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Application of Self-Organizing Maps generated from Molecular Descriptors of Flavonoid in the Chemotaxonomy of the Asteraceae Family
* 1 , * 1 , 1 , 2
1  Federal University of ParaIba
2  UNIVERSITY OF SÃO PAULO

Abstract:

The Asteraceae family belongs to the Asterales order, it consists of approximately 1,600 genera and 24,000 species, divided into 12 subfamilies and 44 tribes, is one of the largest families of angiosperms in the world, except Antarctica. Asteraceae is remarkable the presence of flavonoids, these have the necessary requirements to be used successfully in chemotaxonomy because are found in abundance in the Asteraceae, presents structural diversity, are stable structures and relatively easy to identify, therefore can be used as taxonomic markers. The aim of this study is to classify Asteraceae tribes based on the number of occurrences of flavonoids from our in-house databank (available at www.sistematx.ufpb.br) using descriptors calculated by DRAGON 7.0 software. The 2371 botanical occurrences with respective 74 molecular fragment descriptors were used as input data in SOM Toolbox 2.0 (Matlab) to generate Self-Organizing Maps (SOMs), classifying five tribes: tribes Anthemideae (A), Gnaphalieae (G), Tageteae (T), Senecioneae (S) and Carduoideae (CR).  The descriptor with positive contribution to the region where the flavonoids isolated from the tribes are located are: RFD that represents the ring fusion density; nArOH that represents the number of aromatic hydroxyls; nCIC descriptors which represent the number of rings in one molecule; NNRS representing the standard number of ring systems; nR05 which represents the number of 5-membered rings; nCbH representing the number of C (sp2) benzene unsubstituted; nHBonds which represents the number of intramolecular H bonds (O) and C-019 represents = CRX (= represents a double bond, R represents H and CH3, X represents oxygen atom).

 

Keywords: Asteraceae, flavonoids, chemotaxonomy, databank, descriptors, Self-Organizing Maps
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