Structure-activity relationship of calanthoside Part 2: positional effects of indole ring substitution on HFDPC proliferation.

Calanthoside (1), an indole S,O-bisdesmoside isolated from Calanthe species, promotes proliferation of human hair follicle dermal papilla cells more effectively than minoxidil. Synthesis and evaluation of ten analogues of 1 with various indole substituents revealed that the 5-chloro analogue (13b) exhibited markedly enhanced proliferative activity relative to 1, highlighting the position-specific beneficial effect of 5-chlorination.