Chemical constituents isolated from the aerial parts of Helleborus cyclophyllus (A. Braun) Boiss. (Ranunculaceae), evaluation of their antioxidant and anti-inflammatory activity in vitro and virtual screening of molecular properties and bioactivity score

Abstract

Chemical investigation of ethyl acetate extract from the aerial parts of Helleborus cyclophyllus (A.Braun) Boiss. led to the isolation of ten natural products, and their structures were identified to be: 2-deoxy-D-ribono-1,4-lactone (1), 2-O-feruloyl-L-malate (2), three flavonoids: quercetin 3-O-β-D-galactopyranoside (3), quercetin 3-O-6′′-(3-hydroxy-3-methyl-gloutaryl)-β-D-glucopyranoside (4) and quercetin 3-O-(2‴-caffeoylsophoroside) (5), 6-O-caffeoyl-1-O-p-coumaroyl-β-D-glucopyranoside (6), two ecdysteroids: 20-hydroxyecdysone (7) and polypodine B (8) and two bufadienolides: deglucohellebrin (9) and hellebrin (10), on the basis of MS and NMR spectra. This is the first report on the occurrence of compounds (2)-(6) in the genus Helleborus. The chemotaxonomic significance of these compounds was summarised. Bioactivity score, molecular and pharmacokinetic properties of the isolated compounds were calculated by online computer software program Molinspiration. Compounds showed promising bioactivity scores for drug targets. Moreover, some of the isolated phenolic compounds were tested for their antioxidant and antiinflammatory activities. Tested compounds presented antioxidant ability correlated to the presence of the phenolic hydroxyl groups.

Graphical Abstract

Keywords:

• Helleborus cyclophyllus
• Ranunculaceae
• triterpenoids
• flavonoids

Acknowledgments

The authors are grateful to Professor Dr. Haralambos Katerinopoulos (Department of Chemistry, University of Crete) for giving them permission to record some of the NMR spectra and all the MS spectra in his laboratory and to Dr. Nikos Krigas (Researcher in National Agricultural Research Foundation, Laboratory for the Conservation and Evaluation of Native and Floricultural Species, Thermi, Thessaloniki Greece) for the identification of the plant material.

Disclosure statement

No potential conflict of interest was reported by the authors.