Stem-202 Group Project 2
Participants: Hailey Chin, Sophia DiMaggio, Claire Hawley
Course: STEM Scholars’ Research Lab II, STEM-202-HN01
Assignment Title: The Effectiveness of Organic UV Filters Derived from Plant Material incorporated into a Natural Sunscreen Product
Assignment Details
Sunscreen has taken many forms throughout history, from olive oil to mud. In modern times, sunscreens are made up of countless chemicals and have become the topic of debate regarding safety concerns. The purpose of our project was to synthesize three sunscreens derived from natural, plant-based UV filters, such as flavonoids, polyphenols, amino acids, and carotenoids. Our product’s effectiveness was tested on yeast, Saccharomyces cerevisiae, which shows reduced colony number and size when exposed to UV. Secondary experimentation was conducted to strengthen our research using a UV-sensitive lab-grade paper and a UV-Index meter. A marketed chemical sunscreen, Banana Boat, was used as a positive control for all experimentation. A plate of yeast with no sunscreen was used as a negative control.
Application
The effectiveness of our sunscreen was tested on baker’s yeast, a microorganism sensitive to UV radiation. To establish the baseline for their sensitivity, we irritated them for various time frames: 40, 50, and 60 minutes at a concentration of 10^(-4) CFU/mL (colony forming units). In doing this, we were able to count the number of colonies present on each plate after irradiation times and quantitatively determine the most effective time frame for our research.
Plants, despite using the sun for photosynthesis, can still suffer from UV damage similar to humans. Many plants have developed anti-UV chemicals to protect the sensitive tissue underneath their cuticles. Examples of these natural sunscreens used by plants are flavonoids, phenolic acids, and polyphenols. These chemicals work to absorb UV radiation before it can damage cells. By using extracts of these plants, their anti-UV properties can be harnessed for human use in sunscreens
Results/Conclusions
Our results showed that the best-performing sunscreen we synthesized was derived from rutin powder. It outperformed the Banana Boat sunscreen against the light meter and maintained a higher yield of yeast colonies, 545 colonies compared to 498 colonies, during the 60-minute plate irradiation tests. The other sunscreen formulas produced also showed promise for effectively being able to filter out dangerous UV wavelengths, with the average colony count of tamanu oil being 412 colonies and green tea being 310 colonies. Each sunscreen filtered out all UVC rays and showed a significant decrease in the UVA and UVB wavelengths able to penetrate through it.