Effect of wild strawberry tree (Arbutus unedo L.) leaf extract, arbutin and hydroquinone on PK-15 and HepG2 cells in vitro

Obična planika (Arbutus unedo L.) zimzelena je grmolika biljka iz porodice vrijesova, koja se zahvaljujući antimikrobnim i antioksidacijskim svojstvima svih svojih dijelova koristi kao sastojak tradicionalnih ljekovitih pripravaka. Najvaţniji biološki aktivni spojevi koje nalazimo u listu obične planike su polifenoli, od kojih je najzastupljeniji arbutin. UtvrĎen je antioksidativni učinak arbutina te njegova antikancerogena i protuupalna aktivnost. Biološki učinci arbutina dolaze od njegova metabolita hidrokinona. Ovo istraţivanje provedeno je s ciljem procjene učinka toksičnosti vodenog ektrakta listova obične planike i arbutina u dozama od 0,4 mg/mL; 0,2 mg/mL i 0,0114 mg/mL te hidrokinona u dozama od 0,28 mg/mL; 0,14 mg/mL i 0,008 mg/mL na stanice PK-15 i HepG2 u in vitro uvjetima. Test vijabilnosti stanica pokazao je da hidrokinon izaziva inhibiciju proliferacije stanica, dok vodeni ekstrakt listova obične planike i arbutina nisu pokazali negativan učinak. Pri većim koncentracijama hidrokinon oštećuje molekule DNA. Rezultati testa bojenja EtBr/AO ukazuju da stanice tretirane hidrokinonom ulaze u apaptozu i nekrozu u većoj mjeri od onih tretiranih vodenim ekstraktom listova obične planike i arbutinom. Na temelju navedenih rezultata moţemo zaključiti da ekstrakt listova obične planike i arbutin imaju niski toksični potencijal, dok hidrokinon u većim koncentracijama oštećuje stanice.Strawberry tree (Arbutus unedo L) is an evergreen wild shrub or a small tree in Ericacae family, which is widely used as an ingredient in the traditional medicine due to its antimicrobial and antioxidant properties. The most important biologically active compounds found in the leaf of the strawberry tree are polyphenols, among which the most common is arbutin. Its antioxidant, anticarcinogenic and anti-inflammatory properties have been confirmed. The effects of arbutin derive from hydroquinone, its metabolite. The aim of this study was to estimate the impact that the toxicity of the strawberry-tree leaf aqueous extract and arbutin in doses of 0,4 mg/mL; 0,2 mg/mL and 0,0114 mg/mL, and of hydroquinone in doses of 0,28 mg/mL; 0,14 mg/mL and 0,008 mg/mL, has on PK-15 and HepG2 cells under in vitro condition. Hydroquinone has induced cell proliferation inhibition, while the aqueous extract of the strawberry-tree leaf and arbutin have not shown the negative effects measured by cell viability test. Higher concentrations of hydroquinone have damaged the structure of the cells’ DNA moleculesThe results of the EtBr/AO staining test have shown that cells treated with hydroquinone entered into apoptosis and necrosis to a greater extent than those treated with the strawberry-tree leaf aqueous extract and arbutin. Based on these latter results, it can be concluded that the extract of the strawberry-tree leaf aqueous extract and arbutin have low genotoxic potential, while higher concentrations of hydroquinone damage the cells