Introduction: Active ingredients inspired by nature are increasingly being developed and incorporated into cosmetics and beauty products. Molecules from nature, such as mycosporine-like amino acids (MAAs) from aquatic environments and sinapoyl malate (SM) from the plant kingdom have individually been shown to have beneficial cosmetic properties, such as anti-aging and UV absorption. However, it is currently unknown whether combining these two ingredients from different natural sources can work together to enhance their favourable qualities with a synergistic effect. If synergies can be identified, this could alleviate some of the challenges associated with low extracted yields of natural active ingredients. Furthermore, the concentrations of other active ingredients could be reduced if our ingredients can boost their activity.

Methods: Commercial forms and isolated dried extracts of products containing garden cress sprout extract (Lepidium sativum) and red Nori algae extract (Porphyra umbilicalis) were blended in different combinations to investigate whether they enhance the activity of one another. Each combination has been studied using state-of-the-art ultrafast laser spectroscopy (ULS) to track the energy flow within photoactive compounds in real time, from the instant that UV radiation is absorbed. Additional complementary investigations, which include in vitro SPF determination and solar irradiation studies, offer a highly detailed picture of how the different ingredients can work together, following exposure to UV radiation.

Results and discussion: ULS measurements of several commercial form combinations reveal that the MAAs contained within the Nori-based product show dominance over the SM in the cress-based product, a consequence, in part, due to the liposomal encapsulation of the cress extract. However, further ULS measurements on the dried extracts alone showed that the garden cress sprout extract (non-encapsulated) dominated over the Nori. It also reveals that liposomal encapsulation mimics a non-polar solvent environment. Excellent photostability (less than 10% degradation in all cases for the commercial forms) was also demonstrated in irradiation tests using a solar simulation lamp over two hours. These observations are supported by in vitro SPF measurements, which revealed that the SPF value of the two commercial forms added at 10% by volume to water (46.4) is significantly higher than the sum of the ingredients separately (6.7 and 18.0), which is strong evidence of a synergy between the two ingredients. The exact explanations for the synergies observed between the active ingredients are currently being investigated; however, preliminary results show the potential of fine-tuning the ratios of these nature-based ingredients for maximum cosmetic effect.

Conclusions: It is well-known that MAAs are a future star of the cosmetics world, and we believe that SM also has this potential. The highly concentrated cress sprout extract, resulting from the fact that the concentration of SM in a plant is highest following germination, could be added to products containing MAAs. This way, biomimicry from both the land and the sea can blend in harmony for the enhancement of cosmetic properties. This could incorporate both properties which they have already been proven to possess, such as anti-aging, pollution protection and antioxidation, whilst adding the potential of new activities, such as UV boosting, which we begin to demonstrate in this study.