Phenolic content and antibacterial activity of cupressus sempervirens leaves extracts against phytopathogenic bacteria pectobacterium atrosepticum causative agent of soft rot on potato and clinical bacteria strains

Abstract

Cupressus sempervirens (Cupressaceae) “cypress” is a specie native to the Mediterranean region. It is a medicinal and an aromatic plant. This study was carried out to evaluate the antibacterial activity of Algerian Cupressus sempervirens leaves extracts against a phytopathogenic bacteria, Pectobacterium atrosepticum, a causative agent of soft rot on potato Solanum tuberosum, and three clinical bacterial strains (Staphylococcus aureus, Escherichia coli and Klebsiella oxytoca), in both cultured media and on potato tubers. Additionally, the Ethanolic, Acetone, and aqueous extracts were investigated for their phenolic content by using the Folin–Ciocalteu assay. The results revealed that all extracts possessed varying antibacterial activities against the tested Gram-positive and Gram-negative bacteria. Pectobacterium atrosepticum was the most susceptible microorganism to all extracts. Similar result of the antibacterial activity of the extracts, using extracts on potato tubers, was obtained. A decrease in soft rot development with almost complete inhibition in presence of extracts was observed. The total phenolic content of the investigated extracts varied from 8.30 ± 0.07 mg GAE / g extract to 27.68 ± 1.20 mg GAE / g of extract. The aqueous extract was the richest in total polyphenols (27.68 ± 1.20mg GAE / g of extract). From the results of this study, it is concluded that the Algerian cypress can be used as an effective natural antibacterial for treating multiple diseases, as well as an excellent biological control against the pathogens of potato rots, and natural food preservative.