Planta Med 2015; 81 - PM_07
DOI: 10.1055/s-0035-1565384

Bioactive phenylethanoid glycosides from Digitalis davisiana Heywood

V Murat Kutluay 1, M Inoue 2, I Saracoglu 1
  • 1Hacettepe University, Faculty of Pharmacy, Department Pharmacognosy, Ankara, Turkey
  • 2Aichi Gakuin University, School of Pharmacy, Laboratory of Medicinal Resources, Nagoya, Japan

In the Flora of Turkey, the genus Digitalis is represented by nine species [1]. In this research aerial parts of Digitalis davisiana Heywood was studied phytochemically on the basis of LXR (Liver x receptor) ligand activity, free radical scavenging and cytotoxic activities guided fractionation. Methanol extract applied to polyamide column chromatography for fractionation. Due to examination of mentioned bioactivity tests, active fractions were detected. Radical scavenging activity was tested against DPPH, NO, SO radicals. IC50 values of methanolic extract for tested radicals were found to be; 133.8, 309.9, 1560 µg/mL, respectively. Cytotoxic activity was tested against HEp-2, HepG2 and 3Y1 cell lines by MTT method [2]. IC50 values were 50.8, 211.4 and 94.7 µg/mL respectively. LXR ligand activity was tested by a LXRα luciferase reporter assay on HEK293 cells [3]. Since methanol extract showed cytotoxicity, LXR ligand activity couldn't be determined. When fractions tested in lower concentrations moderate activity was detected. After evaluating the bioactivity test results, isolation studies started from active, phenylethanoid glycosides rich fractions. Studies resulted in the isolation of six phenylethanoid glycosides. Lugrandoside, maxoside and purpureaside E were identified by extensive NMR techniques. Structural determination studies on the other active compounds are in progress.

Acknowledgements: Vahap Murat Kutluay was supported by research grant from The Scientific and Technological Research Council of Turkey (2214/A,2211).

References:

[1] Davis PH (1978) Flora of Turkey and the East Eagean Islands, University Press, Edinburg, Vol 6.

[2] Saracoglu I, et al. Studies on constituents with cytotoxic and cytostatic activity of two Turkish medicinal plants Phlomis armeniaca and Scutellaria salviifolia. Biol Pharm Bull 1995; 18: 1396 – 1400

[3] Kotani H, et al. Identification of a naturally occurring rexinoid, honokiol, that activates the retinoid X receptor. J. Nat. Prod. 2010; 73: 1332 – 1336.