Abstract

TILIA CORDATA: A POTENT INHIBITOR OF GROWTH AND BIOFILM FORMATION OF BACTERIAL CLINICAL ISOLATES

Ahmad Ismail, Farah Hneini and Tarek Nawas*

Abstract

Residents and herbalists residing in Lebanese mountain areas, noticed that tea preparations of Tilia cordata, a tree that commonly grows there, alleviated symptoms of respiratory tract and throat infections. This study aimed at determining whether Tilia cordata actually was capable of inhibiting the growth of various local clinical bacterial isolates, with particular interest on those that commonly caused respiratory tract infections. Using the agar diffusion method, the results showed that Gram positive bacteria were mainly sensitive to low concentrations of the aqueous extract of Tilia cordata’s flower. Bract aqueous extracts did not inhibit any of the tested isolates. Using the agar dilution method, it was noted that the methanolic flower and bract extracts significantly inhibited the growth of the tested bacterial isolates when the ratios of extracts to media were 0.05 and 0.1. All the isolates were, however, completely inhibited when that ratio was 0.15. The methanolic extract of the flower, at a lower concentration, was also capable of inhibiting the ability of the isolates to form biofilms. The active ingredients of Tilia cordata, if identified, purified, and evaluated for their safety, can prove to be potent antibacterial agents.

Keywords: Antibacterial compounds; Bacterial infections; Herbalism; Medicinal plants; Plant extracts; Tilia cordata.