Phytochemical evaluation and antibacterial effects of Medicago sativa, Onosma sericeum, Parietaria judaica L., Phlomis persica and Echinophora platyloba DC. on Enterococcus faecalis

Abstract

Background: Since drug resistance has become one of the predominant problems of health worldwide, it is necessary to use new methods to combat drug-resistant bacteria. In this regard, medicinal plants are considered one of the richest sources to produce antibiotics. The aim of this study was to investigate the antibacterial effects as well as total phenolic and flavonoid contents of a number of medicinal plants collected from the Chaharmahal and Bakhtiari provinces of India, in order to investigate their potential use for the production of new antibiotics.
 Materials and Methods: In this experimental study, the maceration method was used to prepare hydroalcoholic extract of Medicago sativa, Onosma sericeum, Parietaria judaica L., Phlomis persica and Echinophora platyloba DC. The effect of these plants on Enterococcus faecalis (ATCC 29212) was investigated. To determine the antibacterial effect of the extracts, broth microdilution in sterile 96-well plate was used according to the McFarland standard (105 CFU/ml). The total phenolic content was assayed by using the Folin-Ciocalteu colorimetric method and expressed in terms of gallic acid equivalent. The total flavonoid content was assayed by aluminum chloride colorimetric method and expressed in terms of rutin equivalent.
 Results: Based on the results of this study, the 512, 256, 128, 32 and 32 µg/ml doses were determined to be the minimum inhibitory concentrations (MICs), and the 1024, 1024, 512, 128 and 128 μg/ml doses were derived as the minimum bactericidal concentration (MBCs) of M. sativa, O. Sericeum, P. judaica, P. persica and E. platyloba, respectively. E. faecalis and P. judaica contained the highest total phenolic content and flavonoid content, respectively.
 Conclusion: Given the comparatively higher antibacterial effect of P. persica and E. platyloba, as well as the presence of phenolic and flavonoid compounds in these plants, it is recommended that these plants be further investigated in feasibility studies for the production of new antibiotics.