Tannins Possessing Bacteriostatic Effect Impair Pseudomonas aeruginosa Adhesion and Biofilm Formation

Abstract

Plants produce many compounds that are biologically active, either as part of their normal program of growth and development or in response to pathogen attack or stress. Traditionally, Anadenanthera colubrina, Commiphora leptophloeos and Myracrodruon urundeuva have been used by communities in the Brazilian Caatinga to treat several infectious diseases. The ability to impair bacterial adhesion represents an ideal strategy to combat bacterial pathogenesis, because of its importance in the early stages of the infectious process; thus, the search for anti-adherent compounds in plants is a very promising alternative. This study investigated the ability of stem-bark extracts from these three species to control the growth and prevent biofilm formation of Pseudomonas aeruginosa, an important opportunistic pathogen that adheres to surfaces and forms protective biofilms. A kinetic study (0–72 h) demonstrated that the growth of extract-treated bacteria was inhibited up to 9 h after incubation, suggesting a bacteriostatic activity. Transmission electron microscopy and fluorescence microscopy showed both viable and nonviable cells, indicating bacterial membrane damage; crystal violet assay and scanning electron microscopy demonstrated that treatment strongly inhibited biofilm formation during 6 and 24 h and that matrix production remained impaired even after growth was restored, at 24 and 48 h of incubation. Herein, we propose that the identified (condensed and hydrolyzable) tannins are able to inhibit biofilm formation via bacteriostatic properties, damaging the bacterial membrane and hindering matrix production. Our findings demonstrate the importance of this abundant class of Natural Products in higher plants against one of the most challenging issues in the hospital setting: biofilm resilience.

Tannic acid-modified silver nanoparticles for wound healing: the importance of size

“…24,25 Additionally, TA inhibits S. aureus, P. aeruginosa and E. coli biofilm formation in multiple biofilm models. [26][27][28] Bacterial infection is one of the most serious complications impairing wound healing and tissue regeneration, which may lead to prolonged inflammatory responses, and hence it delays wound recovery. Here, we showed that AgNPs modified with TA inhibited bacterial growth more effectively than TA-modified or unmodified AgNPs (Table 1).…”

Antibacterial, antibiofilm, hemolytic activity and phytochemical study of various aerial parts of Moringa oleifera in Pakistan

“…The antimicrobial and antibiofilm activity of various aerial parts of Moringa oleifera was in order: mLe > mBa >mFl>mFr>mSt and these activities were due to the presence of phytochemical compounds like saponins,aterpenoids, alkaloids, carbohydrates, fats, tannins, flavonoids and sterols. The various phytochemicals and secondary metabolites have been reported to exhibited antimicrobial activities (Trentin et al, 2013;Manner et al 2013). The leaf and bark showed highest zone of inhibition at the concentration of 100 µg/disc and as an antibiofilm against bacterial pathogens while at same concentration of 100 µg/dics the other extracts showed least antibacterial and antibiofilm activity against the studied bacteria.…”

Effects of Rainfall on the Antimicrobial Activity and Secondary Metabolites Contents of Leaves and Fruits of Anadenanthera colubrina from Caatinga Area

“…This plant has been subject of several studies about its pharmaceutical potential. [4][5][6][7]12,17 In our previous studies the antimicrobial action of extracts and fractions from leaves and fruits of A. colubrina was reported against Gram-positive bacteria, and no activity was observed against Gram negative bacteria. [4][5][6]12 In the present work we employed a different extraction method, by which we obtained extracts with activity against tested Gram negative bacteria.…”

“…2,3 For some of those, scientific evidences confirm these therapeutic aptitudes. [4][5][6][7] In recent years, the ethnomedicinal knowledge has stimulated several studies about the pharmaceutical potential of natural products of northeastern Brazil. 8 This is justified by the fact that the intrinsic features of Caatinga area (drought, high solar radiation rates and other environmental stresses) influence the synthesis of secondary metabolites of its plants, 9 making them attractive targets for bioprospecting programs.…”