Background: Terminalia sericea
has been used traditionally for the treatment of diseases associated with oxidative stress. This study was aimedat determining the distribution of phenols in the leaves, stem bark and root bark of
Terminalia sericea and their antioxidant activity.
Materials and methods: Hot and cold water, methanol/acetone extracts were evaluated for their total phenolic content (TPC), flavone/flavonol
content (FFC), flavonone/dihydroflavone content (FDFC), hydroxycinnamic acid derivative content (HCAC) and tannin content (TC). DPPH
(2,2-diphenyl-1-picrylhydrazyl) free radicals and reducing power assays were used to assess the antioxidant activity.
Results: The leaves had the highest average TPC (440) expressed in milligram Gallic Acid Equivalent (mgCAE) /gram of the extract. The
leaves also had the highest average TC (7.14) expressed in milligram Quercetin Equivalent (mgQE) /gram of the extract. The stem had the
highest average FDFC (19.23 mgQE/g) while the root had the highest average FFC (74.76 mgQE/g) and HCAC (214.57) expressed in milligram
Caffeic Acid Equivalent mgCAE/ gram of the extract. The stem exhibited the highest average DPPH free radical scavenging (9.85 μg/mL) and
reducing power (6.01 μg/mL) activities. Water was a better extracting solvent for TPC and FDFC while methanol/acetone was a better extracting
solvent for FFC and HCAC. The correlation between TC and reducing power activity (r=0.668) at
P < 0.05 suggests that tannins were
responsible for the antioxidant activity.
Conclusion: This study has shown that the distribution of phenolics differs in the organs of
T. sericea, and could affect the quality of medicinal
products sold.
