Fig. 1

Chemical structures of the identified metabolites from C. roseus extract with antibacterial activity. The active fraction from the root extract contained serpentine (a), loganic acid (b) and catharanthine (c); the leaf sample contained vindoline (d) as the most abundant metabolite, followed by loganic acid (b) and serpentine (a). For the experiments in Table 6, ajmalicine (a) and loganin (b) were used as these are commercially available. Glc = glucose