The antioxidant activities of compounds 1–6 and controls,
BHA and vitamin E, were shown in Table 2, respectively.
Most of the isolated compounds exhibited
considerable scavenging activity on DPPH radical and
the increasing order of their activities was vitamin
E < kaempferol 3-b-D-glucopyranoside < quercetin 3-b-Dglucopyranoside
< BHA < kaempferol < quercetin < isocorilagin
< geraniin. This observation suggested that the
antioxidant activity of phenolics increased when there were
more free hydroxyl groups in the molecule, which agreed
with the previous report by Kumaran and Karunakran
(2006). Flavonoids (Quercetin 3-b-D-glucopyranoside, kaempferol
3-b-D-glucopyranoside, quercetin and kaempferol),
isolated from emblica, displayed antioxidant activities
from moderate to weak on DPPH assay and flavonoids
belonging to the quercetin class (Quercetin and quercetin
3-b-D-glucopyranoside) possessed higher antioxidant activities