Cryo-Ground Mango Kernel Powder: Characterization, LC-MS/MS Profiling, Purification of Antioxidant-Rich Gallic Acid, and Molecular Docking Study of Its Major Polyphenols as Potential Inhibitors against SARS-CoV-2 Mpro.

Abstract

Mango processing waste (MPW) is an inexpensive and rich source of valuable substances. Hence, the mango kernel powder (MKP) from four cultivars (Chausa, Neelum, Barahmasi, and Dashehari) was characterized for the selection of the best cultivar. The MKP of the best cultivar (Dashehari) was analyzed for the profiling of polyphenols using LC-MS/MS in both modes of ionization (positive and negative) and indicated the presence of 50 compounds with specific retention times. After identification, gallic acid (GA), an important industrial compound, was targeted and purified followed by its confirmation using NMR (600 MHz) and HRMS. The antioxidant activity (IC50: 1.96 μg/mL) of extracted GA proposes its use as a natural antioxidant in novel food formulations. Additionally, SARS-CoV-2 main protease (Mpro) was selected for molecular docking based virtual screening of seven major polyphenols (MKP), and the results were compared with hydroxychloroquine. The docking scores of targeted polyphenols revealed that three compounds (epicatechin, mangiferin, and quercetin) exhibited appreciable proteolytic activity against Mpro. In this way, it is a favorable approach toward environmental safety on the standpoint of green chemistry owing to the use of food processing waste and elimination of the waste dumping/composting problems.