Aim: 

No studies are reported in literature on the antioxidant capacity of the Pleurotuseryngii species-complex. The genus Pleurotus (Fr.) P. Kumm.

includes valuable edible mushrooms. These mushrooms are suitable for every type of diet thanks to their gastronomic value and low caloric, vitamins and mineral salts contents. The purpose of this study is to describe a competition Kinetics procedure for measuring the antioxidant capacity of the Pleurotuseryngii species-complex. This procedure is a spectrophometric method based on the "Crocin Bleaching Assay" (CBA).

Methods: 

The mushrooms were cleaned and then freeze-dried for futher analysis. Mushroom powders were extracted by using a Soxlet extractor. Three different solvents were used to fractionate the soluble antioxidant compounds from the mushrooms. Finally, the ethanol and ethanol/water extracts were analysed for their antioxidant capacities by the CBA.

Results: 

The CBA is a method of competition kinetics. It is more effective than the others in detecting both the antioxidant effect and the possible prooxidant action of the compound or mixture under analysis. This method is based on the crocin bleaching as a results of its oxidation determined by a source of radicals. The antioxidant capacity is calculated as the ratio (Ka/Kc) between the rate constants for the reactions of crocin with peroyl radicals in absence and in presence of antioxidant.

Conclusion: 

This protocol will allow to integrate the nutritional information on Pleurotuseryngii species-complex with the data on their antioxidant power.