Background: Infectious diseases contribute to substantial mortality and morbidity
worldwide despite advances in therapeutic intervention highlighting the need to identify drugs with
Methods: Here, we utilised several compounds from the following classes: porphyrin, naphthalene
diimide, aminophenol derivatives, and benzodioxane, and evaluated their antibacterial activities.
Bactericidal and bacteriostatic activity of these compounds were determined against methicillinresistant
Staphylococcus aureus (MRSA) and Escherichia coli K1 with various concentrations of
the drugs. Moreover, the ability of the bacteria to bind/associate to host cells was also ascertained
in the absence and presence of aforementioned compounds.
Results: The results revealed that porphyrin derivative (AYTHPP) had potent effects against
MRSA, abolishing viability and blocking binding to the host cells. Importantly, novel AYTHPP
exhibited powerful effects against MRSA even though it was not photoactivated. In contrast, other
compounds, including naphthalene diimide, acetamol derivatives and benzodioxane, showed no
Conclusion: The mechanism of action of porphyrin is likely through the production of reactive
oxygen species causing oxidative stress, leading to apoptosis and/or necrosis via perturbations in
the plasma membrane. Future studies will determine their in vivo efficacy together will associated
molecular mode of action.