Evaluation of antioxidant properties of different extracts of Chaetomium cupreum SS02

Abstract

To evaluate the antioxidant properties of different extracts (chloroform, ethyl acetate, n-butanol and methanol extracts) of fungus C. cupreum SS02. The antioxidant properties were evaluated by using five antioxidant methods, metal chelating assay, 2,2-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid (ABTS·), hydroxyl radical (HO·) scavenging assay, superoxide anion (O2·) radical scavenging assay, and nitric oxide (NO·) scavenging assay. Methanol extract of C. cupreum showed highest metal chelating activity (63.61 ± 0.07 mg EDTAE/g DW), followed by chloroform extract (57.25 ± 0.12 mg E DTAE/g DW) and n-butanol extract (27.33 ± 0.07 mg E DTAE/g DW) whereas ethyl acetate extract showed least metal chelating activity (18.35 ± 0.07 mg E DTAE/g DW) at 50 µg/ml. In ABTS assay, n-butanol extract showed highest ABTS inhibition activity (19.91 ± 0.14 μmol RE/g DW), followed by ethyl acetate extract (13.07 ± 0.59 μmol RE/g DW) and chloroform extract (13.07 ± 0.82 μmol RE/g DW) whereas methanol extract showed the lowest activity (11.65 ± 0.16 μmol RE/g DW at 50 µg/ml). In hydroxyl radical scavenging assay, n-butanol extract showed highest scavenging activity (31.95 ± 0.21 mg RE/g DW), followed by ethyl acetate extract (28.19 ± 0.21 mg RE/g DW), methanol extract (22.93 ± 0.37 mg RE/g DW) and chloroform extract (18.04 ± 0.21 mg RE/g DW) at 50 µg/ml. In superoxide anion scavenging assay, chloroform extract showed highest scavenging activity (56.44 ± 0.03 mg RE/g DW) followed by ethyl acetate extract (49.88 ± 0.09 mg RE/g DW), n-butanol extract (19.49 ± 0.09 mg RE/g DW) and methanol extract (7.75 ± 0.06 mg RE/g DW) at 50 µg/ml. The highest inhibition of nitric oxide radical was observed in chloroform extract of C. cupreum (11.23 ± 0.11%) followed by ethyl acetate extract (7.62 ± 0.06%), n-butanol extract (4.72 ± 0.90%) and methanol extract (3.20 ± 0.06%) at 50 µg/ml. The results showed that different extracts of C. cupreum have significant antioxidant activity due to the presence of different phytochemicals. Thus, it is suggested that C. cupreum extracts should be further studied for their antioxidant properties for food and pharmaceutical applications. Keywords: Free radicals, Hydroxide radical, Superoxide radical, Nitric oxide, Metals chelating