| dc.description.abstract | Oxidative stress due to free radicals plays a fundamental role in
pathogenesis of several human diseases. Accordingly, wide search is
operative to discover novel and potent antioxidants to be used as
prophylactics and therapeutics, and also in food and cosmeceutical
industries .Thus, the aim of this study was to evaluate the antioxidant
capacity of leaves of Indigofera indica ( Family : Leguminosae) and
stems of Stereospermum suaveolens ( Family: Bignoniaceae) grown in Sri
Lanka . Oven dried (at 40°C) , powdered leaves and air dried stems were
extracted to methanol by cold extraction technique and their antioxidant
activities were evaluated in vitro using four direct antioxidant assays [1,1-
diphenyl-2-picrylhydrazyl (DPHH)], radical scavenging activity: 2,2'-
azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical
scavenging activity : ferric reducing antioxidant power (FRAP) and
oxygen radical absorbance capacity (ORAC) and two indirect antioxidant
assays [ total polyphenolic content (TPC) and total flavonoid content
(TFC)]. The results showed that both extracts exhibit moderate
antioxidant activity [ DPPH assay , leaves Vs stem : 11.53 ± 0.50 Vs
13.46 ± 0.22 mg Trolox equivalent /g ; ABTS assay , leaves Vs stem
156.66 ± 12.87 Vs 146.14 ± 3.15 mg Trolox equivalent /g , FRAP assay ,
leaves Vs stem 11.76 ± 3.93 Vs 13.59 ± 4.36 mg Trolox equivalent /g ;
ORAC assay , leaves Vs stem 198.83 ± 6.09 Vs 209.61 ± 16.10 mg
Trolox equivalents /g ; TPC assay , leaves Vs stem: 193.45 ± 9.60 Vs
102.26 ± 6.04 mg Gallic acid equivalents /g, and TFC assay , leaves Vs
stem : 22.56 ± 0.42 Vs 0.12 ± 0.04 mg Quercetin equivalents /g]. Further,
the radical scavenging activities determined by DPPH and ABTS assays
were dose dependent. These results establish, for the first time, that leaves
of I.indica and stem of S.suaveolens grown in Sri Lanka are good source
of natural antioxidants that may be effective against oxidative stress
induced pathophysiology of several diseases | en_US |
