Identification of Phenolic and Carotenoid Compounds in Carica papaya L. 'Maradol' Using Liquid Chromatography - Mass Spectrometry

Plant phenolic and carotenoid compounds are known for their beneficial effects on human health, and they are present in a great variety of fruits and vegetables. The profile of bioactive compounds in papaya fruit has not been completely elucidated and research has been focused on characterization of mature fruit flesh composition and proteolitic enzymes with industrial applications. The objective of this work was to identify potential bioactive compounds previously related to health improvement, in papaya peel and flesh tissues during storage at 25°C. Samples of peel and flesh tissue of C. papaya fruits were submitted to solvent extraction and hydrolysis in order to identify free and conjugated phenolics by liquid chromatography/diode array detector coupled to electro spray ionization mass spectrometry (LC/DAD-MS-ESI). Caffeic acid, protocatechuic acid-hexoside, sinapic acid, quercetin-3-O-rutinoside, ferulic acid, myricetin, quercetin, isorhamnetin, kaempferol, caffeoylhexose-deoxyhexose, caffeoylhexoside and gallic acid-deoxyhexoside phenolics were found in peel extracts while caffeic acid, protocatechuic acid and gallic acid hexosides were present in the flesh. Carotenoids were identified in the flesh by LC/DAD coupled to atmospheric pressure ionization mass spectrometry (LC/DAD-MS-APCI). Lycopene, β-criptoxhantin and β-carotene were the most abundant carotenoids in that order. No significant differences were observed in phenolic profile during storage; however, lycopene and β-criptoxhantin levels tend to increase in storage. Identified phenolic and carotenoid compounds have proved to act as potent antioxidants in biological systems, and some are presumed to act as preventative anticarcinogens agents in vitro and in vivo. The presence of these compounds could explain the health benefits attributed to this fruit, and opens future studies towards mode of action elucidation in biological systems.