Abstract:
Background: Cinnamomum zeylanicum Blume known as Ceylon cinnamon has been widely used
in traditional medicines since ancient times. Sri Gemunu (SG) and Sri Wijaya (SW) are the most
cultivating cinnamon varieties in Sri Lanka.
Objective: To compare in vitro antioxidant and anti-inflammatory activities of barks and leaves of
SG and SW varieties of C. zeylanicum
Methods: Aqueous extracts of SG barks (SGB), SW barks (SWB), SG leaves (SGL), and SW
leaves (SWL) were subjected to in vitro DPPH radicals scavenging assay and ferric reducing
antioxidant power (FRAP) assay using ascorbic acid (AA) as the standard. Inhibition of egg
albumin denaturation (EA) and heat-induced human red blood cell membrane stabilization
(HRBC) assays were used to assess the in vitro anti-inflammatory activity, using diclofenac
sodium as the standard. Tests were done in triplicates.
Results: Half-maximal inhibitory concentrations (IC50) of SGB, SWB, SGL, SWL and AA for
DPPH assay were 2.86±1.03, 6.58±2.63, 31.83±12.05, 26.14±12.06 and 1.78±0.37 in µg/mL,
respectively. FRAP assay showed antioxidant capacities as 90.44±10.95, 253.61±4.46,
31.22±3.94, and 65.17±4.85 in mg AA equivalent/g for SGB, SWB, SGL, and SWL, respectively.
The IC50 values obtained in EA assay for SGB, SWB, SGL, SWL and the standard were
1.78±0.10, 1.06±0.19, 2.06±0.22, 1.16±0.09, and 0.74±0.01 in mg/mL while IC50 values obtained
in HRBC assay were 1.79±0.17, 1.74±0.11, 3.44±0.15, 1.96±0.09, and 0.95±0.03 in mg/mL,
respectively. Results showed barks have significantly higher antioxidant capacity than leaves of
the same variety (p<0.05) in FRAP assay. SW variety showed the highest antioxidant capacity
among barks and among leaves of both varieties (p<0.05) in FRAP assay while comparable
activity was shown (p>0.05) in DPPH assay. When consider the anti-inflammatory potency, barks
and leaves of the same variety and barks of the two varieties showed comparable potency (p>0.05)
in EA and HRBC assays, while SWL showed the highest activity among leaves of the two
varieties (p<0.05) in HRBC assay.
Conclusion: Both barks and leaves of C. zeylanicum varieties have comparable antioxidant and
anti-inflammatory activities.
