Medicinal Plants and Phytocompounds: A Potential Source of Novel Antibiofilm Agents - Antibiofilm Agents: From Diagnosis to Treatment and Prevention - page 210

eugenol (structure 1) were investigated for inhibiting Listeria monocytogenes
biofilm formation and inactivating mature biofilms at 37, 25, and 4 C on polysty-
rene plates and stainless-steel coupons. All compounds inhibited biofilm synthesis
and inactivated fully formed Listeria monocytogenes biofilms on both matrices at
all temperatures tested ( P <

0.05). Real-time quantitative PCR data revealed that
all compounds tested downregulated critical Listeria monocytogenes biofilm-
associated genes ( P < 0.05). Kaurenoic acid (KA), a single chemical compound

from A. continentalis, was investigated for its inhibitory effect on the ability of
S. mutans to adhere to saliva-coated hydroxyapatite beads (S-HAs) and biofilm
formation. The adherence of S. mutans was significantly inhibited in a dose-
dependent manner in the presence of KA. In addition, the adherence to S-HAs
was obviously inhibited at 3-4

ʼ g/mL of KA. Biofilm formation was significantly

inhibited at 3 g/mL of KA. Biofilm

formation on the surface of resin teeth was also significantly inhibited when treated
with 3

ʼ g/mL of KA and completely inhibited at 4 ʼ

ʼ g/mL of KA and completely inhibited at 4 ʼ g/mL (Jeong et al. 2013 ).

O

H

18

4 Inhibitors of Fungal Biofilm

Xanthorrhizol isolated from Curcuma xanthorrhiza (Rukayadi et al. 2011 ) and the
oil of Ocimum americanum (Thaweboon and Thaweboon 2009 ) showed potent
in vitro activity against Candida biofilms. In 2008, 30 plant oils including
10 terpenic derivatives and corresponding to the major components of essential
oils were tested for their activity against C. albicans biofilms (Agarwal et al. 2008 ).
Almost all the studied terpenic derivatives showed antibiofilm activity; however,
carvacrol, geraniol, and thymol exhibited the strongest activity. Moreover, these
compounds also proved to be efficient against biofilms of C. glabrata and
C. parapsilosis (Dalleau et al. 2008 ). Polyphenols, extracted from green tea, also
showed effects against C. albicans biofilms. Epigallocatechin-3-gallate (structure
19), the most abundant polyphenol in green tea extract, reduced the C. albicans
biofilm metabolic activity by 80 % (Xie and Lou 2008 ). (R)-goniothalamin, the
most abundant styryl lactone in the Goniothalamus genus ( Annonaceae family),
was active against C. albicans biofilms (Martins et al. 2009 ). Peppermint, eucalyp-
tus, ginger grass, and clove oils resulted in a reduction in C. albicans biofilm
formation. The main component of eucalyptus oil, 1,8- cineole, showed potent
antibiofilm activity against C. albicans biofilms (Hendry et al. 2009 ). Candida