Identification and isolation of anti-pneumonia bioactive compounds from Opuntia ficus-indica, fruits waste peels.
Prickly pear fruit peel constitutes a high-percentage of the fruit which could be a natural, economic agro-industrial waste in the nutraceutical industry. This study aimed to isolate and characterize the main constituents, and evaluate its antibacterial activity. A methanol extract was successively fractionated using hexane, chloroform & ethyl acetate. An n-hexane fraction was evaluated for its fatty acid content using GC-MS showing linolenic acid “Omega-3” as the major fatty acid (60.56%), while an ethyl acetate fraction was analyzed using UPLC-ESI-MS/MS resulting in identification of (6) phenolic acids and (9) flavonoids; Caffeic acid (43.69%) and Quercetin (14%) were found the most abundant respectively. An ethyl acetate fraction was subjected to column chromatography resulting in isolation of four flavanols viz astragalin (1), quercetin5,4'-dimethyl ether (2), isorhamentin3-O-glucoside (3) & isorhamentin (4). Antibacterial evaluation revealed that the EtOAc fraction is the most potent active fraction against the selected pneumonia pathogens and quercetin5,4'-dimethyl ether (2) is the most active among the isolated compounds. Virtual docking of the isolated compounds showed promising in silico anti-quorum sensing efficacy; that could represent natural antibacterial agents. These findings indicate that the unused waste part of prickly pear fruits possesses valuable constituents with beneficial potential against some pneumonia pathogens.