Curcumin-Loaded Liposomes in Gel Protect the Skin of Mice against Oxidative Stress from Photodamage Induced by UV Irradiation

Abstract

Prolonged exposure to ultraviolet (UV) irradiation can cause oxidative stress in the skin, accompanied by rapid immunosuppressive effects, resulting in a peroxidation reaction throughout the body. Curcumin (Cur), as the bioactive compound of turmeric, is a natural polyphenol with potent antioxidant properties but is often overlooked due to its poor solubility and low bioavailability. In this study, curcumin-loaded liposomes in a sodium alginate gel complex preparation were designed to improve the bioavailability of curcumin and to study its preventive effect on photodamage. Cur-loaded liposomes (Cur-L), Cur-loaded gel (Cur-G) based on an alginate matrix, and curcumin-loaded liposomes in gel (Cur-LG) were prepared, and their antioxidant effects and drug diffusion abilities were evaluated. The antioxidant capacity of Cur, Cur-L, Cur-G, and Cur-LG was also studied in a mouse model of photodamage. Cur had the highest antioxidant activity at about 4 mg/mL. Cur-LG at this concentration showed antioxidant effects during 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) and H₂O₂ experiments. During the UV light damage test, Cur-LG demonstrated the ability to effectively neutralize free radicals generated as a result of lipid peroxidation in the skin, serum, and liver, thereby enhancing the overall activity of superoxide dismutase (SOD). In conclusion, using Cur-LG may protect against epidermal and cellular abnormalities induced by UV irradiation.

Keywords: antioxidant; curcumin; liposomes in gel; photodamage.

Figure 1

Scavenging capacity on H₂O₂ and DPPH. (A) Clearance of H₂O₂ by curcumin solution with different concentrations; (B) the scavenging ability of Cur, Cur-L, Cur-G, and Cur-LG on H₂O₂; (C) the relationship between curcumin solution and DPPH scavenging rate. (D) The scavenging ability of Cur, Cur-L, Cur-G, and Cur-LG on DPPH; * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001, # p < 0.05.

Figure 2

Release rates of Cur, Cur-L, Cur-G, and Cur-LG across dialysis membranes.

Figure 3

Cur/Cur-L/Cur-G/Cur-LG prevented macroscopic skin changes in mice induced by UV radiation. (A) The changes on the back skin surface of mice and subcutaneous tissue maps after eight weeks UV radiation; (B) observation of subcutaneous blood vessels of mice at the eighth week; (C) visual scoring of mouse dorsal surface skin. * p < 0.05, *** p < 0.001, # p < 0.05, ## p < 0.01.

Figure 4

(A) Spleen index; (B) inhibitory rate of different samples on MDA production in skin; (C) inhibitory rate of different samples on MDA production in liver; (D) inhibition rate of Cur/Cur-L/Cur-G/Cur-LG on MDA generation in LDL; (E) total vitality of SOD in the skin. * p < 0.05, ** p < 0.01, *** p < 0.001, # p < 0.05, ## p < 0.01, ### p < 0.001.

Figure 5

(A) The relationship between Cur-LG stability and pH; (B) under alkaline pH or the action of catalytic enzymes such as cyclooxygenase and lipoxygenase, curcumin can undergo intramolecular cyclization of phenoxy radical intermediates generated by autoxidation or free radical mediation.