Molecular Network Guided Cataloging of the Secondary Metabolome of Selected Egyptian Red Sea Soft Corals

Abstract

Soft corals are recognized as an abundant source of diverse secondary metabolites with unique chemical features and physiologic capabilities. However, the discovery of these metabolites is usually hindered by the traditional protocol which requires a large quantity of living tissue for isolation and spectroscopic investigations. In order to overcome this problem, untargeted metabolomics protocols have been developed. The latter have been applied here to study the chemodiversity of common Egyptian soft coral species, using only minute amounts of coral biomass. Spectral similarity networks, based on high-resolution tandem mass spectrometry data, were employed to explore and highlight the metabolic biodiversity of nine Egyptian soft coral species. Species-specific metabolites were highlighted for future prioritization of soft coral species for MS-guided chemical investigation. Overall, 79 metabolites were tentatively assigned, encompassing diterpenes, sesquiterpenes, and sterols. Simultaneously, the methodology assisted in shedding light on newly-overlooked chemical diversity with potential undescribed scaffolds. For instance, glycosylated fatty acids, nitrogenated aromatic compounds, and polyketides were proposed in Sinularia leptoclados, while alkaloidal terpenes and N-acyl amino acids were proposed in both Sarcophyton roseum and Sarcophyton acutum.

Discriminative Metabolomics Analysis and Cytotoxic Evaluation of Flowers, Leaves, and Roots Extracts of Matthiola longipetala subsp. livida

“…The annotation of the amino acids was derived from the abundant fragments of the protonated ions and their corresponding derivatives arising from either losing H 2 O (−18 Da) yielding their residue mass or the loss of (H 2 O + CO) (−46 Da) producing their immonium ions [84] leading to the detection of five amino acids including arginine (1), proline (2), leucine/isoleucine (17), phenylalanine (22), tryptophan (34), and three amino acids derivatives; methyl proline (5), dimethyl proline (6) and tryptophan N-glucoside (31), mainly distributed among the three plant organs. Similarly, five organic acids were detected as self-looped nodes either in the negative or positive FBMNs and identified as hydroxyl glutaric acid (8), malic acid (13), citraconic acid (methyl maleic acid) (15), dimethyl malate (38), and cinnamic acid (21) (Table 1).…”

“…UPLC-HRMS/MS offers the advantages of high efficiency, reproducibility, and shorter analysis [ 11 ]. Additionally, advances in the data analysis tools, such as molecular networks through the Global Natural Products Social Molecular Networking (GNPS) [ 12 ], allow for the visual display of the constitutive metabolome among samples and the propagation of metabolites annotation [ 13 ].…”

Molecular networking-guided investigation of the secondary metabolome of four Morus species and their in vivo neuroprotective potential for the mitigation of Alzheimer's disease

“…The acquired mass spectrometry data will be mined by feature-based molecular networking (FBMN) through the GNPS (Global Natural Product Social Molecular Networking) platform (https://gnps.ucsd.edu) to facilitate the annotation step and to visualize the metabolite discrepancies among the studied Morus species. 11,12 2. Materials and methods…”