Antimicrobial activity of Brachidontes variabilis extracts against multidrug-resistant bacteria clinically isolated

Resistance to pathogens against kinds of traditional medicines is a public health problem, which calls for the continuous search for new compounds that are effective in eliminating diseases caused by these pathogens. Marine Animals come on top of animals that contain natural treasures of active substances that have not yet been discovered.

In this study, two organic extracts (methanol and ethyl acetate) were prepared from the soft tissue of a marine organism (Brachidontes variabilis). Then, the antioxidant activity and phenol content were determined in these two extracts. Finally, their biological activities were studied toward drug-resistant microbes isolated from Syrian hospitals.

The results showed that the IC50, the concentration required to reduce DPPH radicals by 50%, for methanol and ethyl acetate extracts were 179.286 and 73.676 mg/mL, respectively. The total phenolic contents of the methanol and ethyl acetate extracts were found to be 1.84 mg/g and 1.7 mg/g of the Gallic acid equivalent, respectively. The two extracts had an inhibitory effect on the growth of the following resistant bacterial species isolates: Staphylococcus aureus, Klebsiella pneumonia, Escherichia coli, and Pseudomonas aeruginosa, at a concentration of 5 mg/mL, with inhibitory zones ranging from 5 mm to 20 mm. The ethyl acetate extract has an inhibitory effect on the growth of the fungal pathogen Aspergillus fumigatus, which is resistant to fungal antibiotics.

The results of this study are promising in finding new compounds with antimicrobial effects against resistant pathogens.