Synthesis and antibacterial evaluation of a series of oligorhamnoside derivatives.

A series of novel oligorhamnoside derivatives (1-10) and naturally occurring cleistrioside-5 were synthesized and evaluated for their in vitro antibacterial activities. Among them, dirhamnoside derivative 7 and cleistrioside-5 displayed similar antibacterial profiles and exhibited moderate to good inhibitory activities on bacterial growth against a panel of Gram-positive bacteria (MICs ≤ 4-32 μg/mL). The results revealed that these two compounds showed selectivity towards bacterial species strictly, without being affected by the antibiotic-resistant/susceptible properties of one species, which suggested that they might have the potential to avoid antibiotic cross-resistance. In addition, the preliminary SARs of this type of oligorhamnoside derivatives on the antibacterial activities were determined.