Abstract
BackgroundIn humans, many diseases are associated with the accumulation of free radicals. Antioxidants can scavenge free radicals and minimize their impact. Therefore, the search for naturally occurring antioxidants of plant origin is imperative. Here, we aimed to investigate the antioxidant and free radical scavenging properties of methanolic extracts from Tabebuia pallida (T. pallida) stem bark (TPSB), root bark (TPRB), leaves (TPL), and flowers (TPF).MethodsThe antioxidant and free radical scavenging activity were determined by several standard methods using spectrophotomer. Total phenolic and flavonoid contents were estimated using Folin-Ciocalteu reagent and aluminum chloride colorimetric assay methods, respectively.ResultsAmong the extracts, TPL showed the highest total antioxidant capacity followed by TPRB, TPF, and TPSB. Based on DPPH and hydroxyl radical scavenging activity, TPL showed strong scavenging activity (91.05 ± 1.10 and 62.00 ± 0.57) with IC50 of 9.20 ± 0.28 and 46.00 ± 2.84 μg/mL, respectively when compared with standard BHT (IC50 of 7.00 ± 0.25 μg/mL) and CA (75.00 ± 0.14 μg/mL). These results suggest that TPL had the highest radical scavenging activity among the extractives that closely resembled the standard’s. In lipid peroxidation inhibition assay, TPL exhibited the most potent inhibitory activity (83.18 ± 2.12 %) with IC50 of 12.00 ± 2.12 μg/mL, which closely resembled standard CA (IC50 of 10.50 ± 0.28 μg/mL). Also, the reducing capacity on ferrous ion was in the following order: TPL > TPRB > TF > TPSB. The phenolic and flavonoid contents of TPL were higher than other extractives. A positive correlation (pvalue <0.001) was observed between phenolic content and free radical (DPPH· and ·OH) scavenging efficiencies and lipid peroxidation inhibition activity.ConclusionMethanolic extract of T. pallida leaf is a potential source of natural antioxidants and serves as an effective free radical scavenger and/or inhibitor. Hence, T. pallida might be a good plant-based pharmaceutical product for several diseases caused by free radicals.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-015-1618-6) contains supplementary material, which is available to authorized users.
Highlights
In humans, many diseases are associated with the accumulation of free radicals
T. pallida might be a good plant-based pharmaceutical product for several diseases caused by free radicals
At the concentration of 100 μg/mL, the absorbance of methanolic extracts of Tabebuia pallida leaves (TPL), Tabebuia pallida root bark (TPRB), TPSB, Tabebuia pallida flower (TPF) and CA was in the range of 0.525 ± 0.032–1.78 ± 0.083; while at 150 μg/mL, the absorbance of methanolic extracts of TPL, TPRB, TPSB, TPF and CA was in the range of 0.648 ± 0.030-2.267 ± 0.041
Summary
Many diseases are associated with the accumulation of free radicals. Antioxidants can scavenge free radicals and minimize their impact. There is strong evidence that many dangerous pathophysiological processes, such as cancer, diabetes and cardiovascular and neurodegenerative diseases, are associated with the accumulation of free radicals [1,2,3]. Consumption of antioxidantenriched fruits and vegetables is known to lower the risk of several diseases caused by free radicals [4]. Such health benefits are mainly due to the presence of phytochemicals such as polyphenols, carotenoids, and vitamin E and C [5]. The assessment of such properties remains an interesting and useful task, to find promising sources of natural antioxidants for functional foods and/or nutraceuticals [7, 8]
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