ANTI-RADIATION AND ANTI-RADICAL ACTIVITY OF HYDROPONICALLY PRODUCED HOP EXTRACT

Abstract

Plants cultivated by hydroponic techniques allow the production of high quality and ecologically sound raw materials, without any harm to the environmental biodiversity. Hydroponically grown hop (Humulus lupulus L., 'Chinook') was used to test the anti-radiation and anti-radical activity of its extracts in vitro and in vivo. Free radical scavenging capacity of the hop methanol extract was determined using the stable radical 1.1-diphenyl-2-picrylhydrazyl (DPPH * ) discoloration method. The ability of hop aqueous extracts to prevent radiation induced H 2 O 2 -enhanced erythrocyte oxidative damage was examined in a suspension with isolated rat erythrocytes. In white rats, aqueous hop extract was orally administered for 3 consecutive days and then they were exposed to X-ray irradiation at LD 50/30 (4.0 Gy) and LD 100/30 (7.6 Gy). The radioprotective activity of aqueous hop extracts was evaluated. A dose-dependent activity of the hop extract was revealed in the DPPH * neutralization test. Aqueous hop infusions manifested an explicit membrane-stabilizing activity, which protected membranes from the damaging effects of stress-factors and prevented the increase of erythrocyte hemolysis levels in the suspension medium. The survival index of animals given aqueous hop extract following X-ray irradiation at 4.0 Gy was up to 30% higher compared to untreated animals. However, no anti-radiation effect was observed at lethal dose level of radiation of 7.6 Gy. Overall, the results suggest a high antioxidant and radioprotective activity of hop extracts. Furthermore, phyto-preparations containing hop can increase animal resistance to radiation at doses below LD 100/30 .