Evaluation of the Free Radical Scavenging Activities of Ellagic Acid and Ellagic Acid Peracetate by EPR Spectrometry

The purpose of this study was to examine the free radical scavenging and antioxidant activities of ellagic acid (EA) and ellagic acid peracetate (EAPA) by measuring their reactions with the radicals, 2,2-diphenyl-1-picrylhydrazyl and galvinoxyl using EPR spectroscopy. We have also evaluated the influence of EA and EAPA on the ROS production in L-6 myoblasts and rat liver microsomal lipid peroxidation catalyzed by NADPH. The results obtained clearly indicated that EA has tremendous ability to scavenge free radicals, even at concentration of 1 µM. Interestingly even in the absence of esterase, EAPA, the acetylated product of EA, was also found to be a good scavenger but at a relatively slower rate. Kinetic studies revealed that both EA and EAPA have ability to scavenge free radicals at the concentrations of 1 µM over extended periods of time. In cellular systems, EA and EAPA were found to have similar potentials for the inhibition of ROS production in L-6 myoblasts and NADPH-dependent catalyzed microsomal lipid peroxidation.

Kinetic Behaviour of Skin Pigmentation Inhibitory Activity of some Selected Nigerian Medicinal Plants and Other Related Antioxidant Properties

Background: Over exposure to Ultra Violet (UV) radiation is one of the most significant external stress-inducing factors resulting into occurrence of skin pigmentation among others in human body. The biological implication of such disorders is not only limited to premature skin aging and cancer, but also resulted into economic loss of perishable agricultural products. Methods: Methanol extracts of ten (10) medicinal plants with skin health traditional history were selected for this study. The biological profile of the extracts was assessed in an in-vitro system using colorimetric assays: tyrosinase inhibition, Ferric-ion Reducing Antioxidant Power (FRAP), Trolox Equivalent Absorbance Capacity (TEAC) and Fe II-induced microsomal lipid peroxidation. Results: Representative of asteraceae such as Laggera pterodonta (S3); Ageratum conyzoides (S4) and Chromolaena odorata (S5), while Euphorbia convoluloides (S8) were found to possess good anti- tyrosinase activity (IC50 = 177.50; 125.08; 167.58; 161.92) μg/ml respectively, in which the rate of formation of dopachrome proceeded via pseudo second order kinetic using the Largergren model. Other notable inhibition of oxidative stress displayed by the methanol extracts includes S7 (FRAP = 1905.12 ± 2.85 µM AAE/g); S1 & S6 (TEAC = 2163.48 ± 2.80; 1044.35 ± 28.99) µM TE/g, while S7 & S9 showed highest inhibitory activities on Fe II-induced microsomal lipid peroxidation (IC50 = 33.625; 35.125) µg/ml, respectively in competitive manner to that of the commercial anti-oxidant EGCG (IC50 = 36.250 µg/ml). Conclusion: The outcome of the biological properties of the selected plant extracts in this study suggested the existence of relationship between the traditional claims and the scientific data therein.

A comparative study of phenolic compound antioxidant activity by the polarography method, using microsomal lipid peroxidation in vitro

For comparative purposes, a quantitative estimation of antioxidant activity of phenolic compounds of different classes was conducted by way of the polarography method, via the ADP-Fe2+ model of the induced ascorbate-dependent lipid peroxidation of rat liver micro-somes within an in-vitro system. As a result, it was recognized that the antioxidant properties of phenolic compounds depend on the nature and chemical structure of several substances. In respect of such activity, leaders in the classes of investigated polyphenolic compounds are: Propyl gallate = Gallotannin (Phenolcarboxylic acids and their derivatives) > Quercetin = Myricetin (Flavonols) > Luteolin (Flavo n) = Mangiferin (Xanthones) > Kaempferol (Flavonols) = Catechin (Flavans). Thus, the assessment of the inhibition ability of the lipid peroxidation of microsomes by phenolic compounds can be used as an accessible test for the preliminary quantitative estimation of their antioxidant properties.

Effects of hypericin on the oxidative stress and modulation of cytochrome P450 (CYP1A) activity in microsomes

Hypericin is a pigment present in the widely distributed medicinal plant Hypericum perforatum L. (Hypericaceae). In our research, hypericin was found to be an inhibitor of NADPH/Fe2+ induced microsomal lipid peroxidation and NADPH-dependent lucigenin chemiluminescence emission in vitro. Hypericin also inhibited the microsomal CYP1Adependent 7-ethoxyresorufin O-deethylase (EROD) which participates in the metabolic activation of xenobiotics including chemical carcinogens.

Purification of Pomegranate Pericarps (Punica granatum l.) Extracts with Macroporous Resins and Evaluation of Antioxidant Activities In Vivo

Punica granatum L. Pomegranate has been traditionally used as a folk fruits for centuries in Oriental countries. It extract and subsequent fractions were used to evaluate antioxidant and related activities of Punica granatum L. It were extracted by 70% acetone, and then purified by HPD-400 macroporous adsorbent resins column. The aim of this study was to verify the antioxidant properties of acetone extracts of pomegranate pericarps and their lyophilized samples, and also to study the relationship between the activity and the contents of the tannins. The effects of natural extracts on microsomal lipid of mice liver and erythrocyte membrane lipid were examined. Vc/Fe2+, Cys/Fe2+induced microsomal lipid peroxidation, UV light induced erythrocyte membrane lipid peroxidation were measured by malondialdehyde (MDA) content with spectrophotometric methods. The natural plant extracts not only diminish the Vc/Fe2+,Cys/Fe2+ induced microsomal lipid peroxidation, UV light induced erythrocyte membrane lipid peroxidation and also showed its activity in a concentration-dependent manner. Our study found that the higher tannins contents showed more effective of antioxidant properties. Keywords: Punica granatum L.; liver microsome; antioxidant activity; Lipid peroxidation

Butylated hydroxyanisole alleviates ferric nitrilotriacetate induced nephrotoxicity in rats by abrogation of oxidative stress

In this study the effect of butylated hydroxyanisole (BHA), a phenolic antioxidantused in food on Ferric‐Nitrilotriacetate (Fe–NTA) induced nephrotoxicity is reported. Fe‐NTA (9 mg Fe/kg body weight, intraperitoneally) treatment enhanced the renal microsomal lipid peroxidation and hydrogen peroxide generation to ~2‐2.5 folds compared to saline‐treated control and glutathione levels and the activities of antioxidant enzymes decreased to a range of 2–2.5 fold in kidney. These changes were reversed significantly in animals receiving a pretreatment of BHA. Pretreatment with BHA prior to Fe‐ NTA treatment reduced microsomal lipid peroxidation and hydrogen peroxide generation to 1.3‐1.5 fold compared to control group and glutathione and the activities of antioxidant enzymes increased to a range of 1.5‐2 folds in kidney. Fe‐NTA administration enhanced value of blood urea nitrogen and creatinine to 3.7 and 2.5 fold respectively as compared to their corresponding control group. Administration of Fe‐NTA to rats receiving a pretreatment of BHA led to a significant diminution in both of these values. The results indicate that BHA is a potent chemopreventive agent and suppresses Fe‐NTA induced nephrotoxicity in rats.