Antiviral effects of Euphobia turicalli, Syzygium aromaticum andPunica granatum extracts on Newcastle disease in vovo

Abstract

Newcastle disease (ND) has been identified as one of the major constraints to rural poultry production in Zimbabwe. It is a highly contagious viral disease that affect many species of birds both domestic and wild. The disease is of great importance due to its mortality rates nearing almost hundred percent therefore leading to severe losses for the farmer. Apart from the high mortality rate, there is loss of quality in the poultry products in the form of weight loss in chickens, production of less numbers of eggs and in some cases production of deformed eggs. Antibiotics and vaccines have been implemented to manage the disease; however, these may be costly for small and rural farmers. Another setback with the use of antibiotics is the emergence of antimicrobial resistance in livestock and in the humans that consume the poultry produce. Traditional medicines have been used as remedies for various ailments in livestock and have proven to be a great alternative to vaccines and antibiotics as there are limited side effects. This study tested the antiviral efficacy of medicinal plant extracts of Euphobia turicalli, Punica granatum and Syzygium aromaticum against ND in chicken embryos. The herbal extracts were tested to find out the the phytochemical composition of each of the plants using water, ethanol and methanol as the solvents of choice. The methanol extracts of Euphobia turicalli, Punica granatum and Syzygium aromaticum were then tested for their antibacterial activity against Staphylococcus aureus using the Kirby-Bauer assay. Aqueous, ethanolic and methanolic extracts of the plants where then tested to observe their antiviral activity against ND in chicken embryos, the hemagglution inhibition assay was used to observe the antibody titre in the allantoic fluid of the eggs. Extracts of all three plants were found to have both antibacterial and antiviral properties; ethanol extracts exhibited the most antiviral activity against S. aureus and ND, respectively.Euphorbia tirucalli tested positive for all the phytochemical investigated, i.e., phenols, flavonoids, alkaloids, saponins, tannins, steroids and glycosidesandP. granatum and S. aromaticum did not have any steroids. E. tirucalli exhibited X stronger antibacterial and antiviral activity against S. aureus (Fig 4.2) and ND (Fig 4.3) than the other two herbal extracts. The ethanolic extracts were more potent with an antibody titre on 2048 in comparison to the aqueous and methanolic extracts that had antibody titres of 1024 and 128 respectively. These findings are of indicate that ethnoveterinary medicines may be a viable alternative to the use of antibiotics and vaccines as a method of treatment for Newcastle disease and suitable candidates for drug development