Juine Arvie J. Lavarias. 4 0

UV/VISIBLE spectra of selected natural photoprotective flavanoids: a density functional theory study / 6 6 Juine Arvie J. Lavarias. - - - 46 pp. 28 cm. - - - - - . - . - 0 . - . - 0 .

Thesis: (Bachelor of Science in Chemistry) - Pamantasan ng Lungsod ng Maynila, 2022.





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ABSTRACT: Overexposure to sunlight will cause adverse effects to our skin. This is due to the ultraviolet radiation that is entering through our ozone layer. With that being said, many recommendations were suggested for the defense of our skin to sunlight, and sunscreen is the most recommended. However, the preferred chemical sunscreens can cause adverse effects on skin when in contact with ultraviolet radiation. Natural flavonoids specifically quercetin, luteolin, naringenin, genistein, catechin, and cyaniding, showed photoprotection as one of their biological activities. In this study, the said flavonoids were subjected to a density functional theory study using B3LYP as level of method and def2-TZVP as basis set. The researcher tested the robustness of the method and got a correlation coefficient of 0.92, giving a pretty strong positive correlation to the experimental value of their maximum absorption. This result demonstrates that B3LYP/def2-TZVP is an effective method, thus can be used to predict new derivatives of flavonoids and their absorption wavelength, that can be used as natural alternative for adjuvants of sunscreen. The calculations also made the researcher to found out that absence of 2,3 double bonds, OH group at C3, and charge of the compound will have an affect to the shift of their maximum absorption.













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