Anticholinesterase and anti-inflammatory constituents from Caralluma awdeliana, a medicinal plant from Yemen

• Published in: Steroids 2023-05, Vol.193, p.109198-109198, Article 109198
• Main Authors: El-Shiekh, Riham A., Shalabi, Akram A., Al-Hawshabi, Othman S.S., Ayman Salkini, Mohamad, Abdel-Sattar, Essam
• Format: Article
• Language: English
• Subjects: Anti-Inflammatory Agents - pharmacology; Apocyanaceae; Apocynaceae; Awdeliosides A and B; Caralluma awdeliana; Caratuberoside B and D; Cholinesterase Inhibitors - pharmacology; Flavones; Glycosides; In Vitro Anticholinesterase and anti-inflammatory; Plant Extracts - pharmacology; Plants, Medicinal; Pregnane Glycosides; Pregnanes; Yemen
• ISSN: 0039-128X; 1878-5867
• DOI: 10.1016/j.steroids.2023.109198

[Display omitted] •The dichloromethane fraction Caralluma awdeliana afforded four pregnane glycosides using a bio-guided isolation approach.•Two glycosides were new and named awdeliosides A and B.•The fractions and the compounds were tested for in vitro anticholinesterases and anti-inflammatory activities.•Awdelioside B showed potent selective inhibitory effect against COX-1.•Awdelioside B showed a moderate anticholinesterase effect against BChE enzyme. From the dichloromethane (DCM) fraction of the crude ethanolic extract of Caralluma awdeliana, four pregnane glycosides and a flavone glycoside were isolated using a bio-guided isolation approach. The different extracts of C. awdeliana were subjected to in vitro enzyme inhibitory assays of anticholinesterases (AChE and BChE) and anti-inflammatory (COXs and 5-LOX). The highest inhibitory activity was exhibited by DCM fraction against COX-1, COX-2, and 5-LOX with IC50 of 4.8 ± 0.5 μg/mL, 0.68 ± 0.2 μg/mL, and 39.5 ± 3.0 μg/mL, respectively. The DCM showed also a moderate activity against AChE (IC50 384.72 ± 3.6 μg/mL), and BChE (IC50 384.72 ± 3.6 μg/mL). The repeated chromatography of DCM fraction resulted in the isolation of two new pregnane glycosides, namely awdeliosides A (1) and B (4), two known ones, namely caratuberosides B and D, along with the known flavone glycoside identified as luteolin 4 -O-neohesperidoside. All the isolated compounds were tested for their in vitro enzyme inhibitory assays. Among the isolated compounds, awdelioside B (4) showed the most potent effect against COX-1 with IC50 value of 10.99 ± 0.35 μM, compared to standard celecoxib (IC50 230.74 ± 2.62 μM). All the isolated compounds showed weak anticholinesterase, except a moderate activity observed for awdelioside B (4) against BChE with IC50 value of 15.63 ± 3.5 μM, compared to standard donepezil (IC50 0.77 ± 0.0088 μM).