Salacia campestris root bark extract: peroxidase inhibition, antioxidant and antiradical profile

José Carlos Rebuglio Vellosa,Iguatemy Lourenço Brunetti,Maysa Furlan,Najeh Maissar Khalil,Vânia Aparecida De Freitas Formenton Macedo Dos Santos Santos,Olga Maria Mascarenhas De Faria Oliveira,Vânia Ortega Gutierres

doi:10.1590/s1984-82502009000100012

Abstract

Reactive oxygen species (ROS) and free radical species have been implicated in initiating or accompanying many diseases in living organisms; there is thus, a continual need for antioxidants molecules to inactivate ROS/free radicals. Many studies of plants crude extracts have demonstrated free-radical scavenging and antioxidant action. Salacia species have long been used, in several countries, as traditional medicines against certain diseases and for their anti-inflammatory properties. In this study, Salacia campestris Walp (Hippocrateaceae) root bark ethanol extract (ScEtOH) was assessed for its ability to scavenge free radicals and reactive oxygen species; the results were expressed as percentage inhibition of the active species. ScEtOH was efficient against studied species: DPPH radical (obtained inhibition = 30%), ABTS•+ (IC50 = 1.8±0.8 μg/mL), HOCl (IC50 = 1.7 ± 0.1 μg/mL), O2•- (obtained inhibition = 32%), and NO• (obtained inhibition = 18 %). Peroxidase activity inhibition was evaluated through the guaiacol oxidation reaction catalyzed by hemin, HRP and myeloperoxidase (MPO); data showed that ScEtOH at 10 μg/mL led to 54 and 51% of inhibition, respectively, for the hemin and HRP systems. In the MPO system, ScEtOH promoted a 50% inhibition at 8.9 μg/mL, whereas quercetin, a powerful MPO inhibitor, inhibited this system at 1.35 μg/mL.

Highlights

The oxidative burst from polymorphonuclear neutrophils (PMN) entail the production of reactive oxygen species (ROS) generated by two key enzymes, NADPH oxidase and myeloperoxidase (MPO)
This study was undertaken in order to assess the antioxidant activity of crude ethanol extract of S. campestris root bark (ScEtOH) by determining its capacity to scavenge free radicals and some reactive oxygen species, and inhibit peroxidase activity from hemin, HRP type VI and MPO
We evaluated the effect of S. campestris extract (10, 1 and 0.1 μg/mL) on: i) Hemin, prosthetic group of peroxidases; the assay was performed in sodium phosphate buffered saline (PBS) pH 7.0, 250C, using 3 mM hemin, 2.5 mM H2O2, and 5 mM guaiacol; ii) HRP, an important and well studied peroxidase used as a model for peroxidase inhibition studies; we used Dulbecco’s phosphate buffered saline (PBS-D), at 37 0C, 7 nM HRP, 2 mM guaiacol and 0.1 mM H2O2 which initiated the reaction, followed for 1 min at 470 nm

Summary

INTRODUCTION

The oxidative burst from polymorphonuclear neutrophils (PMN) entail the production of reactive oxygen species (ROS) generated by two key enzymes, NADPH oxidase and myeloperoxidase (MPO). Experimental data have indicated that free radicals play a critical role in a variety of pathological processes, including aging, multiple sclerosis, inflammation, coronary heart and cardiovascular diseases, senile dementia, arthritis and atherosclerosis (Ferreira, Matsubara, 1997; Babior, 2000; Benedì et al, 2004; Vellosa et al, 2007a). Recent studies shown that a number of plant products, including polyphenols, flavonoids and terpenes and various plant extracts, exert a free-radical scavenging and an antioxidant action (Corsino et al, 2000; Pereira et al, 2005; Carvalho et al, 2005; Cui et al, 2005; Benedì et al, 2004;). Quinonemethide triterpenes, secondary metabolites restricted to the higher plant families Celastraceae and Hippocrateaceae, have shown a variety of biological activity such as antitumoral, antimicrobial and antimalarial (Corsino et al, 2000). It would be useful to know if crude extract or isolated compounds from S. campestris are able to inhibit ROS generation by peroxidases, mainly MPO

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSION