Mass Spectrometry Based Structural Characterization of Potential Antioxidant Molecules from Marine Sources and their Effect on Protein Carbonylation

Abstract

Ocean covers most of the earth s surface and is a diverse environment containing several organisms that produce potential bioactive compounds. More than 30,000 compounds with unique structure and functional activities have been studied so far. Some of these molecules are found to be pharmacologically active and are effective against diseases including inflammation, cancer, HIV and neurodegenerative disorders. Additionally, several attempts have been made to explore marine sources to identify unique antioxidant prototypes that are absent in terrestrial habitat (Nair et al., 2014). Due to the extreme environmental factors where they survive, marine organisms are known to produce compounds that protect themselves from such stressful conditions. Most of the marine algae in this regard have found their way into traditional medicines and diet due to their radical scavenging property. This panel of natural sources mainly consists of Chlorophyta (green algae), Phaeophyta (brown algae) and Rhodophyta (red algae). Examples of the molecules with significant radical scavenging property include alkaloids, lipopeptides, phenolics, pigment proteins and terpenoids (Takamatsu et al., 2003). Nevertheless, there are considerable challenges involved in the isolation and structural characterization of these compounds.As already known, the bioactivity of the molecules strongly depends on their structure which is characterized by the presence of chromophores, specific bonds, functional groups and their position. Among the different methods utilized for achieving the structural data, mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy are the most prominent methods (Gomes et al., 2017). Compared to NMR, MS has already demonstrated its power and utility in elucidating unknown molecules by providing their accurate masses, isotopic patterns and structural compositions (Kildgaard et al., 2014). Overproduction of free radicals or reactive oxygen species (ROS) in a biological system leads to oxidative stress, that plays..