Phloroglucinol-meroterpenoids from the leaves of Eucalyptus camaldulensis Dehnh

Mareena Daus; Suttiwan Wunnoo; Supayang P Voravuthikunchai; Saowanit Saithong; Preeyaporn Poldorn; Siriporn Jungsuttiwong; Natharika Chomlamay; Kanyaluck Yangok; Ramida Watanapokasin; Suda Chakthong

doi:10.1016/j.phytochem.2022.113179

Phloroglucinol-meroterpenoids from the leaves of Eucalyptus camaldulensis Dehnh

Phytochemistry. 2022 Aug:200:113179. doi: 10.1016/j.phytochem.2022.113179. Epub 2022 Apr 6.

Affiliations

¹ Division of Physical Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand; Natural Product Research Center of Excellence, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.
² Natural Product Research Center of Excellence, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand; Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.
³ Natural Product Research Center of Excellence, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand; Center of Antimicrobial Biomaterial Innovation-Southeast Asia, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.
⁴ Division of Physical Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand; Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.
⁵ Department of Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190, Thailand.
⁶ Department of Biochemistry, Faculty of Medicine, Srinakharinwirot University, Sukumvit 23, Bangkok, 10110, Thailand.
⁷ Division of Physical Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand; Natural Product Research Center of Excellence, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand; Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand. Electronic address: suda.ch@psu.ac.th.

PMID: 35398088
DOI: 10.1016/j.phytochem.2022.113179

Abstract

Fourteen undescribed phloroglucinol-meroterpenoids, namely eucalypcamals A-N, were isolated from a CH₂Cl₂ extract of the leaves of Eucalyptus camaldulensis Dehnh. In addition, from the same extract, twelve known phloroglucinols, three known flavonoids, and four known phenolic compounds were also isolated. The structures of the undescribed compounds were analyzed by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, and high resolution electrospray ionization mass spectrometry (HRESIMS). The assignments of the absolute configurations were performed by comparing the experimental electronic circular dichroism (ECD) data with the calculated values. Eucalyprobusal E was found to be cytotoxic against HCT116, Jurkat, and MDA-MB-231 cell lines with IC₅₀ values of 17.6, 9.44, and 17.9 μM, respectively. Eucalrobusone F exhibited antibacterial activity against methicillin-resistant S. aureus (MRSA) and S. aureus with minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC) values of 4/4 μg/mL while euglobal Ia₁ showed antifungal activity with MIC/MFC values of 16/16 μg/mL.

Keywords: Antibacterial; Antifungal; Cytotoxicity; Eucalyptus camaldulensis Dehnh.; Myrtaceae; Phloroglucinol–meroterpenoids.

MeSH terms

Anti-Bacterial Agents / pharmacology
Eucalyptus* / chemistry
Methicillin-Resistant Staphylococcus aureus*
Microbial Sensitivity Tests
Phloroglucinol / chemistry
Plant Extracts / chemistry
Plant Leaves / chemistry
Staphylococcus aureus

Substances

Anti-Bacterial Agents
Plant Extracts
Phloroglucinol