Acylated Flavonoid Glycosides are the Main Pigments that Determine the Flower Colour of the Brazilian Native Tree Tibouchina pulchra (Cham.) Cogn

  • Molecules. 2019 Feb 16;24(4):718. doi: 10.3390/molecules24040718.
Fernanda Mendes Rezende  1 ,  Marcelo José Pena Ferreira  2 ,  Mads Hartvig Clausen  3 ,  Magdalena Rossi  4 ,  Claudia Maria Furlan  5
Affiliations
  • 1. Botany Department, Institute of Bioscience, University of São Paulo (USP), São Paulo 05508-060, Brazil. [email protected].
  • 2. Botany Department, Institute of Bioscience, University of São Paulo (USP), São Paulo 05508-060, Brazil. [email protected].
  • 3. Center for Nanomedicine and Theranostics, Department of Chemistry, Technical University of Denmark, Kgs. 2800 Lyngby, Denmark. [email protected].
  • 4. Botany Department, Institute of Bioscience, University of São Paulo (USP), São Paulo 05508-060, Brazil. [email protected].
  • 5. Botany Department, Institute of Bioscience, University of São Paulo (USP), São Paulo 05508-060, Brazil. [email protected].
PMID: 30781526 DOI: 10.3390/molecules24040718
Abstract

Tibouchina pulchra (Cham.) Cogn. is a plant native to Brazil whose genus and family (Melastomataceae) are poorly studied with regards to its metabolite profile. Phenolic Pigments of pink flowers were studied by ultra-performance liquid chromatography with a photodiode array detector and electrospray ionization quadrupole time-of-flight mass spectrometry. Therein, twenty-three Flavonoids were identified with eight Flavonols isolated by preparative high-performance liquid chromatography and analysed by one- and two-dimensional nuclear magnetic resonance. Kaempferol derivatives were the main Flavonols, encompassing almost half of the detected compounds with different substitution patterns, such as glucoside, pentosides, galloyl-glucoside, p-coumaroyl-glucoside, and glucuronide. Concerning the anthocyanins, petunidin p-coumaroyl-hexoside acetylpentoside and malvidin p-coumaroyl-hexoside acetylpentoside were identified and agreed with previous reports on acylated anthocyanins from Melastomataceae. A new kaempferol glucoside was identified as kaempferol-(2''-O-methyl)-4'-O-α-d-glucopyranoside. Moreover, twelve compounds were described for the first time in the genus with five being new to the family, contributing to the chemical characterisation of these taxa.

Keywords
Melastomataceae; anthocyanin; flavonol; kaempferol.
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