The infections caused by the HSV-1 virus induce lesions on the lips, mouth, face, and eye. In this study, an ethosome gel loaded with dimethyl fumarate was investigated as a possible approach to treat HSV-1 infections. A formulative study was conducted, evaluating the effect of drug concentration on size distribution and dimensional stability of ethosomes by photon correlation spectroscopy. Ethosome morphology was investigated by cryogenic transmission electron microscopy, while the interaction between dimethyl fumarate and vesicles, and the drug entrapment capacity were respectively evaluated by FTIR and HPLC. To favor the topical application of ethosomes on mucosa and skin, different semisolid forms, based on xanthan gum or poloxamer 407, were designed and compared for spreadability and leakage. Dimethyl fumarate release and diffusion kinetics were evaluated in vitro by Franz cells. The antiviral activity against HSV-1 was tested by plaque reduction assay in Vero and HRPE monolayer cells, while skin irritation effect was evaluated by patch test on 20 healthy volunteers. The lower drug concentration was selected, resulting in smaller and longer stable vesicles, mainly characterized by a multilamellar organization. Dimethyl fumarate entrapment in ethosome was 91% w/w, suggesting an almost total recovery of the drug in the lipid phase. Xanthan gum 0.5%, selected to thicken the ethosome dispersion, allowed to control drug release and diffusion. The antiviral effect of dimethyl fumarate loaded in ethosome gel was demonstrated by a reduction in viral growth both 1 h and 4 h post-infection. Moreover, the patch test demonstrated the safety of the ethosomal gel applied on the skin.

Protein fibril formation is of considerable interest due to the association of fibrils with many neurodegenerative diseases as well as non-neuropathic amyloidosis. In this study, the effects of individual phenolic compounds and their mixtures—including caffeic acid (CC), quercetin (Que), and resveratrol (Res)—on the fibrillation of lysozyme (Lys) were investigated using Fourier transform infrared (FTIR) and vibrational circular dichroism (VCD) spectroscopy. These phenolic compounds are known as potent modulators, particularly inhibitors, of fibrillation in various proteins and peptides. While their anti-fibrillar activity has been extensively studied via the Thioflavin T (ThT) fluorescence assay, here FTIR and VCD spectroscopy are employed for a comprehensive, label-free investigation of their effects. The results indicate that CC, Que, and Res influence Lys fibrillogenesis in ways that depend on the phenol concentration, their combination (mixing ratios), and the experimental conditions. In particular, Lys was observed to form left-handed fibrils under these conditions in the presence of these phenolic compounds, as evidenced by the VCD signal. Furthermore, a comparison was made of the inhibitory effects of the individual phenols and their mixtures on Lys fibril formation: CC and Res were more effective inhibitors than Que. Interestingly, an equimolar mixture of CC and Res exhibited a strong synergistic inhibitory effect on fibrillation, whereas the combination of CC with Que showed an antagonistic effect. Overall, this study provides deeper insights into how specific polyphenolic compounds influence protein fibrillation processes, offering valuable information for developing therapeutic interventions targeting protein aggregation-associated disorders.