Comparative Antioxidant Activities of Extracts of Vernonia amygdalina and Ocimum gratissimum Leaves

Abstract

Vernonia amygdalina and Ocimum gratissimum occupy prominent positions in the diets of several Nigerian ethnic groups. This study therefore compared the phenolic content and some antioxidative activities of the ethanolic leaf extracts of these two plants. Ethanolic extracts of freshly plucked leaves were obtained using standard procedures. The phenolic content and antioxidant capacity of the vegetables were quantified in vitro. The results show that O. gratissimum contains higher amounts of total phenolics (168.5 ± 5.50 and 97.0 ± 0.01 mg gallic acid equivalents/g extract respectively) and flavonoids (126.7 ± 1.00 and 65.4 ± 4.42 mg quercetin equivalents/g extract respectively) than V. amygdalina. A dose-dependent increase in flavonol content was observed for both extracts with higher contents obtained in the O. gratissimum extract. O. gratissimum also has higher DPPH radical scavenging activity (IC 50 values of 105.7 and 111.8 µg/ml respectively) and ferric reducing antioxidant potential (FRAP) (110.0 ± 0.02 and 85.0 ± 0.01 mg Fe 2+ /g extract). O. gratissimum also had higher reducing power than V. amygdalina at the concentrations studied. Standard ascorbic acid however had higher antioxidant activity values for the DPPH, FRAP and reducing power assays. Both plant extracts reasonably inhibit lipid peroxidation at 31.4 ± 0.15% for V. amygdalina and 42.8 ± 1.00% for O. gratissimum. The results further substantiate the medicinal value of these vegetables. Consumption of these vegetables is encouraged to help militate against deleterious effects of reactive species.

In vivo evaluation of graded fresh leave extracts of vernoniaamygdalina and ocimumgratissimum on some oxidative stress indicators in rats

“…A et al, 2012). Total phenol values obtainedfrom this study for VA and OG are higherthan that earlier reported (Oriakhi et al, 2013). The reason for this observed disparity in total phenol contents may be attributed either to the nature of the young leaves, bioavailability of soil nutrients or plant species or combina- Graded fresh leave extracts of vernoniaamygdalina and ocimumgratissimum tion of one or more of these.…”

“…A et al, 2012) had reported presence of alkaloid and quantitative values of phytochemicals for OG. Other authors on similar study Oriakhi et al, (2013), had shown higher phenolic content values for both VA and OG (Oriakhi et al, 2013).…”

“…A recent study on the comparative antioxidant activities of extracts of Vernoniaamygdalina and Ocimumgratissimum leaves had substantiated the medicinal value of these vegetables and encouraged their consumption to help militate against deleterious effects of reactive species (Oriakhi et al, 2013). It was observed that the report (Oriakhi et al, 2013) was silent on the nature of the leaves used as these plants are noted to be shrubs.…”

“…It was observed that the report (Oriakhi et al, 2013) was silent on the nature of the leaves used as these plants are noted to be shrubs. Whether the fresh young leaves of these plants will show the same effect on oxidative stress is not clear.…”

The 15-lipoxygenase inhibitory, antioxidant, antimycobacterial activity and cytotoxicity of fourteen ethnomedicinally used African spices and culinary herbs

“…(Lin et al, 2001;Olaleye, 2007) Leaves Antibacterial , α-glucosidase and α-amylase inhibitory, antidiabetic Salehi et al, 2013;Saxena et al, 2011). (Bruneton, 1999) Roots Antibacterial, spermatotoxicity, cytotoxicity, genotoxicity, insecticidal, antioxidant, (Akinboro and Bakare, 2013;Djeussi et al, 2013;Koubala et al, 2013;Oriakhi et al, 2014 (Bopitiya and Madhujith, 2013;Seukep et al, 2013;Sharif et al, 2013). Bankole et al, 2007).…”