Flourensia retinophylla: An outstanding plant from northern Mexico with antibacterial activity

Abstract

Urinary tract infections (UTIs) represent a serious health problem worldwide and are the third most common infectious disease in Mexico. With the excessive use of antibiotics, bacterial species are becoming resistant to drugs prescribed to treat UTIs. These factors have attracted the attention of researchers toward identifying natural antibiotic compounds obtained from plants that provide similar antibacterial activity. Flourensia retinophylla S.F. Blake is an endemic plant from the semi-arid zones of Mexico that has been reported to produce bioactive compounds. Therefore, the aims of this study were to evaluate the in vitro antibacterial activity of the F. retinophylla extract against six bacterial species that cause UTIs: Enterobacter aerogenes, Escherichia coli, Proteus hauseri, Proteus mirabilis, Proteus vulgaris, and Staphylococus epidermidis, and identify the chemical compounds in the extract. The extract was obtained using procedures such as agitating with ethanol, evaluating phytochemicals for total phenolic and flavonoid contents (TPC and TFC, respectively), determining antioxidant activity, and analyzing chemical composition using gas chromatography-mass spectrometry. Antibacterial activity was evaluated in vitro for the six bacterial species. The results showed a TPC of 78.6 mg of gallic acid equivalent/100 mg of extract and a TFC of 47.1 mg of (+)-catechin equivalent/100 mg of extract with antioxidant activity of 86.8%. Moreover, the extract exhibited remarkable antibacterial activity, with a range of minimal inhibitory concentrations for 90% bacteria (MICs90) from 50 to 156.2 mg/L, with values lower than those obtained with penicillin G on E. aerogenes, P. hauseri, P. mirabilis, and S. epidermidis. F. retinophylla leaf extract showed noteworthy bactericidal activity by inhibiting the growth of all six pathogenic bacterial species causing UTIs, mainly E. aerogenes, P. hauseri, and P. mirabilis.