ABSTRACT
Title
Comparative antioxidant assessment of plant-derived compounds
Authors
R. Bertin
Doctorate school of Pharmacological Sciences – course in Pharmacology, Toxicology and Therapeutics.
Department of Pharmacology and Anaesthesiology - University of Padova, Largo E. Meneghetti 2, 35131 Padova, Italy.
Doctorate school of Pharmacological Sciences – course in Pharmacology, Toxicology and Therapeutics.
Department of Pharmacology and Anaesthesiology - University of Padova, Largo E. Meneghetti 2, 35131 Padova, Italy.
Abstract
Atherosclerosis is considered as the leading cause of cardiovascular diseases in the developed world; biological studies have provided various evidences that free radical induced oxidation of low density lipoproteins (ox-LDLs) critically contributes to the risk of atherogenesis. Production and metabolism of radicals normally are well regulated processes in tissues, but their deregulation can lead to the development of oxidative stress-related disorders and inflammatory-like tissue damages; therefore, inhibition of LDL peroxidation by antioxidants supplementation becomes an attractive strategy to prevent and possibly to treat atherosclerosis and related cardiovascular diseases in human [1].
The aim of this study is to identify several natural compounds endowed with antioxidative properties in order to prevent ox-LDLs generation.
Baicalein (from Scutellaria baicalensis G.), (-)-bilobalide (Ginkgo biloba L.), eupatorin (Eupatorium semiserratum DC.), Galangin (propolis), magnolol (Magnolia officinalis L.), myricetin (Myrica nagi T.), oleuropein (Olea europaea L.) and silybin (Silybum marianum L.) are constituents of widely used traditional medicine; we will test them with a preliminary antioxidant assay using DPPH, an extensively used protocol to evaluate antioxidant activity of plant samples. This method is based on the scavenging of 1,1-diphenyl-2-picrylhydrazyl, a stable organic nitrogen radical which upon a reductive reaction modifies its deep-purple original colour in a bright yellow-coloured solution. The assay measures the reducing ability of antioxidants towards the DPPH radical using a spectrophotometric analysis [2].
Beside this evaluation, we further study a specific cell model to investigate ROS production using human umbilical vein endothelial cell (HUVEC) primary cultures. HUVEC cells represent an interesting model which plays a pivotal role in the study of different patophysiological processes, including arterial disease. The protective function of antioxidants towards oxidative stress will be assessed using the dichlorofluorescein assay, a fluorimetric probe used to evaluate intracellular hydrogen peroxide generation by flow cytometry. The theory behind this method is that 2’,7’-dichlorofluorescein diacetate (DCFH-DA) may cross cell membranes and is hydrolyzed enzymatically by intracellular esterases to nonfluorescent DCFH; in the presence of reactive oxygen species DCFH is oxidized to highly fluorescent dichlorofluorescein (DCF). Cellular antioxidant capacity may be correlated to the fluorescence intensity of the probe [3].
Our research suggests also a further characterization of natural constituents directly towards human LDL oxidation.
The results encourage the future search of plant-derived compounds as effective antioxidant agents, in order to decrease ox-LDLs production and to provide a suitable basis for novel pharmaceutical developments against free radicals damage.
1) Hou L et al. (2004) – Chem Phys Lipids 129: 209-219.
2) Ashwell RN et al. (2010) – Molecules 15: 6905-6930.
3) Wang H et al. (1999) – Free rad Biol Med 27: 612-616.
The aim of this study is to identify several natural compounds endowed with antioxidative properties in order to prevent ox-LDLs generation.
Baicalein (from Scutellaria baicalensis G.), (-)-bilobalide (Ginkgo biloba L.), eupatorin (Eupatorium semiserratum DC.), Galangin (propolis), magnolol (Magnolia officinalis L.), myricetin (Myrica nagi T.), oleuropein (Olea europaea L.) and silybin (Silybum marianum L.) are constituents of widely used traditional medicine; we will test them with a preliminary antioxidant assay using DPPH, an extensively used protocol to evaluate antioxidant activity of plant samples. This method is based on the scavenging of 1,1-diphenyl-2-picrylhydrazyl, a stable organic nitrogen radical which upon a reductive reaction modifies its deep-purple original colour in a bright yellow-coloured solution. The assay measures the reducing ability of antioxidants towards the DPPH radical using a spectrophotometric analysis [2].
Beside this evaluation, we further study a specific cell model to investigate ROS production using human umbilical vein endothelial cell (HUVEC) primary cultures. HUVEC cells represent an interesting model which plays a pivotal role in the study of different patophysiological processes, including arterial disease. The protective function of antioxidants towards oxidative stress will be assessed using the dichlorofluorescein assay, a fluorimetric probe used to evaluate intracellular hydrogen peroxide generation by flow cytometry. The theory behind this method is that 2’,7’-dichlorofluorescein diacetate (DCFH-DA) may cross cell membranes and is hydrolyzed enzymatically by intracellular esterases to nonfluorescent DCFH; in the presence of reactive oxygen species DCFH is oxidized to highly fluorescent dichlorofluorescein (DCF). Cellular antioxidant capacity may be correlated to the fluorescence intensity of the probe [3].
Our research suggests also a further characterization of natural constituents directly towards human LDL oxidation.
The results encourage the future search of plant-derived compounds as effective antioxidant agents, in order to decrease ox-LDLs production and to provide a suitable basis for novel pharmaceutical developments against free radicals damage.
1) Hou L et al. (2004) – Chem Phys Lipids 129: 209-219.
2) Ashwell RN et al. (2010) – Molecules 15: 6905-6930.
3) Wang H et al. (1999) – Free rad Biol Med 27: 612-616.