Marine algae represent an important source of novel natural products. While their bioactive potential has been studied to some extent, limited information is available on marine algae from the Red Sea. This study aimed at the broad discovery of new bioactivities from a collection of twelve macroalgal species from the Central Red Sea. We used imaging-based High-Content Screening (HCS) with a diverse spectrum of cellular markers for detailed cytological profiling of fractionated algal extracts. The cytological profiles for 3 out of 60 algal fractions clustered closely to reference inhibitors and showed strong inhibitory activities on the HIV-1 reverse transcriptase in a single-enzyme biochemical assay, validating the suggested biological target. Subsequent chemical profiling of the active fractions of two brown algal species by ultra-high resolution mass spectrometry (FT-ICR-MS) revealed possible candidate molecules. A database query of these molecules led us to groups of compounds with structural similarities, which are suggested to be responsible for the observed activity. Our work demonstrates the versatility and power of cytological profiling for the bioprospecting of unknown biological resources and highlights Red Sea algae as a source of bioactives that may serve as a starting point for further studies.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The following reagents were obtained through the NIH AIDS Reagent Program, Division of AIDS, NIAID, NIH: HeLa cells, D4T, DDI, Emtricitabine, beta-D-N4hydroxycytidine, and ddC. Research reported in this publication was supported by the King Abdullah University of Science and Technology (KAUST). We thank Horst Wolff (Carl Zeiss Microscopy, Germany) and Birgit Kraus (University of Regensburg, Germany) for assistance in the setup of the screening panels and imaging software. We would also like to thank Sami Alqarawi and the KAUST Bioscience Core lab for assistance.