Olive leaf extract modulates cold restraint stress-induced oxidative changes in rat liver

Abstract

Recently, the beneficial effects of different single doses of standardized dry olive (Olea europaea L.) leaf extract (OLE) in cold restraint stress (CRS)-induced gastric lesions in rats and its influence on oxidative parameters in gastric mucosa were demonstrated. The present study was undertaken to investigate the long-term pretreatment efficacy of OLE and its potential in the modulation of CRS- induced oxidative changes at the liver level. The experimental animals were divided into four groups, i.e., control, OLE-treated, CRS non-treated and CRS treated with OLE (CRS+OLE) groups. CRS caused severe gastric lesions in all non-pretreated animals and two-week pretreatment with OLE (80 mg per kg of body weight) attenuated stress-induced gastric lesions significantly. The malondialdehyde (MDA) level as an index of lipid peroxidation, superoxide dismutase (SOD) and catalase (CAT) activities were measured spectrophotometrically in liver tissue homogenates. The MDA level was increased in the CRS group and significantly decreased in the CRS+OLE group. The SOD and CAT activities were significantly decreased in the CRS group. In the CRS+OLE group, the activities of these two enzymes were significantly increased in comparison with the CRS group. The results obtained indicate that long-term supplementation with OLE provides oxidant/antioxidant balance in liver during stress condition.

Nedavno su pokazani povoljni efekti različitih pojedinačnih doza standardizovanog ekstrakta lista masline (Olea europaea L.) na želudačne lezije pacova indukovane imobilizacionim stresom ubrzanim hladnoćom (CRS) i njegov uticaj na parametre oksidativnog stresa u želudačnoj sluznici. U ovoj studiji ispitivan je efekat dugotrajnog pretretmana listom masline i njegov potencijal u modulaciji CRS-om indukovanih oksidativnih promena na nivou jetre. Eksperimentalne životinje su podeljene u četiri grupe: kontrolna, tretirana ekstraktom lista masline (OLE), CRS i grupa kod koje je CRS tretiran ekstraktom (CRS+OLE). CRS je prouzrokovao ozbiljna oštećenja želuca kod svih nepretretiranih životinja, a dvonedeljni pretretman sa OLE (80 mg kg-1 t.t.) značajno je smanjio stresom indukovane želudačne lezije. Malondialdehid (MDA), kao pokazatelj lipidne peroksidacije, aktivnosti superoksid-dismutaze (SOD) i katalaze (CAT) mereni su spektrofotometrijski u homogenatima tkiva jetre. Nivo MDA se značajno povećao u CRS grupi, a potom značajno smanjio u CRS+OLE grupi. Aktivnosti SOD i CAT bile su značajno smanjene u CRS grupi, dok je u CRS+OLE grupi životinja aktivnost ova dva enzima znatno povećana u poređenju sa CRS grupom. Dobijeni rezultati ukazuju na to da dugotrajno prehranjivanje ekstraktom lista masline pomaže uspostavljanje oksidativne-antioksidativne ravnoteže u jetri tokom stresa.