Abstract

Agaricus blazei Murrill (Agariaceae) was irradiated with gamma rays at doses of 2.5, 5, 10, 15 and 20 kGy and the antioxidant properties of its methanolic extracts were studied. At 7.5 and 10.0 mg/ml, antioxidant activities of methanolic extracts from 2.5 to 20 kGy γ-irradiated A. blazei were significantly higher than those of methanolic extract from the nonirradiated control. At 0.5–7.5 mg/ml, reducing powers of methanolic extracts from A. blazei with 2.5, 10, 15 and 20 kGy of irradiation and without irradiation were comparable. All methanolic extracts showed excellent scavenging abilities of 95.2–100.7% against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals at 0.5 mg/ml. With regard to the scavenging ability against hydroxyl radicals, unirradiated and γ-irradiated A. blazei were comparable. Total phenols were the major naturally occurring antioxidant components found in the range of 18.77–21.48 mg/g. All EC₅₀ values were below 10 mg/ml, except values in reducing power, scavenging ability against DPPH radicals and chelating ability against ferrous ions were below 1 mg/ml. That indicates the unirradiated and irradiated A. blazei were good in antioxidant properties. Summarily, up to 20 kGy of irradiation did not remarkably affect the amounts of total antioxidant components in A. blazei.

Keywords: Agaricus blazei; Methanolic extracts; γ-Irradiation; Antioxidant activity; Reducing power; Scavenging ability; Chelating ability

Article Outline

1. Introduction

2. Material and methods

2.1. Mushrooms

2.2. Antioxidant activity

2.3. Reducing power

2.4. Scavenging ability against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals

2.5. Scavenging ability against hydroxyl radicals

2.6. Chelating ability against ferrous ions

2.7. Determination of antioxidant components

2.8. Statistical analysis

3. Results and discussion

3.1. Extraction yield

3.2. Antioxidant activity

3.3. Reducing power

3.4. Scavenging ability against 1,1-diphenyl-2-picryhydrazyl radicals

3.5. Scavenging ability against hydroxyl radical

3.6. Chelating ability against ferrous ions

3.7. EC₅₀ in antioxidant properties

3.8. Antioxidant components

4. Conclusions

Acknowledgements

References