Therapeutic effects of chamomile volatile oil nanoemulsion/Bletilla striata polysaccharides gels on atopic dermatitis

Atopic dermatitis (AD) is a prevalent chronic skin condition characterized by complex immune responses. Chamomile possesses potent anti-inflammatory properties and has been widely used in treating various skin diseases. This study aimed to assess the therapeutic benefits of chamomile volatile oil nanoemulsion gels (CVO-NEGs) for the treatment of AD. Chamomile volatile oil nanoemulsions (CVO-NEs) were prepared using the phase transition method, yielding spherical nanoparticles with a particle size of 19.07 nm. Subsequently, Bletilla striata polysaccharides were employed to encapsulate CVO-NEs, resulting in the formation of CVO-NEGs. In vivo studies demonstrated that the preparation of CVO-NEGs enhanced the biological activity of volatile oil in AD therapy. Histopathological results indicated that CVO-NEGs reduced skin damage, epidermal thickness, and mast cell infiltration. CVO-NEGs suppressed IgG production and reduced the levels of cytokines, including TNF-α, IL-4, and IFN-γ, in AD mice. Furthermore, flow cytometry revealed that CVO-NEGs were involved in regulating the differentiation of CD4⁺ T cell subsets. The immune imbalance of Th1/Th2 in AD mice can be controlled, resulting in a reduction in the hypersensitivity reaction caused by excessive Th2 activation. In conclusion, the present study confirms that CVO-NEGs have the potential to serve as an effective alternative treatment for AD.