Medicinal Plants and Phytocompounds: A Potential Source of Novel Antibiofilm Agents - Antibiofilm Agents: From Diagnosis to Treatment and Prevention - page 218

The antibiofilm activity of curcumin (structure 32) against uropathogens using a
standard quantitative biofilm assay revealed a concentration-dependent reduction in
biofilm biomass of uropathogens when treated with curcumin. Curcumin, at 100 g/

mL, efficiently dislodged the biofilm biomass by 52 %, 89 %, 52 %, and 76 % in
E. coli , P. aeruginosa PAO1, P. mirabilis , and S. marcescens , respectively. In
addition, curcumin was found to be very effective in disrupting the mature
(preformed) biofilms of uropathogens. The CLSM images indicated major disrup-
tion in the biofilm architecture as well as reduced thickness in curcumin-treated
mature biofilms of uropathogens. In E. coli , the thickness of the biofilm was
reduced from 16 to 10 ʼ m, whereas in P. mirabilis it was 11 ʼ m in the control
and 6.36

ʼ

m in curcumin-treated biofilm. Likewise, S. marcescens also displayed a
higher reduction from 12 to 3.78

ʼ

m in biofilm thickness (Packiavathy et al. 2012 ).
Six sesquiterpene lactones (SLs) of the goyazensolide and isogoyazensolide type
isolated from the Argentine herb Centratherum punctatum were found to alter
biofilm formation, elastase activity, and production of N -acyl-homoserinelactones
(AHLs) at lower concentrations. Compounds 2, 3, and 5 displayed significant
inhibitory effects on P. aeruginosa biofilm formation at 0.5

ʼ

ʼ g/mL, compound

3 being (1.32 M) the most potent (42 %) (Amaya et al. 2012 ). Lastly, ellagic acid

derivatives from Terminalia chebula showed a significant reduction ( p <

ʼ

0.001) in
QS-regulated production of extracellular virulence factors in P. aeruginosa PAO1.
Biofilm formation and alginate were significantly ( p < 0.05) reduced with

enhanced (20 %) susceptibility to tobramycin (Sarabhai et al. 2013 ).

OH

HO

CH 3 O

CH 3 O

O H

32

7 In Vivo Efficacy of Antibiofilm Agents

Various phytocompounds have been reported to possess antibiofilm activity
in vitro ; however, their in vivo efficacy has not yet been fully explored. The
in vivo use of garlic extracts as a potential therapy for lung infections was reported
by Bjarnsholt et al . ( 2005 ). Mice infected with P. aeruginosa and treated with a
garlic/tobramycin combination showed significantly improved clearing of their
bacterial infections as compared to a placebo control group. Highly effective
antibiofilm activity was observed for fresh Allium sativum extract (fresh garlic
extract, FGE). Fourfold treatment of a P. aeruginosa biofilm with FGE (at 24 h
intervals) resulted in biofilm reduction by 6 log10 units. Moreover, in vivo prophy-
lactic treatment of a mouse model of kidney infection with FGE (35 mg/mL) for