Scutia buxifolia Reissek belongs to the Rhamnaceae family and is
popularly known as‘‘coronilha”.It is a native plant from South
America,with a dispersion area that include Rio Grande do Sul
state in Brazil,Argentina and Uruguay.Infusions of the root bark
are popularly used as a cardiotonic,antihypertensive and diuretic
(Wasicky et al.,1964).In spite of the popular use,little is known
about its secondary metabolites,with the exception of some cyclo-
peptide alkaloids isolated by Morel et al.(2005)which demon-
strated antimicrobial activities.
Preliminary phytochemical investigations of our group concern-
ing the leaves and the stem bark of S.buxifolia indicated the pres-
ence of a large number of phenolic compounds,including
flavonoids.This feature,allied to the importance of the oxidative
stress in the pathogenesis of various diseases,and the continuous
use popularly recommended as a remedy,prompted us to better
evaluate the potential antioxidant properties of this plant.At the
same time,phytochemical procedures led to the isolation and the
identification by NMR spectroscopy of four quercetin-derived
flavonols,which may play a special role in the antioxidant activi-
ties described in this study.
All chemicals were of analytical grade.Silica Gel 60,Silica Gel 60
F254 coated plates,solvents for the extractions and analytical pro-
cedures,dichloromethane,ethyl acetate,ethanol,methanol,n-
butanol,acetonitrile,ascorbic acid,and gallic acid were purchased
from Merck(Darmstadt,Germany).Folin–Ciocalteau phenol re-
agent 2 N,DPPH radical(1,1-diphenyl-2-picrylhydrazyl),rutin
and quercetin were acquired from Sigma Chemical Co.(St.Louis
MO,USA).NMR spectra were carried out on a Bruker AMX 400
spectrometer equipped with a broadband 5-mm probe,using a
spectral width of 10 ppm(parts per million).Chemical shifts were
expressed as ppm relative to the TMS.Deuterated methanol was
used as solvent for the samples.
Stem bark and leaves of S.buxifolia were collected in Dom Ped-
rito(Rio Grande do Sul State of Brazil)in October of 2007(coordi-
nates 30°5900900S and 54°2704400W).A dried voucher specimen is
preserved in the herbarium of the Department of Biology at Federal
University of Santa Maria by register number SMBD 10919.
The parts of the plant were dried at room temperature and pow-
dered in a knife mill.The powder of stem bark(651.52 g)and
leaves(372.34 g)were macerated separately at room temperature
with ethanol 70%for a week with daily shake-up.After filtration,
the two extracts were evaporated under reduced pressure to
remove the ethanol.Each extract was suspended in water and
partitioned successively with dichloromethane,ethyl acetate and
n-butanol(3 200 mL for each solvent).