Effects of Different Chemical Modifications on the Polysaccharide Structure, Antioxidant, and Whitening Activities of <i>Lavandula angustifolia</i> Mill

-induced oxidative stress by regulating malondialdehyde (MDA) content and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Whitening activity experiments demonstrated that all derivatives were more effective than the native polysaccharide in reducing melanin content and tyrosinase activity. Among them, LAP-S exhibited the strongest inhibitory effect, reducing melanin content and tyrosinase activity by 56.49% ± 0.37% and 67.45% ± 0.32%, respectively, compared to the model group. In contrast, LAP-Se showed the weakest inhibitory effect, with melanin content and tyrosinase activity decreasing by only 37.77% ± 0.29% and 50.87% ± 0.35%, respectively, compared to the model group. This study indicates that LAP and its derivatives hold significant potential for application in the development of novel skincare products.