###### Abstract  
Sesame oil has been widely used for centuries. It is not only used as a kitchen ingredient, but it is also used to apply to the skin. Sesame oil contains natural compounds such as sesamol, sesamolin and sesamide, which have the ability to reflect or absorb certain UV rays. These substances can act as UV filters, helping to minimize the effects of harmful UV radiation on the skin. The aim of the study was to investigate the radioprotective/sun protection properties of sesame oil. The influence of sesame oils from different manufacturers on the directional reflectance of the skin was analyzed at various time intervals. To assess the sunscreen properties of the oil, a new technique was used: the 410-Solar hemispherical directional reflectometer. Sesame oil can be used in sunscreen preparations, but only when combined with other, more powerful ingredients. The oil itself is not sufficient protection against solar radiation. The study revealed no significant disparities in performance between the tested sesame oils from diverse manufacturers. sesame oil; ultraviolet radiation; directional reflectance; sun protection properties +
Footnote †: journal: Medical  
decreases cytotoxicity, ROS levels, lipid peroxidation, and oxidative DNA damage in skin fibroblasts. Sesamol also reduces the expression of TRP-1 and TRP-2 proteins, which are involved in melanin synthesis, and inhibits the expression of MITF, the main regulator of melanogenesis. This leads to a reduction in skin hyperpigmentation induced by UV [6; 7; 8]. Like sesamol, sesamolin has antioxidative properties, neutralizes free radicals, and boosts the activity of antioxidative enzymes, which are crucial in neutralizing reactive oxygen species caused by UVB radiation [6; 8; 9]. Lecithin is a component of cell membranes that helps to maintain the integrity and stability of skin lipids. UV radiation can lead to lipid peroxidation, which destabilizes cell membranes. Lecithin is an antioxidant that helps protect skin cells [9]. The growing awareness of the risks of solar radiation on the skin is having an impact on the cosmetics industry, especially the tanning products segment. Recently, natural products have gained interest. Sunscreen manufacturers have added natural raw materials with a sun-protective effect, such as vegetable oils, to cosmetic formulas. Oils have a low sun protection factor, so they cannot be used alone. Most are often combined with substances with higher photoprotective properties, such as physical or chemical filters. Due to their antioxidative and anti-inflammatory properties, vegetable oils aid in minimizing the effects of UV exposure and have a beneficial impact on the skin's condition [10]. Photop protection is crucial in preventing the consequences of long-term exposure to solar radiation, which causes visible deterioration in the structure and function of the skin. More serious effects include an increased risk of carcinogenesis and the development of skin cancer. Topical application of photoprotective preparations that contain active molecules that absorb or reflect UV radiation on the skin is the most common method for reducing the penetration of UV radiation on the skin. The aim of this study was to evaluate the sun protection properties of sesame oil when applied to the skin. Currently, efforts are underway to find substances that can absorb or reflect UV radiation without affecting the skin. However, the literature lacks in vivo studies. Such research is necessary to objectively assess how effectively the oil provides protection against radiation when applied to the skin. The study was performed in vivo using a non-invasive hemispherical directional reflectance method. The use of hemispherical directional reflection to examine skin and cosmetic products has recently been demonstrated to be an effective method for assessing their quantitative and qualitative interactions with electromagnetic radiation in the spectral range from 335 to 2500 nm [11; 12; 13].