BIOLOGICAL ACTIVITY OF SOME IRRADIATED PLANT EXTRACTS ON SOME PATHOGENIC BACTERIA

Abstract

The present investigation was conducted to evaluate the antibacterial activity of 10 plant and plant by-products: grape (Vitis vinifera), mulberry (Morus alba), mallow (Corchorus olitorius), lemon (Citrus limon), purslane (Portulaca olerace), rosemary (Rosmarinus officinalis L), ficus (Ficus retusa L), black myrobalan (Terminalia chebula), cinnamon (Cinnamomum veru) and ginger (Zingiber officinale) against 45 locally pathogenic bacterial isolated from patients having infectious diseases in some Egyptian hospitals using the agar disc diffusion method. These isolates were identified as Staphylococcus aureus (St1-16), Escherichia coli ( Ec1-10), Pseudomonas aeruginosa (Ps1-15) and Salmonella spp. (Sa1-4). Among 10 ethanolic plant extracts, 4 extracts from leaves of grape, mulberry, mallow and lemon were found to exhibit high potential antimicrobial properties against 45 bacterial isolates. These plants were extracted by different solvents (ethanol, methanol and n-hexane) then irradiated with gamma-radiation doses (5 and 10 kGy) and compared with non-irradiated plants, and result showed that ethanol or methanol extracts were more active than irradiated extracts. Hexane extracts from irradiated or non-irradiated plants had no effect on the pathogenic tested bacteria. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of grape, mulberry, lemon and mallow were determined at concentrations of 2.56 mg/ml to 0.01mg/ml. Four tested ethanolic plant extracts were the