Oxygenated heterocyclic metabolites with dual cyclooxygenase-2 and 5-lipoxygenase inhibitory potentials from Rhizophora annamalayana
Previously undescribed oxygenated heterocyclic metabolites were purified from the ethyl acetate fraction of natural mangrove hybrid Rhizophora annamalayana. The purified metabolites were characterized as 11-(tetrahydro-14α-hydroxy-13β-methylfuran-12-yl)-10β-methylbutyl benzoate (1), 13-(tetrahydro-15β,16α-dimethyl-18-oxo-2H-pyran-14-yl)-10β-methylhept-12(E)-enyl benzoate (2), and dihydro-11-((7E)-2-hydroxy-8β-methyl-2H-chromen-9-yl)-13-methylpent-12(E)-enyl)-17β-methylfuran-19(3H)-one (3) by the combined spectroscopic experiments. These metabolites were assessed for their antioxidant and anti-inflammatory activities, and compared with the commercially available standards. The purified compound 3 exhibited greater antioxidant activities as deduced by 2, 2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid and 2, 2-diphenyl-1-picrylhydrazyl quenching properties (IC50 2.10 and 2.22 mM, respectively) compared to the positive control (α-tocopherol, IC50 1.46 and 1.69 mM, respectively). Consequently, the anti-inflammatory activity of compound 3 with regard to the inhibitory property towards pro-inflammatory 5-lipoxygenase was greater (IC50 2.16 mM) than that exhibited by the synthetic anti-inflammatory drug ibuprofen (IC50 4.51 mM). Electronic and hydrophobic parameters were deduced to find the target bioactivities of the studied compounds. These oxygenated heterocyclic metabolites could be used as potential therapeutic lead compounds in the pharmaceutical applications.
KeywordsRhizophora annamalayana Rhizophoraceae Natural hybrid mangrove Oxygenated heterocyclic metabolites Antioxidative Anti-inflammatory
This research was supported by the Indian Council of Agricultural Research (ICAR) Network Project High-Value Compounds (grant no. HVC/ICAR 2012–2017). We thank the Director, Central Marine Fisheries Research Institute for support. Thanks are due to the Head, Marine Biotechnology Division, Central Marine Fisheries Research Institute for facilitating the research activity. VR wishes to acknowledge ICAR, for the award of a scholarship.
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Conflict of interest
The authors declare that they have no conflict of interest.
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