Synthesis and antimicrobial evaluation of pogostone and its analogues

Pogostone (PO) is one of the secondary metabolites from Pogostemon cablin (Blanco) Benth. (Lamiaceae), serving as the effective component of the antimicrobial activity. In this study, PO and a series of its analogues were synthesized by the reaction of dehydroacetate and aldehydes in tetrahydrofuran under a nitrogen atmosphere. Their activities against Candida albicans, Gram positive bacteria and Gram negative bacteria were evaluated. The antifungal results demonstrated that PO (MIC ranged from 12 to 97 μg/mL against all strains, MFC ranged from 49 to 97 μg/mL against all strains) and A3 (MIC ranged from 12 to 49, MFC over 195 μg/mL) showed a strong activity against Candida albicans. While A1 (MIC ranged from 49 to 97 μg/mL) and A2 (MIC ranged from 24 to 49 μg/mL) have only shown effect against Guangzhou clinical isolates, the antibacterial results demonstrated that PO and its analogues showed no effects against the tested bacteria strains. This study suggests that pogostone analogues, with the appropriated structure modification, represented a kind of promising antifungal agents.