Effect of Extraction Processes on Bioactive Compounds from Pleurotus ostreatus and Pleurotus djamor: Their Applications in the Synthesis of Silver Nanoparticles

The objective of this study was to obtain bioactive compounds from extracts of Pleurotus ostreatus and Pleurotus djamor to be used as reducing agents in the synthesis of silver nanoparticles (AgNPs). The mushrooms were dried using two methodologies: solar dehydration and cabinet oven dryer. Two procedures were applied to extract bioactive compounds from the fresh and dehydrated Pleurotus spp. In the first, maceration was applied at 25 degrees C using water and ethanol at different concentrations with stirring for 48 h. In the second, extractions were carried out by boiling for 2 h using Soxhlet equipment. Total phenolic compounds, flavonoids and anthocyanins, and ascorbic acid were determined. Antioxidant capacities were quantified by ABTS and DPPH methods. For both species, the extract obtained by maceration with 100% water, and dried in the solar dehydrator exhibited the highest antioxidant activities. The extracts were used in the synthetic reactions of AgNPs, using a suspension of 3 mM silver nitrate. The AgNPs were oven-dried at 100 degrees C and calcined to obtain a powder that was characterized by X-ray diffractometry and scanning electron microscopy, obtaining AgNPs with an average particle size of 28.44 nm for P. ostreatus and 55.76 nm for P. djamor. [graphics] [graphics]