by Julia Samuel on  February 10, 2017 at 1:42 PM Health Watch
  • A compound extracted from a deep-water marine sponge has antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA).
  • MRSA is a drug resistant bacteria to all beta-lactam antibiotics such as methicillin, penicillin, oxacillin and amoxicillin.
  • Dragmacidin G isolated from a marine sponge inhibits the activity of MRSA.

A deep-water marine sponge collected near the Bahamas contains a compound that shows potent antibacterial activity against the drug resistant bacteria methicillin-resistant Staphylococcus aureus (MRSA).

MRSA bacteria are resistant to all beta-lactam antibiotics such as methicillin, penicillin, oxacillin and amoxicillin and can be fatal.
New Compound In Marine Sponge Fights Drug-resistant Bacteria

Researchers have been able to demonstrate the isolation, structure elucidation and biological activity of a new indole (basis of many biologically active substances) alkaloid isolated from a marine sponge. The antibiotic compound "dragmacidin G" shows a broad spectrum of biological activity including inhibition of MRSA as well as a panel of pancreatic cancer cell lines.

"Sponges of the genus Spongosorites, have been a source of a number of biologically active bis-indole alkaloids that are reported to have a variety of activities including antibacterial, antiviral, antifungal, antiplasmodial, cytotoxic as well as anti-inflammatory activities," said Amy Wright, Ph.D., lead author and a research professor at FAU's Harbor Branch who directs the Institute's drug discovery program.

"We found substantial antibacterial activity for dragmacidin G. It is greater than 10-fold more potent than other members of the bis-indole alkaloids while retaining selectivity towards bacterial over mammalian cells."

Over the past 10 years, the team has developed a library of materials (the FAU Harbor Branch-enriched fraction library) that are tested against a variety of diseases both at FAU's Harbor Branch and in partner laboratories.

Once an activity is discovered, the team uses bioassay-directed fractionation to purify the bioactive natural products. The researchers can then define how the compounds work using a wide array of methods such as small molecule immunochemical (affinity) chromatography or in this instance developing bacteria that are resistant to dragmacidin G and then defining what genetic changes are present in the resistant bacteria.

For this study, fractions from the FAU Harbor Branch-enriched fraction library were screened in a number of assays including growth inhibition of the drug-resistant human pathogenic bacteria MRSA.

The structures of these new compounds are determined through spectroscopic means with an emphasis on the use of nuclear magnetic resonance spectroscopy.

The highly enriched fraction containing the new compound showed activity in all three assays and was further purified to obtain pure dragmacidin G, which enabled its structure elucidation and biological testing. The researchers are planning further studies based on these preliminary results.

  1. Amy Wright et al., Compound from deep-water marine sponge could provide antibacterial solutions for MRSA, Marine Drugs (2017).

Source: Medindia

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