Macrocarpal-like Compounds fromEugenia umbellifloraFruits and Their Antibacterial Activity

Abstract

Certain members of the genus Eugenia are used as foods. One of these species is Eugenia umbelliflora, which is used for its fruits. The aim of the study was to isolate the constituents of the CH2Cl2 fraction obtained from E. umbelliflora O. Berg (Myrtaceae) and also to evaluate its antimicrobial properties. Two new meroterpenoids, eugenial C (3) and eugenial D (4) were isolated from the unripe fruits of E. umbelliflora and their structures established mainly by extensive NMR spectroscopy. In previous studies, the CH2Cl2 extract showed significant antibacterial activity, which can be attributed to meroterpenoids isolated in this study. The compounds eugenials C and D exhibited potent activity against Bacillus subtilis and Staphylococcus aureus and different strains of MRSA and activity similar to those of the antibiotics used in antimicrobial therapies.

In silico and in vitro degradation studies of isolated phloroglucinols eugenial C and eugenial D from Eugenia umbelliflora fruits

“…The multiplicity of a particular signal was indicated as s (singlet), d (doublet), t (triplet), or m (multiplet). The chemical structure was confirmed with data from the literature . The spectra of eugenial C and eugenial D are shown in the Supporting Information (Figures S1 and S2, respectively).…”

“…A voucher specimen (VC Filho 50) was deposited at the Barbosa Rodrigues Herbarium, Itajaí, Brazil. The complete procedure used for obtaining eugenials C and D, from the fruits of E. umbelliflora , was described previously by Faqueti et al . Briefly, the dried and shop bought fruits (860 g) were extracted with n ‐hexane for 7 days, at room temperature, protected from light.…”

“…[3–5] Among them, three (eugenials C–E) stood out for their biological activity. Eugenial C and eugenial D (Figure A, B) showed important antibacterial activity against Staphylococcus aureus and methicillin resistant S. aureus , with the minimal inhibition concentrations (MICs) lower than that of the positive control, vancomycin . The results revealed that these molecules are promising and can serve as inspiration in the development of new antimicrobial drugs.…”

1H NMR‐Guided Isolation of Formyl‐Phloroglucinol Meroterpenoids from the Leaves of Eucalyptus robusta

“…Eucalrobusone C( 3)e xhibited ap seudo molecular ion peak at m/z 453.2643[ MÀH] À ,c onsistent with the molecular formula C 28 H 38 O 5 .I ts NMR data (Supporting Information, Ta bles S1 and S3) revealed jensenone (4,6-diformyl-2-isopentanoylphloroglucinol) [9] and sesquiterpene moieties. Comparison of its NMR data with those of eugenial D [10] furtheri ndicate daeudesmane-type sesquiterpenei n3.T his deduction was also confirmedb yH MBCc orrelations, especially from H-1 to C-3/C-9/C-14, from H-4 to C-2/C-6/C-15, from H-6 to C-4/C-10/C-11, and from H-7t oC -5/C-9/C-12/C-13. The relative configurationw as determined from the ROESY spectrum,i nw hich correlations of H-7/Me-14, H-12'a/Me-14, and H-4/H-1 indicated a orientations of H-1 and H-4 and b orientationso fH -7 and Me-14.…”

“…The terpenoid moieties of FPMs usually have low degrees of oxidation and unsaturation, so determinationsoftheir absolute configuration were difficult and mostly limited to CD calculations up to now. [5,[10][11][12] Yet, the phloroglucinol moiety could theoretically allow the use of the Snatzkeh elicity rules of the CD spectrum to assign configurations ( Figure 5A-C), [13] althoughith as never been used in these particularnaturalproducts. In compounds 1 and 2,C -1 is ac hiral second sphere of ab enzene chromophore, and its absolute configuration could www.chemeurj.org be established by the Snatzke helicityr ules for the 1 L b band of the monosubstituted benzene chromophore.…”