Phytochemical profiles and antimicrobial activities of Allium cepa red cv. and A. sativum subjected to different drying methods: A comparative MS-based metabolomics
Date
2017
Journal Title
Journal ISSN
Volume Title
Type
Article
Publisher
Institute of Electrical and Electronics Engineers Inc.
MDPI AG
MDPI AG
Series Info
Molecules
22
22
Scientific Journal Rankings
Abstract
Plants of the Allium genus produce sulphur compounds that give them a characteristic (alliaceous) flavour and mediate for their medicinal use. In this study, the chemical composition and antimicrobial properties of Allium cepa red cv. and A. sativum in the context of three different drying processes were assessed using metabolomics. Bulbs were dried using either microwave, air drying, or freeze drying and further subjected to chemical analysis of their composition of volatile and non-volatile metabolites. Volatiles were collected using solid phase micro-extraction (SPME) coupled to gas chromatography-mass spectrometry (GC/MS) with 42 identified volatiles including 30 sulphur compounds, four nitriles, three aromatics, and three esters. Profiling of the polar non-volatile metabolites via ultra-performance liquid chromatography coupled to high resolution MS (UPLC/MS) annotated 51 metabolites including dipeptides, flavonoids, phenolic acids, and fatty acids. Major peaks in GC/MS or UPLC/MS contributing to the discrimination between A. sativum and A. cepa red cv. were assigned to sulphur compounds and flavonoids. Whereas sulphur conjugates amounted to the major forms in A. sativum, flavonoids predominated in the chemical composition of A. cepa red cv. With regard to drying impact on Allium metabolites, notable and clear separations among specimens were revealed using principal component analysis (PCA). The PCA scores plot of the UPLC/MS dataset showed closer metabolite composition of microwave dried specimens to freeze dried ones, and distant from air dried bulbs, observed in both A. cepa and A. sativum. Compared to GC/MS, the UPLC/MS derived PCA model was more consistent and better in assessing the impact of drying on Allium metabolism. A phthalate derivative was found exclusively in a commercial garlic preparation via GC/MS, of yet unknown origin. The freeze dried samples of both Allium species exhibited stronger antimicrobial activities compared to dried specimens with A. sativum being in general more active than A. cepa red cv. � 2017 by the authors.
Description
Scopus
Keywords
October University for Modern Sciences and Arts, University for Modern Sciences and Arts, MSA University, جامعة أكتوبر للعلوم الحديثة والآداب, Anti-microbial, Drying, Flavonoids, Garlic, Metabolomics, Onion, Organosulphur, antiinfective agent, flavonoid, sulfur derivative, chemistry, comparative study, garlic, mass spectrometry, metabolism, metabolomics, onion, procedures, Anti-Infective Agents, Flavonoids, Garlic, Mass Spectrometry, Metabolomics, Onions, Sulfur Compounds