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Author Notes:

Corresponding Author: E-mail: julia.kubanek@biosci.gatech.edu.

We thank the Government of Fiji and the customary fishing right owners for permission to perform research in their territorial waters.

We thank M. E. Hay, T. Waqa, R. X. Poulin, R. Brooker, and K. Feussner for collection of algal samples; D.E Bostwick and C. Sullards for mass spectrometric analyses; L. T. Gelbaum for NMR assistance; A. Burns, J. Mathew-Valayil, and G. O. Longo for antimicrobial assays, and B. K. Chhetri for manuscript revision.

We finally thank Dr. Ronald Quinn for the useful discussions related to the manuscript.

The authors declare no competing financial interest.


Research Funding:

This work was supported by ICBG Grant U19-TW007401 and by NIAID Grant R21 AI136563 from the U.S. National Institutes of Health and the Bill & Melinda Gates Foundation, Seattle, WA (Grant No. OPP1107194).

This research was supported in part through research cyberinfrastructure resources and services provided by the Partnership for an Advanced Computing Environment (PACE) at the Georgia Institute of Technology, Atlanta, GA.


  • oligomeric phenols
  • tetrahydroxy
  • biphenyl
  • synthesized
  • cladophorols
  • Fijian green alga
  • cladophora socialis
  • NMR spectroscopy
  • DFT calculations
  • picric acid
  • overlapping aromatic signals
  • Gram-positive
  • Gram-negative

Antibacterial Oligomeric Polyphenols from the Green Alga Cladophora socialis


Journal Title:

Journal of Organic Chemistry Research


Volume 84, Number 9


, Pages 5035-5045

Type of Work:

Article | Final Publisher PDF


A series of oligomeric phenols including the known natural product 3,4,3′,4′-tetrahydroxy-1,1′-biphenyl (3), the previously synthesized 2,3,8,9-tetrahydroxybenzo[c]chromen-6-one (4), and eight new related natural products, cladophorols B-I (5-12), were isolated from the Fijian green alga Cladophora socialis and identified by a combination of NMR spectroscopy, mass spectrometric analysis, and computational modeling using DFT calculations. J-resolved spectroscopy and line width reduction by picric acid addition aided in resolving the heavily overlapped aromatic signals. A panel of Gram-positive and Gram-negative pathogens used to evaluate pharmacological potential led to the determination that cladophorol C (6) exhibits potent antibiotic activity selective toward methicillin-resistant Staphylococcus aureus (MRSA) with an MIC of 1.4 μg/mL. Cladophorols B (5) and D-H (7-11) had more modest but also selective antibiotic potency. Activities of cladophorols A-I (4-12) were also assessed against the asexual blood stages of Plasmodium falciparum and revealed cladophorols A (4) and B (5) to have modest activity with EC 50 values of 0.7 and 1.9 μg/mL, respectively.

Copyright information:

© 2019 American Chemical Society.

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
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