Extract from wild strain of mushroom Ganoderma lucidum as natural antioxidant

Abstract

Recently, much attention has been paid to revealing natural biomaterials for clinical purposes since use of synthetic antioxidants is restricted due to their carcinogenicity. Among various natural antioxidants, polysaccharides, in general, have strong antioxidant activities and can be explored as novel potential antioxidants. The aim of this work was to examine the antioxidant properties of hot water extracted polysaccharides from Ganoderma lucidum in the form of mature fruit bodies, collected from the Bojčinska forest near Belgrade, the Republic of Serbia. Antioxidant properties were assayed in vitro, by the conjugated diene method, reducing power, scavenging abilities against 1.1-diphenyl-2-picrylhydrazyl (DPPH) radicals and chelating ability on ferrous ions. At concentrations of 1 mg/ml, the scavenging ability of G. lucidum polysaccharide extract on DPPH radicals was 74.7 %. At 1 mg/ml, the radical scavenging ability of the positive controls BHT, ascorbic acid and α-tocopherol were 11.5, 77.1 and 79.4 %, respectively. The antioxidant activity of the polysaccharide extract increased as the concentration increased to 78.0% at 20 mg/ml. Antioxidant activities of ascorbic acid and α-tocopherol were 63.8 % and 65.4% at 20 mg/ml. Polysaccharide extract from G. lucidum showed steady increase in the reducing activity as concentrations increased to 2.9 at 20 mg/ml. Ascorbic acid, used as a positive control, had a reducing power of 3.9 at 5 mg/ml. Chelating effects of the polysaccharide extract on ferrous ion increased with the increased concentrations. At 0.1-20 mg/ml, the chelating ability of G. lucidum polysaccharide extract was between 10.3-87.8%. The chelating effect of the synthetic metal chelator EDTA was 100% at 0.1-20 mg/ml, while citric acid did not prove to be good chelating agent for ferrous ions in this assay since its chelating ability was 10.3% at 20 mg/ml.

U današnje vreme sve veće pažnja se poklanja pronalaženju prirodnih bioloških materijala koji imaju antioksidativna svojstava. Neželjeni efekti, oštećenje jetre i karcinogeneza, od strane sintetičkih antioksidanata koji se koriste kao aditivi ishrani su uveliko potvrđeni. Među različitim pri rodnim antioksidantima polisaharidi privlače sve veću pažnju kao jedinjenja sa izraženom antioksidativnom aktivnošću. Cilj rada je bio da se ispitaju antioksidativna svojstva vrelog vodenog ekstrakta polisaharida gljive Ganoderma lucidum dobijenog iz zrelih plodonosnih tela, prikupljenih u Bojčinskoj šumi u blizini Beograda, Republika Srbija. Antioksidativna svojstva su ispitivana pomoću antioksidativne metode u model sistemu linoleinske kiseline, merenjem snage redukcije, sposobnosti hvatanja 1,1-difenil-2-pikrilhidrazil (DPPH) radikala i sposobnosti heliranja jona gvožđa. Pri koncentraciji od 1 mg/ml sposobnost hvatanja DPPH radikala polisaharidnog ekstrakta šumskog soja Ganoderma lucidum dostigla je nivo od 74.7%, dok su izmerene vrednosti, pri istoj koncentraciji, za pozitivne kontrole BHT, askorbinsku kiselinu i α-tokoferol iznosile 11.5, 77.1 i 79.4%. Antioksidativna aktivnost izmerena u model sistemu linoleinske kiseline zavisila je od koncentracije i povećavala se sa povećanjem koncentracije. Izmerena je vrednost od 78.0% pri koncentraciji od 20 mg/ml. Antioksidativne aktivnosti askorbinske kiseline i α-tokoferola pri koncentraciji od 20 mg/ml bile su 63.8 i 65.4%. Redukciona sposobnost polisaharidnog ekstrakta dostigla je nivo od 2.9 pri 20 mg/ml i 3.9 pri 5 mg/ml kod askorbinske kiseline koja je korišćena kao pozitivna kontrola. Sposobnost heliranja jona gvožđa se povećavala sa povećanjem koncentracije. Pri koncentraciji od 0.1-20 mg/ml izmerena sposobnost heliranja bila je između 10.3-87.8%. Helatni efekat EDTA bio je 100% u opsegu od 0.1-20 mg/ml. Limunska kiselina se nije pokazala kao dobar helirajući agens (10.3% pri 20 mg/ml).