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A New Phloroglucinol Derivative Isolated from Hypericum afrum, a Plant Endemic to Algeria

Farida Larit, Francisco León, Narayan D. Chaurasiya, Babu L. Tekwani, Samira Benyahia, Samir Benayache and Stephen J.Cutler

Department of BioMolecular Sciences, Division of Medicinal Chemistry, The University of Mississippi, University, MS 38677, United States

Faculté des Sciences Exactes, Département de Chimie, Université Constantine 1, 25000 Constantine, Algeria

National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS 38677, United States

Laboratoire de Synthèse Organique, Modélisation et Optimisation des Procèdes (LOMOP), Université Badji Mokhtar, Faculté des Sciences, Département de Chimie, 23000 Annaba, Algeria

Unité de Recherche Valorisation des Ressources Naturelles, Molécules Bioactives et Analyse Physico-Chimique et Biologique (VARENBIOMOL), Université des Frères Mentouri, Constantine, Algeria

Abstract: A new phloroglucinol derivative, identified as 3-benzoyl-3-hydroxy-5-(3-methylbut-2-en-1-yl)cyclopentane-1,2,4-trione (1 ), together with eight previously reported compounds, quercetin, myricitrin, hypericin, biapeginin, pseudohypericin, myricetin, 1,3,5,6-tetrahydroxyxanthone, and β-sitosterol were isolated from the chloroform, ethyl acetate and butanol extracts of the aerial part of Hypericum afrum (Lam.). Their structures were elucidated by spectroscopic analyses, including 1D-, 2D-NMR and HRESIMS. The EtOAc extract showed moderate MAO-A inhibition with an IC 50 value of 3.35 μg/mL. Bioassay-guided fractionation of the EtOAc extract resulted in the isolation of quercetin as the active component exhibiting MAO-A inhibitory activity with an IC 50 value of 1.25 μM.

Keywords: Hypericum ; phloroglucinol derivatives; MAO-A and MAO-B ; spectroscopic analyses . © 2017 ACG publications. All rights reserved.