Anti-eczematic and molecular modeling of anthraquinones isolated from the seeds of Asphodelus microcarpus salzm. viv. growing in Egypt

Background: Eczema or atopic dermatitis is a widely spread skin disorder; the topical application of corticosteroids is the first choice for treatment. Natural products have a great contribution in the treatment of this disease; Asphodelus microcarpus seeds are rich in anthraquinones and known to possess both anti-inflammatory and antidermatitis effects. Objective: The objective of the study is to investigate the anti-eczematic activity, acute toxicity, and molecular modeling of A. microcarpus seeds. Materials and Methods: Nuclear magnetic resonance, ultraviolet, and mass spectroscopy were applied for characterization of isolated metabolites; induction of eczema was conducted by 2% and 0.2% w/v dinitrochlorobenzene in acetone; eczema was treated with topical application of the different seed extracts in the form of ointments (1% w/w); Swiss albino mice (25–30 g) were used for the determination of LD50and anti-eczematic effect. Docking studies were performed by Molecular Operating Environment software. Results: A. microcarpus seed extract exhibited promising ant-eczematic activity, six anthraquinones were isolated from chloroform portion and characterized as 10,7'-bichrysophanol (1), asphodelin (2), chrysophanol-8-O-methyl ether (3), chrysophanol (4), physcion (5), and emodin (6). Compounds 1, 3, and 5 exerted significant anti-eczematic effect. Conclusion: Six known anthraquinone derivatives were isolated and characterized for the first time from the seeds of A. microcarpus. Chloroform fraction (1% w/w) showed significant anti-eczematic effect compared to standard mometasone furoate (0.1 w/w). The docking study proved the anti-eczematic activity of anthraquinone content by their affinity to the target human histamine H1receptor.