Antioxidant activity and phenolic content of aqueous and ethanolic extracts from the leaves of Campomanesia velutina (Cambess.) O. Berg

Marcela Michel Araújo, Fernanda Cristina Ferrari, Dênia Antunes Saúde Guimarães
Laboratório de Plantas Medicinais, Escola de Farmácia, Universidade Federal de Ouro Preto
Campus Morro do Cruzeiro, s/n. Ouro Preto, Minas Gerais, CEP 35400-000, Brazil
[email protected]
Campomanesia velutina leaves and branches infusions are used in Brazilian folk medicine to treat diarrhea and to ameliorate intestinal cramps, respectively. Previous studies demonstrated the ability of C. velutina leaves extracts to reduce hyperuricemia through inhibition of xanthine oxidase and inflammatory response triggered by MSU crystals1. Ethanolic extract from the leaves also showed antiedematogenic and antinociceptive activities2. Since oxidative stress is implicated in the physiopathology of inflammation and gout, the aim of this study was to investigate the role of C. velutina extracts on oxidative process and thus achieve a better understanding of the mechanisms underlying the observed biological effects. For this, aqueous and ethanolic extracts from the leaves were assayed on DPPH• (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay3, discoloration of ABTS•+ radical (2,2'-azino-bis[3ethylbenzthiazoline-6-sulfonic acid])4 and β-carotene/linoleic acid bleaching assay5. Quercetin was used as a reference standard. Additionally, phenolic content was also evaluated by Folin-Ciocalteu method6. The results are shown on Table 1.

Table 1 – Antioxidant effects and phenolic contents of aqueous and ethanolic extracts from the leaves of Campomanesia velutina
Sample DPPH• ABTS•+ β-carotene/linoleic acid Phenolic content
CE50 µg/mL TEAC value CE50 µg/mL mg of galic acid/g of extract
AEL 36,50 1,78 ± 0,021 99,17 189.65 ± 0.165
(34,53-38,71) (81,76 – 114,4)
EEL 30,34 2,16 ± 0,089 65,62 224.76 ± 0.165
(28,36-32,53) (∞)
Quercetin 8,39 10,14 ± 0,324 0,49 -
(∞) (∞)
AEL = aqueous extract of leaves; EEL = ethanolic extract of leaves

Both extracts showed antioxidant activity at the three evaluated methods, demonstrating that they have in their composition substances capable of donating electrons or a hydrogen atom and substances with the ability to inhibit the formation of free radicals during peroxidation of a lipid. Among secondary metabolites able to act in both ways, flavonoids stand out. They are the most common metabolites among phenolic compounds and widely recognized for their antioxidant capacity. In fact, EEL was the most effective in all assays and also has the biggest phenolic content. Thus, it is reasonable to assume that the antioxidant activity observed for the aqueous and ethanolic extracts of C. velutina leaves is related to the presence of phenolic compounds. The demonstration of extracts antioxidant activity indicates that they would be capable of acting on oxidative stress.

References: 1 Araújo, MCPM; et al. Revista Brasileira de Farmacognosia, v.26, p.720-727, 2016; 2 Michel, MCP; et al. Revista Brasileira de Farmacognosia, v.23, p. 927-936, 2013; 3 Brand-Willians; et al. Lebensmittel-Wissenschaft & Technologie, v.28, p.25-30, 1995; 4 Re, R; et al. Free Radical Biology & Medicine, v.26, p.1231-1237, 1999; 5 Miller, HE. Journal of American Oil Society, v.48, p.91, 1971; 6 Swain, T; Hillis, WE. Journal of the Science of Food and Agriculture, v.10, n.1, p.63-68, 1959.

This work was suportted by FAPEMIG-CDS-APQ-01426-11, Rede TOXIFAR/FAPEMIG, CNPq, CAPES and Universidade Federal de Ouro Preto.