مشخصات پژوهش

Recently, the emergence and spread of pathogenic bacterial resistance to many synthetic antibiotics have been increasing throughout the world. This phenomenon is of great concern and there is a need to find new compounds as an appropriate alternative to antibiotics. In this regard, natural antibiotics derived from medicinal plants, some of which have been used in traditional medicine for centuries and have competitive effects compared to some commercial antibiotics, can be studied as alternatives [1-2]. In this study, the antibacterial and antioxidant activities as well as total phenol and flavonoid contents were assayed in the ethanolic extracts obtained by ultrasound-assisted extraction method (UAE) from Terminalia chebula, Rosa canina, and Nigella sativa. The ethanolic extracts were screened against two gram-negative (Escherichia coli ATCC25922 and Pseudomonas aeruginosa ATCC27853( and two gram- positive (Bacillus cereus ATCC11778 and Bacillus subtilis ATCC6633) bacteria with the disk diffusion method. The highest antibacterial potentiality was exhibited by the ethanolic extract of N. sativa against E. coli (16.5 mm). The ethanolic extracts were assessed for their antioxidant activity using DPPH radical scavenging assay. According to the results, the highest antioxidant activity related to T. chebula with the percentage inhibitory of 80.66%. Also, ethanolic extract of T. chebula (140.53 mg GAE/ g plant) showed the highest phenolic content. The highest amount of total flavonoid content was observed in N. sativa extract (11.88 mg QE/g plant). So, T. chebula can be used in food, medicine, and cosmetic industries.