Sustained release of a purified tannin component of Terminalia chebula from a titanium implant surface prevents biofilm formation by Staphylococcus aureus.

Although biofilms are formed on a variety of surfaces, of utmost significance are those formed on prosthetic devices used as implants. Such biofilms can lead to severe device-related infections that are difficult to treat. In a search for new antibiofilm agents that can be used as "active" implant coatings, purified fraction from a tannin-rich extract of Terminalia chebula was isolated and tested for its antibiofilm properties on a titanium implant material. The fraction, named as Fraction 7, was found to significantly reduce biofilm formation by hospital isolates of Staphylococcus aureus, at sub-inhibitory concentrations that were 64 times lower than the minimum inhibitory concentration (MIC). Simulated local delivery systems of the Fraction 7 set upon the surface of titanium alloy released the fraction in a controlled manner from a biodegradable carrier (PDLLA) and were found to significantly reduce biofilm formation by a methicillin-resistant hospital isolate of S. aureus in a load concentration dependent manner without preventing growth. This study therefore identifies a novel fraction from tannin-rich extract of T. chebula that has potential to be used as an antibiofilm coat on implant surfaces.