Antimicrobial Properties of Natural Furanocoumarins

Furanocoumarins are a kind of organic compounds produced by plants which have diverse effects on many organisms.65 Furanocoumarins, isolated from the Heracleum maximum root extract were identified as anti-mycobacterial compounds. Besides, 6-isopentenyloxyisobergapten was more active than other furanocoumarins by MICs of (167μM) and IC50s of (27 μM) against Mycobacterium tuberculosis that it may be related to isoprenyl group attached to this compound. The antimicrobial activity of 8-geranyloxy psoralen, a furanocoumarin isolated from Prangos uloptera roots, was examined against Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli, Candida glabrata, Candida krusei and Candida kefyr. As well, 8-geranyloxy psoralen showed the most antibacterial activity against Staphylococcus epidermidis by MICs of (100 mgmL-1) and anti-fungal effects against Candida krusei and Candida kefyr, with MICs of (300 and 100 mgmL-1), respectively.66 Razavi et al indicated that furanocoumarins are more effective on gram-positive bacteria.67 Moreover, furocoumarins inhibited auto-inducer (AI) signaling and biofilm formation in bacteria. As well, Girennavar et al isolated furocoumarins from grapefruit and investigated the effect of these natural compounds on different bacterial strains. The results indicated that furocoumarins of grapefruit juice were potent inhibitors of both N-acylhomoserine lactone (AI-1) and molecule, autoinducer-2 (AI-2) activities, while interfere with bacterial growth was not observed.68 Despite many studies exhibited the antimicrobial activity of natural furanocoumarins, recognition of the precise mechanism of these compounds against microbial activity needs more investigations (Figure 3).69–71

Possible pathways that suggested for antimicrobial effects of furan natural derivatives.