Total Phenolic Contents and Antioxidant Activity of Nine Medicinal Plants used in Nigerian Traditional Medicine
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Date
2018-09-15
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Publisher
Tropical Journal of Natural Product Research
Abstract
In Nigerian ethnobotany, several medicinal plants have been used for decades for the management of various ailments. Although several ethnobotanical studies have been conducted to document the most frequently used medicinal plants in the treatment of oxidative stress associated diseases, there is need to validate the therapeutic potentials of these plants. Therefore, this study was conducted to determine the radical scavenging ability as well as the total phenolic contents of nine medicinal plants used in Nigerian ethnobotany for the treatment of inflammation, diabetes and related medical conditions.
The methanol extracts of nine medicinal plants selected from Southwestern Nigeria ethnomedicinal plants were evaluated for their antioxidant activity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging assay and their total phenolic content was determined using Folin-Ciocalteu reagent. All the extracts tested showed significant DPPH scavenging activity. Amongst the nine plants, Bridelia ferruginea, Piper guineense and Nauclea diderrichii had the highest antioxidant activity with IC50 of 11.46, 15.02 and 18.12 μg/mL, respectively, compared with the standard drugs; ascorbic acid (IC50 = 1.40 μg/mL) and gallic acid (IC50 = 0.79 μg/mL). The results of total phenolic content showed N. diderrichii with the highest phenolic content of 347.77 mg gallic acid equivalent per gramme of extract (GAE/g extract), while Holarrhena floribunda G.Don. (Apocynaceae) had the least phenolic content of 12.58 mg GAE/g extract. The result obtained from this study revealed that some of the plant extract exhibited free radical scavenging ability and could serve as candidates in the search for natural antioxidants.