Inhibitory Effect of Lutein and Pycnogenol on Lipid Peroxidation in Porcine Retinal Homogenate

Abstract

Summary This study aimed to investigate the antioxidant effect of lutein, human macula pigment, and pycnogenol, which contains several flavonoids, on lipid peroxidation induced in 10% porcine retinal homogenate by the addition of 1 mM Ferric chloride (FeCl3), 50 mM 2,2'-azobis (2-amidino-propane) dihydrochloride (AAPH), or 25 mM 2,2'-azobis (2,4-dimethylvaleronitrile) (AMVN). Lipid hydroperoxide concentration was determined from the amount of thiobarbituric acid reactive substances (TBARS) in the sample following treatment. After 60 min of oxidation with FeCl3, AAPH and AMVN, the TBARS content in the retinal homogenates increased from 28.6 ± 1.6 to 85.4 ± 0.9, from 27.9 ± 1.2 to 57.2 ± 1.1, and from 26.0 ± 1.0 to 77.5 ± 2.0 nmol MDA / mg protein, respectively. Lutein did not show remarkable antioxidant activity in this experimental system. However, IC50 of pycnogenol for TBARS formation was decreased by combining 10 µM lutein in each initiator; from 12 to 5 µg/ mL in FeCl3, from 2.8 to 0.5 µg/ mL in AAPH, from 465 to 110 µg/ mL in AMVN. These results suggested that a combination treatment of lutein and pycnogenol is more effective for inhibiting lipid peroxidation in porcine retinal homogenate. This synergy might be due to efficient functional antioxidants acting in both hydrophilic and lipophilic cellular environments.

Pycnogenol® and Antioxidant Activity in Health Promotion

“…The antioxidant power of Pycnogenol Ò can provide protection in both the lipophilic and hydrophilic environments of the retina, in part by inhibiting lipid peroxidation (Spadea and Balestrazzi, 2001). Oxidative stress is a cause for several retinal diseases, so supplementation with Pycnogenol Ò and the natural xanthophyll lutein can act to prevent age-related macular degeneration (Nakanishi-Ueda et al, 2006). Pycnogenol Ò is able to directly interact with erythrocyte membranes, which increases membrane fluidity near the surface of the cell (Sivonova et al, 2004).…”

Brief Communication: French Maritime Pine Bark Extract (Pinus Pinaster ) and Its Ophthalmic Use

“…It possesses antioxidant activity and acts in synergy with Lutein for prevention of lipid oxidation in the eyes [5,6]. Anti-inflammatory activity for Pycnogenol has also been advocated [7].…”