Rosmarinus officinalis Essential Oil Increases Hair Length and Follicle Diameter of Ultraviolet B-exposed Mice Through VEGF

BACKGROUND: Ultraviolet (UVB) radiation induces hair photoaging by triggering oxidative stress, causing alterations in hair diameter and length, which contribute to the development of senile alopecia. Development of alternative anti-photoaging agents to prevent hair loss from various materials, including natural products, is currently being explored. Rosmarinus officinalis essential oil (ROEO) has been known to have antioxidant and vasodilation properties. However, the effect and mechanism of ROEO on UVB-exposed hair are still unclear. Therefore, this study was conducted to evaluate the effects of ROEO on the hair length and follicle diameter in UVB-exposed mice as well as the skin vascular endothelial growth factor (VEGF) level. METHODS: Thirty male Swiss mice were treated topically with/without paraffin oil, 2% minoxidil, or various concentrations of ROEO, every day for 21 days. Meanwhile, UVB exposure was performed 3×/week. On day 21, the hair length was measured, the skin tissue was collected for hair follicle diameter and VEGF measurements. RESULTS: ROEO contained phenolic, including flavonoids and tannins, as well as non-phenolic antioxidants, including 1.8-cineole, α-pinene, and camphor. The IC50 value of ROEO was 15.977 ppm. Significant higher hair length, follicle diameter, and VEGF level of 10% ROEO+UVB-treated mice were observed, compared with the ones of mice exposed with UVB merely (LSD test, p<0.05). CONCLUSION: Since 10% ROEO could significantly increase hair length, follicle diameter and VEGF level, and contained antioxidant compounds, it can be suggested that ROEO might increase hair length, follicle diameter, and VEGF level through its antioxidant component.