The Antibacterial and Antioxidant properties of Methanolic extracts of Selected Medicinal Plants in Jordanian Folk Medicine in Relation to their Phenolic content

Abstract

The aim of this study was to explore the antibacterial and antioxidant properties of methanolic extracts obtained from seven distinct medicinal plants, namely Phlomis brachyodon, Salvia dominica, Hypericum triquetrifolium, Origanum majorana, Foeniculum vulgare, Glycyrrhiza glabra, and Curcuma longa. To assess antibacterial activity, the study employed in vitro testing methods such as disc diffusion and serial dilution techniques. Simultaneously, antioxidant capacity was evaluated using the DPPH and FRAP methods, while the quantification of total phenolic compounds was performed utilizing the Folin-Ciocalteu method. The findings unveiled notable variations in the antibacterial and antioxidant properties, as well as phenolic content, among the tested plant extracts. Among the seven plants investigated, H. triquetrifolium demonstrated the most potent antibacterial effects against all tested bacterial strains, closely followed by S. dominica. Intriguingly, the methanolic extracts exhibited a higher susceptibility of Gram-positive bacteria in comparison to Gram-negative ones. Additionally, the exploration of antioxidant capacity and polyphenolic content revealed that H. triquetrifolium show cased the highest levels of antioxidant activity and contained the greatest quantity of phenolic compounds (422±20mg GA/g dry extract). Furthermore, a positive linear correlation was established between antioxidant activity and total phenolic content. In summary, the methanolic extracts sourced from H. triquetrifolium exhibit substantial potential as natural reservoirs for effective antibacterial and antioxidant agents.