Planta Med 2015; 81 - SL3B_06
DOI: 10.1055/s-0035-1565319

α-Glucosidase inhibiting compounds from Justicia secunda VAHL (Acanthaceae) – from HPTLC bioautography screening to isolation and structure elucidation

BA Theiler 1, S Istvanits 1, M Zehl 1, E Urban 2, L Marcourt 3, LO Espinoza Caisa 4, S Glasl 1
  • 1Department of Pharmacognosy, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
  • 2Department of Pharmaceutical Chemistry, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
  • 3Department of Phytochemistry and Bioactive Natural Products, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva, Switzerland
  • 4Corporación Verde Azul, Santa Prisca OE 3 – 17, 5to Piso, Ofic 27, 170150 Quito, Ecuador

Justicia secunda VAHL belongs to the family of Acanthaceae and is a barely examined species. In Ecuador, the leaves of J. secunda are applied in ethnomedicine against indications related to diabetes [1]. The aim of this study was to screen J. secunda for its potential α-glucosidase inhibiting effect performing a bioautographic HPTLC assay [2]. A methanol extract of leaves was first partitioned successively between solvents of increasing polarity (light petroleum, CH2Cl2, BuOH, H2O). The aqueous fraction showed distinct activity. It was subjected to column chromatography on polystyrene for further fractionation and sugar removal, yielding two subfractions with α-glucosidase inhibiting effects. For final isolation and characterization of pure active compounds, preparative HPTLC and semipreparative HPLC on RP-18e were conducted. MS and extensive NMR measurements led to the structure elucidation of the unknown diastereomers 4RS-{[(2E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl]oxy}-2RS,5-dihydroxy-3-oxopentanoic acid (1) and the recently published diastereomers secundarellone B and C (2) [3].

References:

[1] Personal communication with “Corporación Verde Azul” in Ecuador.

[2] Simões-Pires CA, Hmicha B, Marston A, Hostettmann K. A TLC bioautographic method for the detection of α- and β-glucosidase inhibitors in plant extracts. Phytochem Anal 2009; 6: 511 – 515.

[3] Theiler BA, Revoltella S, Zehl M, Dangl C, Espinoza Caisa LO, König J, Winkler J, Urban E, Glasl S. Secundarellone A, B, and C from the leaves of Justicia secunda VAHL. Phytochem Lett 2014; doi: 10.1016/j.phytol.2014.05.007.