Study of the antimicrobial and antioxidant activity of lipsticks and soaps made with phycoerythrin coated with chitosan extracted from the cyanobacterium Aliinostoc oryzae

The use of various artificial dyes in the preparation of cosmetics for over half a century has led to an increase in cancer diseases in humans. On the other hand, the excessive use of synthetic antibiotics available on the market, which have been used for treating humans and animals for over half a century, has significantly reduced the efficacy of many antibiotics due to the development of bacterial resistance. In contrast, phycoerythrin (PE) as a natural pigment possesses potential antioxidant and antimicrobial properties. Therefore, this article aims to use PE to create soap and cosmetic lipsticks that not only ensure consumer health but also avoid the harmful effects of chemical compounds present in cosmetic products. In the present study, PE extracted from the cyanobacterium Aliinostoc oryzae was microencapsulated with chitosan and added to the formulation of solid soap and lipstick. All standard tests were performed at intervals of 1, 5, 10, 15, 20, 25, and 30 days and compared with controls. The percentage change in the hardness of lipsticks enriched with PE was significantly higher than the control (p ≤ 0.05), while the amount of force required during use was significantly lower than the control (p ≤ 0.05). In soaps enriched with PE, the moisture reduction trend over time was steeper in soaps without PE. Additionally, the antioxidant activity and insoluble substances in alcohol in PE-enriched soaps were significantly higher than the control sample, while the percentage of lipid compounds and the unsaponifiable matter of free alkali in the control sample were significantly higher than the Soap + PE sample (p ≤ 0.05). Over time, the L* color component of all enriched products decreased significantly, while the a*, b*, and ΔE color components increased significantly (p ≤ 0.05). Moreover, the total microbial population, inhibition zone diameter, and peroxide index in enriched products were significantly lower than the control. Overall, the enriched products did not cause any skin sensitivity, and color changes and stability remained consistent over time. All these results confirm the claim that chitosan-coated PE, as an effective additive, has significant efficacy in cosmetic products. • Soaps containing phycoerythrin showed higher antioxidant activity. • Products enriched with phycoerythrin showed fewer bacteria and showed stronger antimicrobial effects. • Lipsticks enriched with phycoerythrin demonstrated greater hardness and required less force during application. • Phycoerythrin-enriched products exhibited lower microbial populations compared to controls. • The addition of phycoerythrin improved color stability and prevented skin sensitivity in all products.