In vivo and In vitro Antimicrobial Effects of Natural Antibiotics Present in Crude Extracts of Various Medicinal Plants

Abstract

Bacteria are among the most common causes of severe diseases in both plants and animals. Salmonella spp. has deleterious effects and is the cause of various transmittable diseases. Because of strains resistivity, side effects and high prices of synthetic antibiotics, it has become essential to explore safe and economical natural sources of antibiotics. In this study, growth inhibitory effects of natural antibiotics present in crude extracts of Galla rhois, Thujae semen, Paeonia japonica, and Armeniacae semen were investigated both in vivo and iv vitro. Ethanol extracts of the above-mentioned plants were prepared and tested against seven serovars of Salmonella and Escherichia coli by disc diffusion method. In addition, the antibacterial effects of the plant extracts were determined in vivo using ducks as model animals. Reverse transcription-polymerase chain reaction was performed using blood and fecal samples of control, infected, and treated groups of the ducks to determine the gene expression levels of the bacteria. Our results confirmed that the Galla rhois ethanol extract had the highest antibacterial activity among the plant extracts when they were used individually. However, the Galla rhois, Thujae semen, and P. japonica ethanol extracts showed stronger antibacterial effects against all the bacterial species used when the extracts were combined at a ratio of 3:3:2, respectively.