Study on the Antioxidant Effect of Shikonin-Loaded β-Cyclodextrin Forming Host-Guest Complexes That Prevent Skin from Photoaging

When the skin is overexposed to ultraviolet rays, free radicals will accumulate in the skin, causing lipid damage and even inducing photoaging of the skin. Combination therapy with antioxidant drugs is a good choice for topical treatment of skin photoaging due to its special physiological structure. In this paper, shikonin was encapsulated in β-cyclodextrin (SH-β-CD) by the precipitation crystallization method, which delayed the release of the drug and increased drug solubility. The average diameter of SH-β-CD was 203.0 ± 21.27 nm with a zeta potential of -14.4 ± 0.5 mV. The encapsulation efficiency (EE%) was 65.9 ± 7.13%. The results of the in vitro permeation across the dialysis membrane and ex vivo transdermal release rates were 52.98 ± 1.21% and 88.25 ± 3.26%, respectively. In vitro antioxidant and antilipid peroxidation model assay revealed the antioxidant potential of SH and SH-β-CD. In the mice model of skin photoaging, SH and SH-β-CD had a recovery effect on the skin damage of mice, which could significantly increase the superoxide dismutase (SOD) activity in the skin. Briefly, SH-β-CD had an obvious therapeutic effect on the skin photoaging of mice caused by UV, and it is promising in skin disease treatment and skin care.

Structure performance of UVA and UVB light irradiated poly-p-phenylene benzobisoxazole fiber (PBO)

By UVA and UVB irradiating, the performance of poly-p-phenylene benzobisoxazole (PBO) fiber is changed with an increase in irradiation time, and the surface morphology, chemical structure, mechanical performance and thermal properties of the fiber are poorer. After 320-h irradiation, the properties of the PBO fiber irradiated by UVB are stronger than those irradiated by UVA. The strength of PBO fiber irradiated by UVB and UVA declined by 40% and 20%, respectively, than that of non-irradiated fiber. The roughness of fiber surface improved, and there was corrosion on the surface of PBO fiber irradiated by UVB. After the UV irradiation, the degree of macromolecule crystallinity and orientation changed, the macromolecule chain is broken, new groups (-NO2) are produced in the PBO fiber, and the temperature (660°C) of the thermolysis is decreased by 100°C from that of fibril.