Extraction optimization, identification using UPLC-tandem mass spectrometry, and antioxidant properties of polyphenols from the fruit body of Morchella sextelata.

Abstract

Polyphenols, as important active ingredients in edible fungi, have many beneficial functions. As rare edible fungi, Morchella spp., are highly popular due to their nutritional value and unique flavor. However, most Morchella have not yet been artificially cultivated due to their special biological characteristics, resulting in limited research on polyphenols in artificially cultivated Morchella. In this study, the extraction parameters of polyphenols from artificially cultivated Morchella sextelata were optimized using response surface methodology, the polyphenol components were analyzed via UPLC‒tandem mass spectrometry, and their antioxidant properties were determined in vitro. The optimal extraction process parameters were as follows: ethanol concentration, 43%; solid‒liquid ratio, 1:41gmL-1; extraction temperature, 52°C; extraction time, 2h; rotation speed, 180rmin-1; and extraction frequency, twice. The optimized extraction parameters resulted in a polyphenol yield of 4.82mgg-1, a 69.97% increase. Fourteen phenolic compounds were identified: gallic acid, protocatechuic acid, dl-4-hydroxyphenyllactic acid, methyl 2,4-dihydroxyphenylacetate, salicylic acid, 4-hydroxybenzaldehyde, 4-hydroxyacetophenone, eucommiol, luteolin, ethylparaben, hinokiflavone, amentoflavone, propyl 4-hydroxybenzoate, and 2,6-di-tert-butylphenol. The EC50 values of 1,1-diphenyl-2-picrylhydrazyl (DPPH)· scavenging ability, reducing power and ferrous ion chelating ability of polyphenols were 2.70, 30.98, and 72.06µgmL-1, respectively. These findings indicated that polyphenols had a significantly stronger ability to scavenge DPPH· compared with their reducing power and ability to chelate ferrous ions. The results of this study provide a solid foundation for the subsequent study of function of M. sextelata polyphenols as well as a theoretical basis for the further development and utilization of M. sextelata, which will help promote healthy development of Morchella industry. PRACTICAL APPLICATION: The extraction, composition, and antioxidant properties of polyphenols from Morchella sextelata were identified, which provides a theoretical basis for better utilization of Morchella resources.