Evaluation of the Antibacterial and Antioxidant properties of the Methanolic extracts of four Medicinal plants selected from Wadi Al-Karak, Jordan related to their Phenolic contents

Abstract

In this study, the methanolic extracts from four medicinal plants (Sarcopoterium spinosum, Paronychia argentea, Inula viscosa, and Achillea fragrantissima) were tested in vitro for antibacterial and antioxidant properties. The antibacterial properties of these MPEs were assessed using disc diffusion and Serial dilution techniques. The antioxidant properties were evaluated by DPPH and FRAP methods. The total phenolic compounds were measured according to Folin-Ciocalteu method. Differences were found among the tested plants in their antibacterial and antioxidant properties as well as the phenolic content. Among the four plants, I. viscosa revealed the highest antibacterial effects against all bacterial species under examination followed by S. spinosum. Gram-positive bacteria showed higher susceptibility to the MPEs than Gram-negative bacteria. Antioxidant capacity and polyphenolic content investigations revealed that S. spinosum and I. viscosa have the highest antioxidant activities and the highest amount of phenolic compounds. Moreover, a strong positive linear correlation was found between antioxidant activity and total phenolic content. In conclusion, the MPEs of I. viscosa and S. spinosum have been proven to have good antibacterial and antioxidant activities which were highly related to their contents of phenolic compounds. These plant extracts could be interesting sources for natural antibacterial and antioxidant agents.