RAGAB I. ABD EL-FATTAH AND MAHA A. AZB*
Botany Department, Faculty of Science, Zagazig University, Zagazig 44519, Egypt
*(e-mail : res.mahaadel@yahoo.com; Mobile : 201000465180)
(Received : July 24, 2019; Accepted : August 22, 2019)
ABSTRACT
This study aimed at examine the antioxidant and antibacterial activity of the aqueous extract of Deverra tortuosa and ZnO nanoparticles synthesized using this extract. The concentration of flavonoids and total phenolics were estimated. The flavonoid content estimated about half of the total phenols. The antioxidant activity was evaluated using the DPPH assay. The aqueous extract had higher antioxidant activities compared with ZnO.NPs in means of EC50 values. The antibacterial activity was tested against two grampositive bacteria (Staphylococcus aureus and Streptococcus mutans) and two gram-negative bacteria (Klebsiella pneumoniae and Salmonella typhimurium) bacteria using the agar disc diffusion method. The inhibitory response was concentration dependent and the MIC varied according to the treatment and bacterial type. ZnO.NPs showed better antibacterial activity against both Gram +ve and Gram ve bacteria than aqueous extract of D. tortuosa. The extract was least effective on Salmonella typhimurium. MIC values were found minimum against Gram +ve S. aureus and the Gram ve S. typhimurium followed by the K. pneumoniae. Highest MIC values (125 µg/ml) were obtained by the plant extract against Gram ve followed by S. aureus.
Key words : Deverra tortuosa, ZnO.NPs, antioxidant activity, antibacterial activity