Fig. 1 in Alkaloid and iridoid glucosides from Palicourea luxurians (Rubiaceae: Palicoureeae) indicate tryptamine- and tryptophan-iridoid alkaloid formation apart the strictosidine pathway

Fig. 1. Structures of the isolated tryptamine-iridoid alkaloids and the tryptophan-iridoid alkaloid from leaves of Palicourea luxurians: Isoalstrostine A (1), dehydrorudgeifoline (2), alstrostine A (3), javaniside (4) and 5α-carboxystrictosidine (5). The glucoside moieties are shown as D-glycosides for compounds 1 to 5 as well as for all other isolated glycosides 6 to 14a/14b (Fig. 2), but have not been proven in all cases due to low available amounts.