Magnificines A and B, Antimicrobial Marine Alkaloids Featuring a Tetrahydrooxazolo[3,2-a]azepine-2,5( 3H,6H)-dione Backbone from the Red Sea Sponge Negombata magnifica

  • Mar Drugs. 2021 Apr 12;19(4):214. doi: 10.3390/md19040214.
Diaa T A Youssef  1 ,  Hani Z Asfour  2 ,  Grégory Genta-Jouve  3  4 ,  Lamiaa A Shaala  5  6  7
Affiliations
  • 1. Department of Natural Products, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
  • 2. Department of Medical Parasitology, Faculty of Medicine, Princess Al-Jawhara Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
  • 3. UMR 8038 CiTCoM, Faculté de Pharmacie de Paris, Université Paris Descartes, Avenue de l'observatoire, 75006 Paris, France.
  • 4. Molecules of Communication and Adaptation of Microorganisms (UMR 7245), National Museum of Natural History, CNRS, 75231 Paris, France.
  • 5. Natural Products Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
  • 6. Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
  • 7. Suez Canal University Hospital, Suez Canal University, Ismailia 41522, Egypt.
PMID: 33921326 DOI: 10.3390/md19040214
Abstract

Investigation of the Red Sea Sponge Negombata magnifica gave two novel Alkaloids, magnificines A and B (1 and 2) and a new β-ionone derivative, (±)-negombaionone (3), together with the known latrunculin B (4) and 16-epi-latrunculin B (5). The analysis of the NMR and HRESIMS spectra supported the planar structures and the relative configurations of the compounds. The absolute configurations of magnificines A and B were determined by the analysis of the predicted and experimental ECD spectra. Magnificines A and B possess a previously unreported tetrahydrooxazolo[3,2-a]azepine-2,5(3H,6H)-dione backbone and represent the first natural compounds in this class. (±)-Negombaionone is the first β-ionone of a Sponge origin. Compounds 1-3 displayed selective activity against Escherichia coli in a disk diffusion assay with inhibition zones up to 22 mm at a concentration of 50 µg/disc and with MIC values down to 8.0 µM. Latrunculin B and 16-epi-latrunculin B inhibited the growth of HeLa cells with IC50 values down to 1.4 µM.

Keywords
(±)-negombaionone; E. coli; HeLa cells; Negombata magnifica; Red Sea sponge; antimicrobial activity; cell line growth inhibition; latrunculin B and 16-epi-latrunculin B; magnificines A and B; marine alkaloids; β-ionone.
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