Comparative assessment of antioxidant and membrane-protective properties of medicinal plant extracts

Abstract

Medicinal plants are a valuable raw material for obtaining phytodrugs with a wide range of pharmacological and therapeutic effects, which are acting fast, do not possess cumulative properties and are less accompanied by undesirable side effects. Modern assessment of the species diversity of the medicinal flora and its resource potential is especially important in designing an effective system that fights diseases caused by oxidative stress. Thus, the purpose of scientific research is to study and establish a list of medicinal plant extracts with strongest antioxidant and membrane-protective effect on liver cells exposed to oxidative stress. Determination of medicinal plant extracts that exhibit highest antioxidant and membrane-protective activities will allow us to use it in creating of an effective phytocomposition that would inhibit the action of lipid peroxidation (LPO) and osmotic stress, which lead to excessive damage of cell constituents and development of oxidative stress. For this purpose, LPO levels were detected by measuring malondialdehyde concentration in the liver microsomes whereas the osmotic hemolysis was measured in a hypotonic solution of 0.4% NaCl followed by optical density measurement at 540 nm. It was established that LPO levels in liver microsomes as well as osmotic fragility of erythrocyte membranes are plant extract dose-dependent. As a result, 3 out of 9 plant extracts have significant membrane-protective properties. Plants belong to the families: Urtica dioica, Viola tricolor, Vacciniumvitis. In addition, Valeriana officinalis (leaves), Viola tricolor, Limonium gmelini, Vaccinium vitis, Hypericumper foratum and Capsella bursa-pastoris showed the strongest antioxidant property. All plant extracts contained such biologically active compounds as polyphenols and flavonoids. Our results suggest further study of the antioxidant and membrane-protective effects of medicinal plant extracts tested here may guide phytotherapy to development of new dosage forms, and advance the development of unconventional therapeutic and preventive approaches against oxidative stress related diseases.