developed, in only 3 steps from using indole, and applied for their biological activity. Biological testing showed that Cephalandole A 2 and its novel analogues 21a-o exhibited potential antimicrobial and antiplatelet activity in preliminary assay. To the best of our knowledge, this is the first report of Cephalandole A 2 and its novel synthetic analogues 21a-o as a new class of antimicrobial and antiplatelet agents. In this study, 2 and other analogues i.e., 21b, 21d, 21i and 21o showed promising antimicrobial activity against the phytopathogenic bacteria and fungi. Cephalandole A 2, 21c, 21f and 21i, also showed potent antiplatelet activity.