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A Comprehensive View on (−)‐7‐Oxo‐ ent ‐kaur‐16‐en‐19‐oic Acid, the Major Constituent of Xylopia sericea Leaves Extract: Complete NMR Assignments, X‐Ray Crystallographic Structure, in Vitro Antimalarial Activity and Cytotoxicity
Author(s) -
Costa Gontijo Douglas,
Fernanda Alves do Nascimento Maria,
Borgati Tatiane Freitas,
Speziali Nivaldo Lúcio,
Dias de Souza Filho José,
Braga de Oliveira Alaíde
Publication year - 2019
Publication title -
chemistry and biodiversity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 70
eISSN - 1612-1880
pISSN - 1612-1872
DOI - 10.1002/cbdv.201900141
Subject(s) - heteronuclear single quantum coherence spectroscopy , two dimensional nuclear magnetic resonance spectroscopy , diterpene , chemistry , stereochemistry , dichloromethane , x ray , solvent , organic chemistry , physics , quantum mechanics
Bioguided fractionation of Xylopia sericea antiplasmodial dichloromethane leaves extract led to the isolation of (−)‐7‐oxo‐ ent ‐kaur‐16‐en‐19‐oic acid (C 20 H 28 O 3 ) that was identified by a combination of 1D and 2D NMR experiments (COSY, HMBC, HSQC, HSQC‐TOCSY, HSQC‐NOESY and NOESY) and by X‐ray crystallography. A feature to be pointed out is its (4 R ) configuration that was inferred from the NOE experiments (HSQC‐NOESY and NOESY) and X‐ray crystallography. In vitro evaluation of this rare diterpene acid against the chloroquine‐resistant strain Plasmodium falciparum W2 by the Pf LDH method showed it disclosed a low antiplasmodial activity and was not cytotoxic to HepG2 cells (CC 50 862.6±6.7 μ m ) by the MTT assay. The unequivocal NMR signals assignments, the X‐ray crystallographic structure, the assessment to the bioactivities and the occurrence this diterpene in X. sericea are reported here for the first time.