Jornal de Patologia Vegetal e Microbiologia

Abstrato

Preliminary Studies on Antibacterial and Antiviral Activities of Five Medicinal Plants

Abdel-Shafi S

It is of interest to inhibit the pathogenic bacteria and virus by medicinal plants. This method is safe and cheap. The antimicrobial activities of aqueous infusion and decoction of five medicinal plants: Nigella sativa (NS), Zingiber officinale, Thymus vulgaris, Syzygium aromaticum, Mentha piperita were investigated. The screening of antibacterial activity was against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Listeria monocytogenes, Lactococcus lactis and Bacillus cereus. The aqueous infusion of ginger exhibited maximum activity against E. coli with 15.00 mm inhibition zone (IZ). Also, the infusion of black seeds showed highest antibacterial activity against Lactococcus lactis, P. aeruginosa, L. monocytogenes, and Staphylococcus aureus with 22.30, 9.60, 9.50 and 9.00 mm IZ, respectively. The decoction of peppermint exhibited significant inhibition against E. coli and Lactococcus lactis (20 and 19.5 mm, respectively), while decoction of black seeds showed maximum inhibition against P. aeruginosa and B. cereus with 9.50 and 9.3 mm. The decoction of clove inhibited L. monocytogenes and Staphylococcus aureus significantly compared to other plants. Further antiviral screening was done. The effect of NS extracts as inhibitors against Zucchini yellow mosaic virus (ZYMV) infectivity in-vitro and in-vivo was studied. Aqueous decoction and infusion of NS inhibit the production of ZYMV symptoms on squash plants by 85% and 80%, respectively, in vitro treatment. Upon using of NS infusion and decoction, the phenolic compounds, the total protein as well as peroxidase and polyphenol oxidases were increased, comparing to viral controls. The infusion and decoction of medicinal plants were effective against tested virus and bacteria.