Phenolic content distribution and antioxidant activities of <i>Terminalia sericea</i> Burch

Abstract

Background: Terminalia sericea has been used traditionally for the treatment of diseases associated with oxidative stress. This study was aimed at 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.

Antioxidant Activity and Spectroscopic Characteristics of Extractable and Non-Extractable Phenolics from Terminalia sericea Burch. ex DC.

“…This study also demonstrated that the stem contained more antioxidant compounds compared to the fruit, leaves, and root. In a previous study [ 39 ], the crude extracts of T. sericea stem displayed higher antioxidant activity compared to the leaves and the root. The ester bound extractable phenolics displayed the highest average antioxidant activity compared to the free, glycoside bound extractable phenolics and non-extractable (insoluble) phenolics.…”

“…The crude extract of the root has been reported to be toxic to Monkey kidneys or Vero cells [ 36 ]. Previous studies [ 37 , 38 , 39 ] on the antioxidant activities of T. sericea have been limited to extractable antioxidants. Lupeol, inseparable mixtures of epicatechin-catechin and epigallocatechin-gallocatechin have been identified as antioxidant constituents of the acetone extract of stem bark [ 38 ].…”

In Vitro Studies on Antioxidant and Anti-Parasitic Activities of Compounds Isolated from Rauvolfia caffra Sond

“…The DPPH free radical scavenging ability of the crude extract and fractions F 1 , F 2 , F 3 , F 4 and F 5 was determined according to the spectrophotometric method of Anokwuru et al [ 29 ]. A 125 mM DPPH/methanol solution was prepared by dissolving 10 mg DPPH in 200 mL methanol.…”

“…The reducing power was determined according to the method of Anokwuru et al [ 29 ]. A 0.2 M (pH 6.6) sodium phosphate buffer (50 µL) and 50 µL of the crude extract, fractions F 1 , F 2 , F 3 , F 4 and F 5 , and compound 4 were added in triplicate in the first three wells of a 96-well plate, followed by serial dilution.…”

Phytochemical Analysis and Toxicity Evaluation of Acetone, Aqueous and Methanolic Leaf Extracts of Agapanthus praecox Willd

“…This result agreed with some reports in the literatures. Anokwuru, et al [17] reported higher yields of Acalypha wilkesiana, Azadirachta indica and Solanum scabrum in methanol extraction than in acetone. Also, Dhawan and Gupta [18] observed the highest extract yields in methanol solvent for all the plants studied.…”