Study on antibacterial activities of Hibiscus rosa-sinensis L. Leaf and flower extracts against Proteus mirabilis, Pseudomonas aeruginosa, and Klebsiella pneumoniae

Abstract

Antibiotic resistance of bacterial strains causing serious diseases is one of the major concerns of public health worldwide. Metabolites of plants, particularly higher plants, have been suggested as alternative potential sources for antibacterial products due to their safe. They have little or no side effects and may act at multiple and novel target sites to bacteria. The study aims to evaluate antibacterial activities of leaf and flower extracts and solvent soluble fractions of the extracts against Proteus mirabilis, Pseudomonas aeruginosa, and Klebsiella pneumoniae, the major causes of infection-related kidney stones (struvite stones). Diameters of inhibitory zones, and MIC and MBC values of the extracts and fractions against the bacteria were evaluated. The results showed that the extracts and fractions derived from flowers have activities stronger than those from leaves, especially the ethyl acetate fraction (EtOAc fr.). The inhibitory zone diameters of 10 mg per paper disc of the EtOAC fr. towards Ps. aeruginosa, Pr. mirabilis, and K. pneumoniae were 17, 15 and 13 mm, respectively. The EtOAC fraction. had antibacterial activity against both Ps. aeruginosa and Pr. mirabilis with MIC (MBC) values of 2.5–5.0 (7.5) mg/mL and against K. pneumoniae with MIC (MBC) values of 7.5 (10) mg/mL. The fraction needs to be more studied for identifying its major active constituents. These leaf and flower extracts of H. rosa-sinensis could be used to treat against urinary tract infections caused by multiple drug resistant bacteria.