Hexagonosides A-F: Pregnane glycosides isolated from Caralluma hexagona

Osama G Mohamed; Akram A Shalabi; Ali M El Halawany; Ashootosh Tripathi; Essam Abdel-Sattar

doi:10.1016/j.phytochem.2023.113903

Hexagonosides A-F: Pregnane glycosides isolated from Caralluma hexagona

Phytochemistry. 2024 Jan:217:113903. doi: 10.1016/j.phytochem.2023.113903. Epub 2023 Nov 2.

Authors

Osama G Mohamed¹, Akram A Shalabi², Ali M El Halawany², Ashootosh Tripathi³, Essam Abdel-Sattar⁴

Affiliations

¹ Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Kasr el Aini St., Cairo, 11562, Egypt; Natural Products Discovery Core, Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA. Electronic address: ogomaa@umich.edu.
² Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Kasr el Aini St., Cairo, 11562, Egypt.
³ Natural Products Discovery Core, Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA; Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109, USA. Electronic address: ashtri@umich.edu.
⁴ Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Kasr el Aini St., Cairo, 11562, Egypt. Electronic address: essam.abdelsattar@pharma.cu.edu.eg.

PMID: 37918619
DOI: 10.1016/j.phytochem.2023.113903

Abstract

Chemical investigation of Caralluma hexagona Lavranos, a wild plant growing in Yemen, led to the isolation of four previously undescribed acylated pregnane glycosides, hexagonosides A-D (1-4), together with two sets of mixtures (hexagonosides E and F), each set consists of three interconvertible pregnane glycoside isomers, hexagonosides E (5a-c) and F (6a-c). The chemical structures of the isolated pregnane glycosides were elucidated by extensive 1D/2D NMR and HRESI-MS analysis, featuring 6'-O-benzoyl-1'-O-β-glucosyl residue at aglycone C-20; while aglycone C-3 was substituted with disaccharide sugar chain (1, 2, 5a-c) or a trisaccharide sugar chain (3, 4, 6a-c). Metabolites E and F included an extra benzoyl substitution in C-20 glucosyl residue which is migrating between the OH groups of C-2', C-3' and C-4' resulting in equilibrating conformations (5a-c and 6a-c) when incubated in HPLC solvent, which we confirmed by the analytical study.

Keywords: Acyl migration; Apocynaceae; Carallumahexagona; Hexagonosides; Pregnane glycosides.

MeSH terms

Apocynaceae* / chemistry
Glycosides* / chemistry
Molecular Structure
Pregnanes / chemistry
Sugars

Substances

pregnane glycoside
7-deoxy-13-dihydroadriamycinone
Glycosides
Pregnanes
Sugars